Buildbot documentation for Buildbot version 1.6.0

Оригинал статьи:

1. Buildbot Tutorial


1.1. First Run

1.1.1. Goal

This tutorial will take you from zero to running your first buildbot master and worker as quickly as possible, without changing the default configuration.

This tutorial is all about instant gratification and the five minute experience: in five minutes we want to convince you that this project works, and that you should seriously consider spending time learning the system. In this tutorial no configuration or code changes are done.

This tutorial assumes that you are running Unix, but might be adaptable to Windows.

Thanks to virtualenv, installing buildbot in a standalone environment is very easy. For those more familiar with Docker, there also exists a docker version of these instructions.

You should be able to cut and paste each shell block from this tutorial directly into a terminal.

1.1.2. Getting ready

There are many ways to get the code on your machine. We will use the easiest one: via pip in a virtualenv. It has the advantage of not polluting your operating system, as everything will be contained in the virtualenv.

To make this work, you will need the following installed:

Preferably, use your distribution package manager to install these.

You will also need a working Internet connection, as virtualenv and pip will need to download other projects from the Internet.


Buildbot does not require root access. Run the commands in this tutorial as a normal, unprivileged user.

1.1.3. Creating a master

The first necessary step is to create a virtualenv for our master. We will also use a separate directory to demonstrate the distinction between a master and worker:

mkdir -p ~/tmp/bb-master
cd ~/tmp/bb-master

On Python 2:

virtualenv --no-site-packages sandbox
source sandbox/bin/activate

On Python 3:

python3 -m venv sandbox
source sandbox/bin/activate

Now that we are ready, we need to install buildbot:

pip install --upgrade pip
pip install 'buildbot[bundle]'

Now that buildbot is installed, it’s time to create the master:

buildbot create-master master

Buildbot’s activity is controlled by a configuration file. We will use the sample configuration file unchanged:

mv master/master.cfg.sample master/master.cfg

Finally, start the master:

buildbot start master

You will now see some log information from the master in this terminal. It should end with lines like these:

2014-11-01 15:52:55+0100 [-] BuildMaster is running
The buildmaster appears to have (re)started correctly.

From now on, feel free to visit the web status page running on the port 8010: http://localhost:8010/

Our master now needs (at least) a worker to execute its commands. For that, head on to the next section!

1.1.4. Creating a worker

The worker will be executing the commands sent by the master. In this tutorial, we are using the buildbot/hello-world project as an example. As a consequence of this, your worker will need access to the git command in order to checkout some code. Be sure that it is installed, or the builds will fail.

Same as we did for our master, we will create a virtualenv for our worker next to the other one. It would however be completely ok to do this on another computer - as long as the worker computer is able to connect to the master one:

mkdir -p ~/tmp/bb-worker
cd ~/tmp/bb-worker

On Python 2:

virtualenv --no-site-packages sandbox
source sandbox/bin/activate

On Python 3:

python3 -m venv sandbox
source sandbox/bin/activate

Install the buildbot-worker command:

pip install --upgrade pip
pip install buildbot-worker
# required for `runtests` build
pip install setuptools-trial

Now, create the worker:

buildbot-worker create-worker worker localhost example-worker pass


If you decided to create this from another computer, you should replace localhost with the name of the computer where your master is running.

The username (example-worker), and password (pass) should be the same as those in master/master.cfg; verify this is the case by looking at the section for c['workers']:

cat ../bb-master/master/master.cfg

And finally, start the worker:

buildbot-worker start worker

Check the worker’s output. It should end with lines like these:

2014-11-01 15:56:51+0100 [-] Connecting to localhost:9989
2014-11-01 15:56:51+0100 [Broker,client] message from master: attached
The worker appears to have (re)started correctly.

Meanwhile, from the other terminal, in the master log (twisted.log in the master directory), you should see lines like these:

2014-11-01 15:56:51+0100 [Broker,1,] worker 'example-worker' attaching from IPv4Address(TCP, '', 54015)
2014-11-01 15:56:51+0100 [Broker,1,] Got workerinfo from 'example-worker'
2014-11-01 15:56:51+0100 [-] bot attached

You should now be able to go to http://localhost:8010, where you will see a web page similar to:

index page

Click on the Waterfall Display link and you get this:

empty waterfall.

Your master is now quietly waiting for new commits to hello-world. This doesn’t happen very often though. In the next section, we’ll see how to manually start a build.

We just wanted to get you to dip your toes in the water. It’s easy to take your first steps, but this is about as far as we can go without touching the configuration.

You’ve got a taste now, but you’re probably curious for more. Let’s step it up a little in the second tutorial by changing the configuration and doing an actual build. Continue on to A Quick Tour.

1.2. First Buildbot run with Docker


Docker can be tricky to get working correctly if you haven’t used it before. If you’re having trouble, first determine whether it is a Buildbot issue or a Docker issue by running:

docker run ubuntu:12.04 apt-get update

If that fails, look for help with your Docker install. On the other hand, if that succeeds, then you may have better luck getting help from members of the Buildbot community.

Docker is a tool that makes building and deploying custom environments a breeze. It uses lightweight linux containers (LXC) and performs quickly, making it a great instrument for the testing community. The next section includes a Docker pre-flight check. If it takes more that 3 minutes to get the ‘Success’ message for you, try the Buildbot pip-based first run instead.

1.2.1. Current Docker dependencies

  • Linux system, with at least kernel 3.8 and AUFS support. For example, Standard Ubuntu, Debian and Arch systems.
  • Packages: lxc, iptables, ca-certificates, and bzip2 packages.
  • Local clock on time or slightly in the future for proper SSL communication.
  • This tutorial uses docker-compose to run a master, a worker, and a postgresql database server

1.2.2. Installation

  • Use the Docker installation instructions for your operating system.

  • Make sure you install docker-compose. As root or inside a virtualenv, run:

    pip install docker-compose
  • Test docker is happy in your environment:

    sudo docker run -i busybox /bin/echo Success

1.2.3. Building and running Buildbot

# clone the example repository
git clone --depth 1

# Build the Buildbot container (it will take a few minutes to download packages)
cd buildbot-docker-example-config/simple
docker-compose up

You should now be able to go to http://localhost:8010 and see a web page similar to:

index page

Click on the Waterfall Display link and you get this:

empty waterfall.

1.2.4. Overview of the docker-compose configuration

This docker-compose configuration is made as a basis for what you would put in production

  • Separated containers for each component
  • A solid database backend with postgresql
  • A buildbot master that exposes its configuration to the docker host
  • A buildbot worker that can be cloned in order to add additional power
  • Containers are linked together so that the only port exposed to external is the web server
  • The default master container is based on Alpine linux for minimal footprint
  • The default worker container is based on more widely known Ubuntu distribution, as this is the container you want to customize.
  • Download the config from a tarball accessible via a web server

1.2.5. Playing with your Buildbot containers

If you’ve come this far, you have a Buildbot environment that you can freely experiment with.

In order to modify the configuration, you need to fork the project on github Then you can clone your own fork, and start the docker-compose again.

To modify your config, edit the master.cfg file, commit your changes, and push to your fork. You can use the command buildbot check-config in order to make sure the config is valid before the push. You will need to change docker-compose.yml the variable BUILDBOT_CONFIG_URL in order to point to your github fork.

The BUILDBOT_CONFIG_URL may point to a .tar.gz file accessible from HTTP. Several git servers like github can generate that tarball automatically from the master branch of a git repository If the BUILDBOT_CONFIG_URL does not end with .tar.gz, it is considered to be the URL to a master.cfg file accessible from HTTP.

1.2.6. Customize your Worker container

It is advised to customize you worker container in order to suit your project’s build dependencies and need. An example DockerFile is available which the buildbot community uses for its own CI purposes:

1.2.7. Multi-master

A multi-master environment can be setup using the multimaster/docker-compose.yml file in the example repository

# Build the Buildbot container (it will take a few minutes to download packages) cd buildbot-docker-example-config/simple docker-compose up -d docker-compose scale buildbot=4

1.2.8. Going forward

You’ve got a taste now, but you’re probably curious for more. Let’s step it up a little in the second tutorial by changing the configuration and doing an actual build. Continue on to A Quick Tour.

1.3. A Quick Tour

1.3.1. Goal

This tutorial will expand on the First Run tutorial by taking a quick tour around some of the features of buildbot that are hinted at in the comments in the sample configuration. We will simply change parts of the default configuration and explain the activated features.

As a part of this tutorial, we will make buildbot do a few actual builds.

This section will teach you how to:

  • make simple configuration changes and activate them
  • deal with configuration errors
  • force builds
  • enable and control the IRC bot
  • enable ssh debugging
  • add a ‘try’ scheduler

1.3.2. Setting Project Name and URL

Let’s start simple by looking at where you would customize the buildbot’s project name and URL.

We continue where we left off in the First Run tutorial.

Open a new terminal, and first enter the same sandbox you created before (where $EDITOR is your editor of choice like vim, gedit, or emacs):

cd ~/tmp/bb-master
source sandbox/bin/activate
$EDITOR master/master.cfg

Now, look for the section marked PROJECT IDENTITY which reads:


# the 'title' string will appear at the top of this buildbot installation's
# home pages (linked to the 'titleURL').

c['title'] = "Hello World CI"
c['titleURL'] = ""

If you want, you can change either of these links to anything you want to see what happens when you change them.

After making a change go into the terminal and type:

buildbot reconfig master

You will see a handful of lines of output from the master log, much like this:

2011-12-04 10:11:09-0600 [-] loading configuration from /home/dustin/tmp/buildbot/master/master.cfg
2011-12-04 10:11:09-0600 [-] configuration update started
2011-12-04 10:11:09-0600 [-] builder runtests is unchanged
2011-12-04 10:11:09-0600 [-] removing IStatusReceiver <WebStatus on port tcp:8010 at 0x2aee368>
2011-12-04 10:11:09-0600 [-] (TCP Port 8010 Closed)
2011-12-04 10:11:09-0600 [-] Stopping factory <buildbot.status.web.baseweb.RotateLogSite instance at 0x2e36638>
2011-12-04 10:11:09-0600 [-] adding IStatusReceiver <WebStatus on port tcp:8010 at 0x2c2d950>
2011-12-04 10:11:09-0600 [-] RotateLogSite starting on 8010
2011-12-04 10:11:09-0600 [-] Starting factory <buildbot.status.web.baseweb.RotateLogSite instance at 0x2e36e18>
2011-12-04 10:11:09-0600 [-] Setting up http.log rotating 10 files of 10000000 bytes each
2011-12-04 10:11:09-0600 [-] WebStatus using (/home/dustin/tmp/buildbot/master/public_html)
2011-12-04 10:11:09-0600 [-] removing 0 old schedulers, updating 0, and adding 0
2011-12-04 10:11:09-0600 [-] adding 1 new changesources, removing 1
2011-12-04 10:11:09-0600 [-] gitpoller: using workdir '/home/dustin/tmp/buildbot/master/gitpoller-workdir'
2011-12-04 10:11:09-0600 [-] GitPoller repository already exists
2011-12-04 10:11:09-0600 [-] configuration update complete

Reconfiguration appears to have completed successfully.

The important lines are the ones telling you that it is loading the new configuration at the top, and the one at the bottom saying that the update is complete.

Now, if you go back to the waterfall page, you will see that the project’s name is whatever you may have changed it to and when you click on the URL of the project name at the bottom of the page it should take you to the link you put in the configuration.

1.3.3. Configuration Errors

It is very common to make a mistake when configuring buildbot, so you might as well see now what happens in that case and what you can do to fix the error.

Open up the config again and introduce a syntax error by removing the first single quote in the two lines you changed, so they read:

c[title'] = "Hello World CI"
c[titleURL'] = ""

This creates a Python SyntaxError. Now go ahead and reconfig the buildmaster:

buildbot reconfig master

This time, the output looks like:

2015-08-14 18:40:46+0000 [-] beginning configuration update
2015-08-14 18:40:46+0000 [-] Loading configuration from '/data/buildbot/master/master.cfg'
2015-08-14 18:40:46+0000 [-] error while parsing config file:
        Traceback (most recent call last):
          File "/usr/local/lib/python2.7/dist-packages/buildbot/", line 265, in reconfig
            d = self.doReconfig()
          File "/usr/local/lib/python2.7/dist-packages/twisted/internet/", line 1274, in unwindGenerator
            return _inlineCallbacks(None, gen, Deferred())
          File "/usr/local/lib/python2.7/dist-packages/twisted/internet/", line 1128, in _inlineCallbacks
            result = g.send(result)
          File "/usr/local/lib/python2.7/dist-packages/buildbot/", line 289, in doReconfig
        --- <exception caught here> ---
          File "/usr/local/lib/python2.7/dist-packages/buildbot/", line 156, in loadConfig
            exec f in localDict
        exceptions.SyntaxError: EOL while scanning string literal (master.cfg, line 103)

2015-08-14 18:40:46+0000 [-] error while parsing config file: EOL while scanning string literal (master.cfg, line 103) (traceback in logfile)
2015-08-14 18:40:46+0000 [-] reconfig aborted without making any changes

Reconfiguration failed. Please inspect the master.cfg file for errors,
correct them, then try 'buildbot reconfig' again.

This time, it’s clear that there was a mistake in the configuration. Luckily, the Buildbot master will ignore the wrong configuration and keep running with the previous configuration.

The message is clear enough, so open the configuration again, fix the error, and reconfig the master.

1.3.4. Your First Build

By now you’re probably thinking: “All this time spent and still not done a single build? What was the name of this project again?”

On the Builders page, click on the runtests link. You’ll see a builder page, and an option that allow you to force a build:

force a build.

Click Start Build - there’s no need to fill in any of the fields in this case. Next, click on view in waterfall.

You will now see:

an successful test run happened.

1.3.5. Enabling the IRC Bot

Buildbot includes an IRC bot that you can tell to join a channel and control to report on the status of buildbot.


Security Note

Please note that any user having access to your irc channel or can PM the bot will be able to create or stop builds bug #3377.

First, start an IRC client of your choice, connect to and join an empty channel. In this example we will use #buildbot-test, so go join that channel. (Note: please do not join the main buildbot channel!)

Edit master.cfg and look for the BUILDBOT SERVICES section. At the end of that section add the lines:

c['services'].append(reporters.IRC(host="", nick="bbtest",

Reconfigure the build master then do:

grep -i irc master/twistd.log

The log output should contain a line like this:

2016-11-13 15:53:06+0100 [-] Starting factory <buildbot.reporters.irc.IrcStatusFactory instance at 0x7ff2b4b72710>
2016-11-13 15:53:19+0100 [IrcStatusBot,client] <buildbot.reporters.irc.IrcStatusBot object at 0x7ff2b5075750>: I have joined #buildbot-test

You should see the bot now joining in your IRC client. In your IRC channel, type:

bbtest: commands

to get a list of the commands the bot supports.

Let’s tell the bot to notify certain events, to learn which EVENTS we can notify on:

bbtest: help notify

Now let’s set some event notifications:

<@lsblakk> bbtest: notify on started finished failure
< bbtest> The following events are being notified: ['started', 'failure', 'finished']

Now, go back to the web interface and force another build. Alternatively, ask the bot to force a build:

<@lsblakk> bbtest: force build --codebase= runtests
< bbtest> build #1 of runtests started
< bbtest> Hey! build runtests #1 is complete: Success [finished]

You can also see the new builds in the web interface.

a successful test run from IRC happened.

The full documentation is available at IRC.

1.3.6. Setting Authorized Web Users

The default configuration allows everyone to perform any task like creating or stopping builds via the web interface. To restrict this to a user, look for:

c['www'] = dict(port=8010,
                 plugins=dict(waterfall_view={}, console_view={}))

and append:

c['www']['authz'] = util.Authz(
        allowRules = [
        roleMatchers = [
            util.RolesFromUsername(roles=['admins'], usernames=['Alice'])
c['www']['auth'] = util.UserPasswordAuth([('Alice','Password1')])

For more details, see Authentication plugins.

1.3.7. Debugging with Manhole

You can do some debugging by using manhole, an interactive Python shell. It exposes full access to the buildmaster’s account (including the ability to modify and delete files), so it should not be enabled with a weak or easily guessable password.

To use this you will need to install an additional package or two to your virtualenv:

cd ~/tmp/bb-master
source sandbox/bin/activate
pip install -U pip
pip install cryptography pyasn1

You will also need to generate an SSH host key for the Manhole server.

mkdir -p /data/ssh_host_keys
ckeygen -t rsa -f /data/ssh_host_keys/ssh_host_rsa_key

In your master.cfg find:

c = BuildmasterConfig = {}

Insert the following to enable debugging mode with manhole:

from buildbot import manhole
c['manhole'] = manhole.PasswordManhole("tcp:1234:interface=","admin","passwd", ssh_hostkey_dir="/data/ssh_host_keys/")

After restarting the master, you can ssh into the master and get an interactive Python shell:

ssh -p1234 admin@
# enter passwd at prompt


The pyasn1-0.1.1 release has a bug which results in an exception similar to this on startup:

exceptions.TypeError: argument 2 must be long, not int

If you see this, the temporary solution is to install the previous version of pyasn1:

pip install pyasn1-0.0.13b

If you wanted to check which workers are connected and what builders those workers are assigned to you could do:

>>> master.workers.workers
{'example-worker': <Worker 'example-worker', current builders: runtests>}

Objects can be explored in more depth using dir(x) or the helper function show(x).

1.3.8. Adding a ‘try’ scheduler

Buildbot includes a way for developers to submit patches for testing without committing them to the source code control system. (This is really handy for projects that support several operating systems or architectures.)

To set this up, add the following lines to master.cfg:

from buildbot.scheduler import Try_Userpass
c['schedulers'] = []

Then you can submit changes using the try command.

Let’s try this out by making a one-line change to hello-world, say, to make it trace the tree by default:

git clone git:// hello-world-git
cd hello-world-git/hello
# change 'return "hello " + who' on line 6 to 'return "greets " + who'

Then run buildbot’s try command as follows:

cd ~/tmp/bb-master
source sandbox/bin/activate
buildbot try --connect=pb --master= --username=sampleuser --passwd=samplepass --vc=git

This will do git diff for you and send the resulting patch to the server for build and test against the latest sources from Git.

Now go back to the waterfall page, click on the runtests link, and scroll down. You should see that another build has been started with your change (and stdout for the tests should be chock-full of parse trees as a result). The “Reason” for the job will be listed as “‘try’ job”, and the blamelist will be empty.

To make yourself show up as the author of the change, use the --who=emailaddr option on buildbot tryto pass your email address.

To make a description of the change show up, use the --properties=comment="this is a comment"option on buildbot try.

To use ssh instead of a private username/password database, see Try_Jobdir.

1.4. Further Reading

See the following user-contributed tutorials for other highlights and ideas:

1.4.1. Buildbot in 5 minutes - a user-contributed tutorial

(Ok, maybe 10.)

Buildbot is really an excellent piece of software, however it can be a bit confusing for a newcomer (like me when I first started looking at it). Typically, at first sight it looks like a bunch of complicated concepts that make no sense and whose relationships with each other are unclear. After some time and some reread, it all slowly starts to be more and more meaningful, until you finally say “oh!” and things start to make sense. Once you get there, you realize that the documentation is great, but only if you already know what it’s about.

This is what happened to me, at least. Here I’m going to (try to) explain things in a way that would have helped me more as a newcomer. The approach I’m taking is more or less the reverse of that used by the documentation, that is, I’m going to start from the components that do the actual work (the builders) and go up the chain from there up to change sources. I hope purists will forgive this unorthodoxy. Here I’m trying to clarify the concepts only, and will not go into the details of each object or property; the documentation explains those quite well. Installation

I won’t cover the installation; both Buildbot master and worker are available as packages for the major distributions, and in any case the instructions in the official documentation are fine. This document will refer to Buildbot 0.8.5 which was current at the time of writing, but hopefully the concepts are not too different in other versions. All the code shown is of course python code, and has to be included in the master.cfg master configuration file.

We won’t cover the basic things such as how to define the workers, project names, or other administrative information that is contained in that file; for that, again the official documentation is fine. Builders: the workhorses

Since Buildbot is a tool whose goal is the automation of software builds, it makes sense to me to start from where we tell Buildbot how to build our software: the builder (or builders, since there can be more than one).

Simply put, a builder is an element that is in charge of performing some action or sequence of actions, normally something related to building software (for example, checking out the source, or make all), but it can also run arbitrary commands.

A builder is configured with a list of workers that it can use to carry out its task. The other fundamental piece of information that a builder needs is, of course, the list of things it has to do (which will normally run on the chosen worker). In Buildbot, this list of things is represented as a BuildFactory object, which is essentially a sequence of steps, each one defining a certain operation or command.

Enough talk, let’s see an example. For this example, we are going to assume that our super software project can be built using a simple make all, and there is another target make packages that creates rpm, deb and tgz packages of the binaries. In the real world things are usually more complex (for example there may be a configure step, or multiple targets), but the concepts are the same; it will just be a matter of adding more steps to a builder, or creating multiple builders, although sometimes the resulting builders can be quite complex.

So to perform a manual build of our project we would type this from the command line (assuming we are at the root of the local copy of the repository):

$ make clean    # clean remnants of previous builds
$ svn update
$ make all
$ make packages
# optional but included in the example: copy packages to some central machine
$ scp packages/*.rpm packages/*.deb packages/*.tgz someuser@somehost:/repository

Here we’re assuming the repository is SVN, but again the concepts are the same with git, mercurial or any other VCS.

Now, to automate this, we create a builder where each step is one of the commands we typed above. A step can be a shell command object, or a dedicated object that checks out the source code (there are various types for different repositories, see the docs for more info), or yet something else:

from buildbot.plugins import steps, util

# first, let's create the individual step objects

# step 1: make clean; this fails if the worker has no local copy, but
# is harmless and will only happen the first time
makeclean = steps.ShellCommand(name="make clean",
                               command=["make", "clean"],
                               description="make clean")

# step 2: svn update (here updates trunk, see the docs for more
# on how to update a branch, or make it more generic).
checkout = steps.SVN(baseURL='svn://myrepo/projects/coolproject/trunk',

# step 3: make all
makeall = steps.ShellCommand(name="make all",
                             command=["make", "all"],
                             description="make all")

# step 4: make packages
makepackages = steps.ShellCommand(name="make packages",
                                  command=["make", "packages"],
                                  description="make packages")

# step 5: upload packages to central server. This needs passwordless ssh
# from the worker to the server (set it up in advance as part of worker setup)
uploadpackages = steps.ShellCommand(name="upload packages",
                                    description="upload packages",
                                    command="scp packages/*.rpm packages/*.deb packages/*.tgz someuser@somehost:/repository",

# create the build factory and add the steps to it
f_simplebuild = util.BuildFactory()

# finally, declare the list of builders. In this case, we only have one builder
c['builders'] = [
    util.BuilderConfig(name="simplebuild", workernames=['worker1', 'worker2', 'worker3'], factory=f_simplebuild)

So our builder is called simplebuild and can run on either of worker1worker2 and worker3. If our repository has other branches besides trunk, we could create another one or more builders to build them; in the example, only the checkout step would be different, in that it would need to check out the specific branch. Depending on how exactly those branches have to be built, the shell commands may be recycled, or new ones would have to be created if they are different in the branch. You get the idea. The important thing is that all the builders be named differently and all be added to the c['builders'] value (as can be seen above, it is a list of BuilderConfig objects).

Of course the type and number of steps will vary depending on the goal; for example, to just check that a commit doesn’t break the build, we could include just up to the make all step. Or we could have a builder that performs a more thorough test by also doing make test or other targets. You get the idea. Note that at each step except the very first we use haltOnFailure=True because it would not make sense to execute a step if the previous one failed (ok, it wouldn’t be needed for the last step, but it’s harmless and protects us if one day we add another step after it). Schedulers

Now this is all nice and dandy, but who tells the builder (or builders) to run, and when? This is the job of the scheduler, which is a fancy name for an element that waits for some event to happen, and when it does, based on that information decides whether and when to run a builder (and which one or ones). There can be more than one scheduler. I’m being purposely vague here because the possibilities are almost endless and highly dependent on the actual setup, build purposes, source repository layout and other elements.

So a scheduler needs to be configured with two main pieces of information: on one hand, which events to react to, and on the other hand, which builder or builders to trigger when those events are detected. (It’s more complex than that, but if you understand this, you can get the rest of the details from the docs).

A simple type of scheduler may be a periodic scheduler: when a configurable amount of time has passed, run a certain builder (or builders). In our example, that’s how we would trigger a build every hour:

from buildbot.plugins import schedulers

# define the periodic scheduler
hourlyscheduler = schedulers.Periodic(name="hourly",

# define the available schedulers
c['schedulers'] = [hourlyscheduler]

That’s it. Every hour this hourly scheduler will run the simplebuild builder. If we have more than one builder that we want to run every hour, we can just add them to the builderNames list when defining the scheduler and they will all be run. Or since multiple scheduler are allowed, other schedulers can be defined and added to c['schedulers'] in the same way.

Other types of schedulers exist; in particular, there are schedulers that can be more dynamic than the periodic one. The typical dynamic scheduler is one that learns about changes in a source repository (generally because some developer checks in some change), and triggers one or more builders in response to those changes. Let’s assume for now that the scheduler “magically” learns about changes in the repository (more about this later); here’s how we would define it:

from buildbot.plugins import schedulers

# define the dynamic scheduler
trunkchanged = schedulers.SingleBranchScheduler(name="trunkchanged",

# define the available schedulers
c['schedulers'] = [trunkchanged]

This scheduler receives changes happening to the repository, and among all of them, pays attention to those happening in “trunk” (that’s what branch=None means). In other words, it filters the changes to react only to those it’s interested in. When such changes are detected, and the tree has been quiet for 5 minutes (300 seconds), it runs the simplebuild builder. The treeStableTimer helps in those situations where commits tend to happen in bursts, which would otherwise result in multiple build requests queuing up.

What if we want to act on two branches (say, trunk and 7.2)? First we create two builders, one for each branch (see the builders paragraph above), then we create two dynamic schedulers:

from buildbot.plugins import schedulers

# define the dynamic scheduler for trunk
trunkchanged = schedulers.SingleBranchScheduler(name="trunkchanged",

# define the dynamic scheduler for the 7.2 branch
branch72changed = schedulers.SingleBranchScheduler(name="branch72changed",

# define the available schedulers
c['schedulers'] = [trunkchanged, branch72changed]

The syntax of the change filter is VCS-dependent (above is for SVN), but again once the idea is clear, the documentation has all the details. Another feature of the scheduler is that it can be told which changes, within those it’s paying attention to, are important and which are not. For example, there may be a documentation directory in the branch the scheduler is watching, but changes under that directory should not trigger a build of the binary. This finer filtering is implemented by means of the fileIsImportant argument to the scheduler (full details in the docs and - alas - in the sources). Change sources

Earlier we said that a dynamic scheduler “magically” learns about changes; the final piece of the puzzle are change sources, which are precisely the elements in Buildbot whose task is to detect changes in the repository and communicate them to the schedulers. Note that periodic schedulers don’t need a change source, since they only depend on elapsed time; dynamic schedulers, on the other hand, do need a change source.

A change source is generally configured with information about a source repository (which is where changes happen); a change source can watch changes at different levels in the hierarchy of the repository, so for example it is possible to watch the whole repository or a subset of it, or just a single branch. This determines the extent of the information that is passed down to the schedulers.

There are many ways a change source can learn about changes; it can periodically poll the repository for changes, or the VCS can be configured (for example through hook scripts triggered by commits) to push changes into the change source. While these two methods are probably the most common, they are not the only possibilities; it is possible for example to have a change source detect changes by parsing some email sent to a mailing list when a commit happens, and yet other methods exist. The manual again has the details.

To complete our example, here’s a change source that polls a SVN repository every 2 minutes:

from buildbot.plugins import changes, util

svnpoller = changes.SVNPoller(repourl="svn://myrepo/projects/coolproject",

c['change_source'] = svnpoller

This poller watches the whole “coolproject” section of the repository, so it will detect changes in all the branches. We could have said:

repourl = "svn://myrepo/projects/coolproject/trunk"


repourl = "svn://myrepo/projects/coolproject/branches/7.2"

to watch only a specific branch.

To watch another project, you need to create another change source – and you need to filter changes by project. For instance, when you add a change source watching project ‘superproject’ to the above example, you need to change:

trunkchanged = schedulers.SingleBranchScheduler(name="trunkchanged",
                                                # ...

to e.g.:

trunkchanged = schedulers.SingleBranchScheduler(name="trunkchanged",
                                                change_filter=filter.ChangeFilter(project="coolproject", branch=None),
                                                # ...

else coolproject will be built when there’s a change in superproject.

Since we’re watching more than one branch, we need a method to tell in which branch the change occurred when we detect one. This is what the split_file argument does, it takes a callable that Buildbot will call to do the job. The split_file_branches function, which comes with Buildbot, is designed for exactly this purpose so that’s what the example above uses.

And of course this is all SVN-specific, but there are pollers for all the popular VCSs.

But note: if you have many projects, branches, and builders it probably pays to not hardcode all the schedulers and builders in the configuration, but generate them dynamically starting from list of all projects, branches, targets etc. and using loops to generate all possible combinations (or only the needed ones, depending on the specific setup), as explained in the documentation chapter about Customization. Reporters

Now that the basics are in place, let’s go back to the builders, which is where the real work happens.Reporters are simply the means Buildbot uses to inform the world about what’s happening, that is, how builders are doing. There are many reporters: a mail notifier, an IRC notifier, and others. They are described fairly well in the manual.

One thing I’ve found useful is the ability to pass a domain name as the lookup argument to a mailNotifier, which allows you to take an unqualified username as it appears in the SVN change and create a valid email address by appending the given domain name to it:

from buildbot.plugins import reporter

# if jsmith commits a change, mail for the build is sent to
notifier = reporter.MailNotifier(fromaddr="",

The mail notifier can be customized at will by means of the messageFormatter argument, which is a class that Buildbot calls to format the body of the email, and to which it makes available lots of information about the build. Here all the details. Conclusion

Please note that this article has just scratched the surface; given the complexity of the task of build automation, the possibilities are almost endless. So there’s much, much more to say about Buildbot. However, hopefully this is a preparation step before reading the official manual. Had I found an explanation as the one above when I was approaching Buildbot, I’d have had to read the manual just once, rather than multiple times. Hope this can help someone else.

(Thanks to Davide Brini for permission to include this tutorial, derived from one he originally posted at .)

This is the Buildbot manual for Buildbot version 1.6.0.

2. Buildbot Manual

2.1. Introduction

Buildbot is a system to automate the compile/test cycle required by most software projects to validate code changes. By automatically rebuilding and testing the tree each time something has changed, build problems are pinpointed quickly, before other developers are inconvenienced by the failure. The guilty developer can be identified and harassed without human intervention. By running the builds on a variety of platforms, developers who do not have the facilities to test their changes everywhere before checkin will at least know shortly afterwards whether they have broken the build or not. Warning counts, lint checks, image size, compile time, and other build parameters can be tracked over time, are more visible, and are therefore easier to improve.

The overall goal is to reduce tree breakage and provide a platform to run tests or code-quality checks that are too annoying or pedantic for any human to waste their time with. Developers get immediate (and potentially public) feedback about their changes, encouraging them to be more careful about testing before checkin.


  • run builds on a variety of worker platforms
  • arbitrary build process: handles projects using C, Python, whatever
  • minimal host requirements: Python and Twisted
  • workers can be behind a firewall if they can still do checkout
  • status delivery through web page, email, IRC, other protocols
  • track builds in progress, provide estimated completion time
  • flexible configuration by subclassing generic build process classes
  • debug tools to force a new build, submit fake Changes, query worker status
  • released under the GPL

2.1.1. History and Philosophy

The Buildbot was inspired by a similar project built for a development team writing a cross-platform embedded system. The various components of the project were supposed to compile and run on several flavors of unix (linux, solaris, BSD), but individual developers had their own preferences and tended to stick to a single platform. From time to time, incompatibilities would sneak in (some unix platforms want to use string.h, some prefer strings.h), and then the tree would compile for some developers but not others. The buildbot was written to automate the human process of walking into the office, updating a tree, compiling (and discovering the breakage), finding the developer at fault, and complaining to them about the problem they had introduced. With multiple platforms it was difficult for developers to do the right thing (compile their potential change on all platforms); the buildbot offered a way to help.

Another problem was when programmers would change the behavior of a library without warning its users, or change internal aspects that other code was (unfortunately) depending upon. Adding unit tests to the codebase helps here: if an application’s unit tests pass despite changes in the libraries it uses, you can have more confidence that the library changes haven’t broken anything. Many developers complained that the unit tests were inconvenient or took too long to run: having the buildbot run them reduces the developer’s workload to a minimum.

In general, having more visibility into the project is always good, and automation makes it easier for developers to do the right thing. When everyone can see the status of the project, developers are encouraged to keep the tree in good working order. Unit tests that aren’t run on a regular basis tend to suffer from bitrot just like code does: exercising them on a regular basis helps to keep them functioning and useful.

The current version of the Buildbot is additionally targeted at distributed free-software projects, where resources and platforms are only available when provided by interested volunteers. The workers are designed to require an absolute minimum of configuration, reducing the effort a potential volunteer needs to expend to be able to contribute a new test environment to the project. The goal is for anyone who wishes that a given project would run on their favorite platform should be able to offer that project a worker, running on that platform, where they can verify that their portability code works, and keeps working.

2.1.2. System Architecture

The Buildbot consists of a single buildmaster and one or more workers, connected in a star topology. The buildmaster makes all decisions about what, when, and how to build. It sends commands to be run on the workers, which simply execute the commands and return the results. (certain steps involve more local decision making, where the overhead of sending a lot of commands back and forth would be inappropriate, but in general the buildmaster is responsible for everything).

The buildmaster is usually fed Changes by some sort of version control system (Change Sources and Changes), which may cause builds to be run. As the builds are performed, various status messages are produced, which are then sent to any registered Reporters.

Overview Diagram

The buildmaster is configured and maintained by the buildmaster admin, who is generally the project team member responsible for build process issues. Each worker is maintained by a worker admin, who do not need to be quite as involved. Generally workers are run by anyone who has an interest in seeing the project work well on their favorite platform. Worker Connections

The workers are typically run on a variety of separate machines, at least one per platform of interest. These machines connect to the buildmaster over a TCP connection to a publicly-visible port. As a result, the workers can live behind a NAT box or similar firewalls, as long as they can get to buildmaster. The TCP connections are initiated by the worker and accepted by the buildmaster, but commands and results travel both ways within this connection. The buildmaster is always in charge, so all commands travel exclusively from the buildmaster to the worker.

To perform builds, the workers must typically obtain source code from a CVS/SVN/etc repository. Therefore they must also be able to reach the repository. The buildmaster provides instructions for performing builds, but does not provide the source code itself.

Worker Connections Buildmaster Architecture

The buildmaster consists of several pieces:

Buildmaster Architecture

Change Sources
Which create a Change object each time something is modified in the VC repository. Most ChangeSources listen for messages from a hook script of some sort. Some sources actively poll the repository on a regular basis. All Changes are fed to the schedulers.
Which decide when builds should be performed. They collect Changes into BuildRequests, which are then queued for delivery to Builders until a worker is available.
Which control exactly how each build is performed (with a series of BuildSteps, configured in a BuildFactory). Each Build is run on a single worker.
Status plugins
Which deliver information about the build results through protocols like HTTP, mail, and IRC.

Each Builder is configured with a list of Workers that it will use for its builds. These workers are expected to behave identically: the only reason to use multiple Workers for a single Builder is to provide a measure of load-balancing.

Within a single Worker, each Builder creates its own WorkerForBuilder instance. These WorkerForBuilders operate independently from each other. Each gets its own base directory to work in. It is quite common to have many Builders sharing the same worker. For example, there might be two workers: one for i386, and a second for PowerPC. There may then be a pair of Builders that do a full compile/test run, one for each architecture, and a lone Builder that creates snapshot source tarballs if the full builders complete successfully. The full builders would each run on a single worker, whereas the tarball creation step might run on either worker (since the platform doesn’t matter when creating source tarballs). In this case, the mapping would look like:

Builder(full-i386)  ->  Workers(worker-i386)
Builder(full-ppc)   ->  Workers(worker-ppc)
Builder(source-tarball) -> Workers(worker-i386, worker-ppc)

and each Worker would have two WorkerForBuilders inside it, one for a full builder, and a second for the source-tarball builder.

Once a WorkerForBuilder is available, the Builder pulls one or more BuildRequests off its incoming queue. (It may pull more than one if it determines that it can merge the requests together; for example, there may be multiple requests to build the current HEAD revision). These requests are merged into a single Build instance, which includes the SourceStamp that describes what exact version of the source code should be used for the build. The Build is then randomly assigned to a free WorkerForBuilder and the build begins.

The behaviour when BuildRequests are merged can be customized, Collapsing Build Requests. Status Delivery Architecture

The buildmaster maintains a central Status object, to which various status plugins are connected. Through this Status object, a full hierarchy of build status objects can be obtained.

Status Delivery

The configuration file controls which status plugins are active. Each status plugin gets a reference to the top-level Status object. From there they can request information on each BuilderBuildStep, and LogFile. This query-on-demand interface is used by the html.Waterfall plugin to create the main status page each time a web browser hits the main URL.

The status plugins can also subscribe to hear about new Builds as they occur: this is used by the MailNotifier to create new email messages for each recently-completed Build.

The Status object records the status of old builds on disk in the buildmaster’s base directory. This allows it to return information about historical builds.

There are also status objects that correspond to Schedulers and Workers. These allow status plugins to report information about upcoming builds, and the online/offline status of each worker.

2.1.3. Control Flow

A day in the life of the buildbot:

  • A developer commits some source code changes to the repository. A hook script or commit trigger of some sort sends information about this change to the buildmaster through one of its configured Change Sources. This notification might arrive via email, or over a network connection (either initiated by the buildmaster as it subscribes to changes, or by the commit trigger as it pushes Changes towards the buildmaster). The Change contains information about who made the change, what files were modified, which revision contains the change, and any checkin comments.
  • The buildmaster distributes this change to all of its configured schedulers. Any importantchanges cause the tree-stable-timer to be started, and the Change is added to a list of those that will go into a new Build. When the timer expires, a Build is started on each of a set of configured Builders, all compiling/testing the same source code. Unless configured otherwise, all Builds run in parallel on the various workers.
  • The Build consists of a series of Steps. Each Step causes some number of commands to be invoked on the remote worker associated with that Builder. The first step is almost always to perform a checkout of the appropriate revision from the same VC system that produced the Change. The rest generally perform a compile and run unit tests. As each Step runs, the worker reports back command output and return status to the buildmaster.
  • As the Build runs, status messages like “Build Started”, “Step Started”, “Build Finished”, etc, are published to a collection of Status Targets. One of these targets is usually the HTML Waterfalldisplay, which shows a chronological list of events, and summarizes the results of the most recent build at the top of each column. Developers can periodically check this page to see how their changes have fared. If they see red, they know that they’ve made a mistake and need to fix it. If they see green, they know that they’ve done their duty and don’t need to worry about their change breaking anything.
  • If a MailNotifier status target is active, the completion of a build will cause email to be sent to any developers whose Changes were incorporated into this Build. The MailNotifier can be configured to only send mail upon failing builds, or for builds which have just transitioned from passing to failing. Other status targets can provide similar real-time notification via different communication channels, like IRC.

2.2. Installation

2.2.1. Buildbot Components

Buildbot is shipped in two components: the buildmaster (called buildbot for legacy reasons) and the worker. The worker component has far fewer requirements, and is more broadly compatible than the buildmaster. You will need to carefully pick the environment in which to run your buildmaster, but the worker should be able to run just about anywhere.

It is possible to install the buildmaster and worker on the same system, although for anything but the smallest installation this arrangement will not be very efficient.

2.2.2. Requirements Common Requirements

At a bare minimum, you’ll need the following for both the buildmaster and a worker:


Buildbot master works with Python 2.7 or Python-3.4+. Buildbot worker works with Python 2.7, or Python 3.4+.


This should be a “normal” build of Python. Builds of Python with debugging enabled or other unusual build parameters are likely to cause incorrect behavior.


Buildbot requires Twisted-14.0.1 or later on the master, and Twisted-10.2.0 on the worker. In upcoming versions of Buildbot, a newer Twisted will also be required on the worker. As always, the most recent version is recommended.

Of course, your project’s build process will impose additional requirements on the workers. These hosts must have all the tools necessary to compile and test your project’s source code.

Windows Support

Buildbot - both master and worker - runs well natively on Windows. The worker runs well on Cygwin, but because of problems with SQLite on Cygwin, the master does not.

Buildbot’s windows testing is limited to the most recent Twisted and Python versions. For best results, use the most recent available versions of these libraries on Windows.


Twisted requires PyWin32 in order to spawn processes on Windows. Buildmaster Requirements

Note that all of these requirements aside from SQLite can easily be installed from the Python package repository, PyPI.


Buildbot requires a database to store its state, and by default uses SQLite. Version 3.7.0 or higher is recommended, although Buildbot will run down to 3.6.16 – at the risk of “Database is locked” errors. The minimum version is 3.4.0, below which parallel database queries and schema introspection fail.

Please note that Python ships with sqlite3 by default since Python 2.6.

If you configure a different database engine, then SQLite is not required. however note that Buildbot’s own unit tests require SQLite.


Buildbot requires Jinja version 2.1 or higher.

Jinja2 is a general purpose templating language and is used by Buildbot to generate the HTML output.


Buildbot requires SQLAlchemy version 0.8.0 or higher. SQLAlchemy allows Buildbot to build database schemas and queries for a wide variety of database systems.


Buildbot requires SQLAlchemy-Migrate version 0.9.0 or higher. Buildbot uses SQLAlchemy-Migrate to manage schema upgrades from version to version.


Buildbot requires Python-Dateutil in version 1.5 or higher (the last version to support Python-2.x). This is a small, pure-Python library.


The master requires Autobahn version 0.16.0 or higher with Python 2.7.

2.2.3. Installing the code The Buildbot Packages

Buildbot comes in several parts: buildbot (the buildmaster), buildbot-worker (the worker), buildbot-www, and several web plugins such as buildbot-waterfall-view.

The worker and buildmaster can be installed individually or together. The base web (buildbot.www) and web plugins are required to run a master with a web interface (the common configuration). Installation From PyPI

The preferred way to install Buildbot is using pip. For the master:

pip install buildbot

and for the worker:

pip install buildbot-worker

When using pip to install instead of distribution specific package managers, e.g. via apt-get or ports, it is simpler to choose exactly which version one wants to use. It may however be easier to install via distribution specific package mangers but note that they may provide an earlier version than what is available via pip.

If you plan to use TLS or SSL in master configuration (e.g. to fetch resources over HTTPS using twisted.web.client), you need to install Buildbot with tls extras:

pip install buildbot[tls] Installation From Tarballs

Buildbot master and buildbot-worker are installed using the standard Python distutils process. For either component, after unpacking the tarball, the process is:

python build
python install

where the install step may need to be done as root. This will put the bulk of the code in somewhere like /usr/lib/pythonx.y/site-packages/buildbot. It will also install the buildbot command-line tool in /usr/bin/buildbot.

If the environment variable $NO_INSTALL_REQS is set to 1, then will not try to install Buildbot’s requirements. This is usually only useful when building a Buildbot package.

To test this, shift to a different directory (like /tmp), and run:

buildbot --version
# or
buildbot-worker --version

If it shows you the versions of Buildbot and Twisted, the install went ok. If it says “no such command” or it gets an ImportError when it tries to load the libraries, then something went wrong. pydoc buildbotis another useful diagnostic tool.

Windows users will find these files in other places. You will need to make sure that Python can find the libraries, and will probably find it convenient to have buildbot on your PATH. Installation in a Virtualenv

If you cannot or do not wish to install the buildbot into a site-wide location like /usr or /usr/local, you can also install it into the account’s home directory or any other location using a tool like virtualenv. Running Buildbot’s Tests (optional)

If you wish, you can run the buildbot unit test suite. First, ensure you have the mock Python module installed from PyPI. You must not be using a Python wheels packaged version of Buildbot or have specified the bdist_wheel command when building. The test suite is not included with the PyPi packaged version. This module is not required for ordinary Buildbot operation - only to run the tests. Note that this is not the same as the Fedora mock package!

You can check with

python -mmock

Then, run the tests:

PYTHONPATH=. trial buildbot.test
# or
PYTHONPATH=. trial buildbot_worker.test

Nothing should fail, although a few might be skipped.

If any of the tests fail for reasons other than a missing mock, you should stop and investigate the cause before continuing the installation process, as it will probably be easier to track down the bug early. In most cases, the problem is incorrectly installed Python modules or a badly configured PYTHONPATH. This may be a good time to contact the Buildbot developers for help.

2.2.4. Buildmaster Setup Creating a buildmaster

As you learned earlier (System Architecture), the buildmaster runs on a central host (usually one that is publicly visible, so everybody can check on the status of the project), and controls all aspects of the buildbot system

You will probably wish to create a separate user account for the buildmaster, perhaps named buildmaster. Do not run the buildmaster as root!

You need to choose a directory for the buildmaster, called the basedir. This directory will be owned by the buildmaster. It will contain configuration, the database, and status information - including logfiles. On a large buildmaster this directory will see a lot of activity, so it should be on a disk with adequate space and speed.

Once you’ve picked a directory, use the buildbot create-master command to create the directory and populate it with startup files:

buildbot create-master -r basedir

You will need to create a configuration file before starting the buildmaster. Most of the rest of this manual is dedicated to explaining how to do this. A sample configuration file is placed in the working directory, named master.cfg.sample, which can be copied to master.cfg and edited to suit your purposes.

(Internal details: This command creates a file named buildbot.tac that contains all the state necessary to create the buildmaster. Twisted has a tool called twistd which can use this .tac file to create and launch a buildmaster instance. Twistd takes care of logging and daemonization (running the program in the background). /usr/bin/buildbot is a front end which runs twistd for you.)

Your master will need a database to store the various information about your builds, and its configuration. By default, the sqlite3 backend will be used. This needs no configuration, neither extra software. All information will be stored in the file state.sqlite. Buildbot however supports multiple backends. See Using A Database Server for more options.

Buildmaster Options

This section lists options to the create-master command. You can also type buildbot create-master --help for an up-to-the-moment summary.


This option will allow to re-use an existing directory.


This disables internal worker log management mechanism. With this option worker does not override the default logfile name and its behaviour giving a possibility to control those with command-line options of twistd daemon.


This creates a “relocatable” buildbot.tac, which uses relative paths instead of absolute paths, so that the buildmaster directory can be moved about.


The name of the configuration file to use. This configuration file need not reside in the buildmaster directory.


This is the size in bytes when to rotate the Twisted log files. The default is 10MiB.


This is the number of log rotations to keep around. You can either specify a number or None to keep all twistd.log files around. The default is 10.


The database that the Buildmaster should use. Note that the same value must be added to the configuration file. Upgrading an Existing Buildmaster

If you have just installed a new version of the Buildbot code, and you have buildmasters that were created using an older version, you’ll need to upgrade these buildmasters before you can use them. The upgrade process adds and modifies files in the buildmaster’s base directory to make it compatible with the new code.

buildbot upgrade-master basedir

This command will also scan your master.cfg file for incompatibilities (by loading it and printing any errors or deprecation warnings that occur). Each buildbot release tries to be compatible with configurations that worked cleanly (i.e. without deprecation warnings) on the previous release: any functions or classes that are to be removed will first be deprecated in a release, to give you a chance to start using the replacement.

The upgrade-master command is idempotent. It is safe to run it multiple times. After each upgrade of the buildbot code, you should use upgrade-master on all your buildmasters.

In general, Buildbot workers and masters can be upgraded independently, although some new features will not be available, depending on the master and worker versions.

Beyond this general information, read all of the sections below that apply to versions through which you are upgrading.

Version-specific Notes

Upgrading from Buildbot-0.8.x to Buildbot-0.9.x

See Upgrading to Nine for a guide to upgrading from 0.8.x to 0.9.x

Upgrading a Buildmaster to Buildbot-0.7.6

The 0.7.6 release introduced the public_html/ directory, which contains index.html and other files served by the WebStatus and Waterfall status displays. The upgrade-master command will create these files if they do not already exist. It will not modify existing copies, but it will write a new copy in e.g. if the new version differs from the version that already exists.

Upgrading a Buildmaster to Buildbot-0.8.0

Buildbot-0.8.0 introduces a database backend, which is SQLite by default. The upgrade-mastercommand will automatically create and populate this database with the changes the buildmaster has seen. Note that, as of this release, build history is not contained in the database, and is thus not migrated.

Upgrading into a non-SQLite database

If you are not using sqlite, you will need to add an entry into your master.cfg to reflect the database version you are using. The upgrade process does not edit your master.cfg for you. So something like:

# for using mysql:
c['db_url'] = 'mysql://bbuser:<password>@localhost/buildbot'

Once the parameter has been added, invoke upgrade-master. This will extract the DB url from your configuration file.

buildbot upgrade-master

See Database Specification for more options to specify a database.

2.2.5. Worker Setup Creating a worker

Typically, you will be adding a worker to an existing buildmaster, to provide additional architecture coverage. The buildbot administrator will give you several pieces of information necessary to connect to the buildmaster. You should also be somewhat familiar with the project being tested, so you can troubleshoot build problems locally.

The buildbot exists to make sure that the project’s stated how to build it process actually works. To this end, the worker should run in an environment just like that of your regular developers. Typically the project build process is documented somewhere (READMEINSTALL, etc), in a document that should mention all library dependencies and contain a basic set of build instructions. This document will be useful as you configure the host and account in which the worker runs.

Here’s a good checklist for setting up a worker:

  1. Set up the account

It is recommended (although not mandatory) to set up a separate user account for the worker. This account is frequently named buildbot or worker. This serves to isolate your personal working environment from that of the worker’s, and helps to minimize the security threat posed by letting possibly-unknown contributors run arbitrary code on your system. The account should have a minimum of fancy init scripts.

  1. Install the buildbot code

Follow the instructions given earlier (Installing the code). If you use a separate worker account, and you didn’t install the buildbot code to a shared location, then you will need to install it with --home=~ for each account that needs it.

  1. Set up the host

Make sure the host can actually reach the buildmaster. Usually the buildmaster is running a status webserver on the same machine, so simply point your web browser at it and see if you can get there. Install whatever additional packages or libraries the project’s INSTALL document advises. (or not: if your worker is supposed to make sure that building without optional libraries still works, then don’t install those libraries.)

Again, these libraries don’t necessarily have to be installed to a site-wide shared location, but they must be available to your build process. Accomplishing this is usually very specific to the build process, so installing them to /usr or /usr/local is usually the best approach.

  1. Test the build process

Follow the instructions in the INSTALL document, in the worker’s account. Perform a full CVS (or whatever) checkout, configure, make, run tests, etc. Confirm that the build works without manual fussing. If it doesn’t work when you do it by hand, it will be unlikely to work when the buildbot attempts to do it in an automated fashion.

  1. Choose a base directory

This should be somewhere in the worker’s account, typically named after the project which is being tested. The worker will not touch any file outside of this directory. Something like ~/Buildbot or ~/Workers/fooproject is appropriate.

  1. Get the buildmaster host/port, botname, and password

When the buildbot admin configures the buildmaster to accept and use your worker, they will provide you with the following pieces of information:

  1. Create the worker

Now run the ‘worker’ command as follows:


This will create the base directory and a collection of files inside, including the buildbot.tac file that contains all the information you passed to the buildbot command.

  1. Fill in the hostinfo files

When it first connects, the worker will send a few files up to the buildmaster which describe the host that it is running on. These files are presented on the web status display so that developers have more information to reproduce any test failures that are witnessed by the buildbot. There are sample files in the info subdirectory of the buildbot’s base directory. You should edit these to correctly describe you and your host.

BASEDIR/info/admin should contain your name and email address. This is the worker adminaddress, and will be visible from the build status page (so you may wish to munge it a bit if address-harvesting spambots are a concern).

BASEDIR/info/host should be filled with a brief description of the host: OS, version, memory size, CPU speed, versions of relevant libraries installed, and finally the version of the buildbot code which is running the worker.

The optional BASEDIR/info/access_uri can specify a URI which will connect a user to the machine. Many systems accept ssh://hostname URIs for this purpose.

If you run many workers, you may want to create a single ~worker/info file and share it among all the workers with symlinks.

Worker Options

There are a handful of options you might want to use when creating the worker with the buildbot-worker create-worker <options> DIR <params> command. You can type buildbot-worker create-worker --help for a summary. To use these, just include them on the buildbot-worker create-worker command line, like this

buildbot-worker create-worker --umask=0o22 ~/worker {myworkername} {mypasswd}

This disables internal worker log management mechanism. With this option worker does not override the default logfile name and its behaviour giving a possibility to control those with command-line options of twistd daemon.


This is a string (generally an octal representation of an integer) which will cause the worker process’ umask value to be set shortly after initialization. The twistd daemonization utility forces the umask to 077 at startup (which means that all files created by the worker or its child processes will be unreadable by any user other than the worker account). If you want build products to be readable by other accounts, you can add --umask=022 to tell the worker to fix the umask after twistd clobbers it. If you want build products to be writable by other accounts too, use --umask=000, but this is likely to be a security problem.


This is a number that indicates how frequently keepalive messages should be sent from the worker to the buildmaster, expressed in seconds. The default (600) causes a message to be sent to the buildmaster at least once every 10 minutes. To set this to a lower value, use e.g. --keepalive=120.

If the worker is behind a NAT box or stateful firewall, these messages may help to keep the connection alive: some NAT boxes tend to forget about a connection if it has not been used in a while. When this happens, the buildmaster will think that the worker has disappeared, and builds will time out. Meanwhile the worker will not realize than anything is wrong.


This is a number that indicates the maximum amount of time the worker will wait between connection attempts, expressed in seconds. The default (300) causes the worker to wait at most 5 minutes before trying to connect to the buildmaster again.


This is a number that indicates the maximum number of time the worker will make connection attempts. After that amount, the worker process will stop. This option is useful for Latent Workers to avoid consuming resources in case of misconfiguration or master failure.

For VM based latent workers, the user is responsible for halting the system when Buildbot worker has exited. This feature is heavily OS dependent, and cannot be managed by Buildbot worker. For example with systemd, one can add ExecStopPost=shutdown now to the Buildbot worker service unit configuration.


This is the size in bytes when to rotate the Twisted log files.


This is the number of log rotations to keep around. You can either specify a number or None to keep all twistd.log files around. The default is 10.


Can also be passed directly to the Worker constructor in buildbot.tac. If set, it allows the worker to initiate a graceful shutdown, meaning that it will ask the master to shut down the worker when the current build, if any, is complete.

Setting allow_shutdown to file will cause the worker to watch shutdown.stamp in basedir for updates to its mtime. When the mtime changes, the worker will request a graceful shutdown from the master. The file does not need to exist prior to starting the worker.

Setting allow_shutdown to signal will set up a SIGHUP handler to start a graceful shutdown. When the signal is received, the worker will request a graceful shutdown from the master.

The default value is None, in which case this feature will be disabled.

Both master and worker must be at least version 0.8.3 for this feature to work.

Other Worker Configuration

This represents the encoding that buildbot should use when converting unicode commandline arguments into byte strings in order to pass to the operating system when spawning new processes.

The default value is what Python’s sys.getfilesystemencoding returns, which on Windows is ‘mbcs’, on Mac OSX is ‘utf-8’, and on Unix depends on your locale settings.

If you need a different encoding, this can be changed in your worker’s buildbot.tac file by adding a unicode_encoding argument to the Worker constructor.

s = Worker(buildmaster_host, port, workername, passwd, basedir,
           keepalive, usepty, umask=umask, maxdelay=maxdelay,
           unicode_encoding='utf-8', allow_shutdown='signal') Upgrading an Existing Worker
Version-specific Notes

During project lifetime worker has transitioned over few states:

  1. Before Buildbot version 0.8.1 worker were integral part of buildbot package distribution.
  2. Starting from Buildbot version 0.8.1 worker were extracted from buildbot package to buildbot-slave package.
  3. Starting from Buildbot version 0.9.0 the buildbot-slave package was renamed to buildbot-worker.

Upgrading a Worker to buildbot-slave 0.8.1

Before Buildbot version 0.8.1, the Buildbot master and worker were part of the same distribution. As of version 0.8.1, the worker is a separate distribution.

As of this release, you will need to install buildbot-slave to run a worker.

Any automatic startup scripts that had run buildbot start for previous versions should be changed to run buildslave start instead.

If you are running a version later than 0.8.1, then you can skip the remainder of this section: the upgrade-slave command will take care of this. If you are upgrading directly to 0.8.1, read on.

The existing buildbot.tac for any workers running older versions will need to be edited or replaced. If the loss of cached worker state (e.g., for Source steps in copy mode) is not problematic, the easiest solution is to simply delete the worker directory and re-run buildslave create-slave.

If deleting the worker directory is problematic, the change to buildbot.tac is simple. On line 3, replace:

from import BuildSlave


from import BuildSlave

After this change, the worker should start as usual.

Upgrading from 0.8.1 to the latest 0.8.* version of buildbot-slave

If you have just installed a new version of Buildbot-slave, you may need to take some steps to upgrade it. If you are upgrading to version 0.8.2 or later, you can run

buildslave upgrade-slave /path/to/worker/dir

Upgrading from the latest version of buildbot-slave to buildbot-worker

If the loss of cached worker state (e.g., for Source steps in copy mode) is not problematic, the easiest solution is to simply delete the worker directory and re-run buildbot-worker create-worker.

If deleting the worker directory is problematic, you can change buildbot.tac in the following way:

  1. Replace:

    from import BuildSlave


    from import Worker
  2. Replace:

    application = service.Application('buildslave')


    application = service.Application('buildbot-worker')
  3. Replace:

    s = BuildSlave(buildmaster_host, port, slavename, passwd, basedir,
                   keepalive, usepty, umask=umask, maxdelay=maxdelay,
                   numcpus=numcpus, allow_shutdown=allow_shutdown)


    s = Worker(buildmaster_host, port, slavename, passwd, basedir,
               keepalive, umask=umask, maxdelay=maxdelay,
               numcpus=numcpus, allow_shutdown=allow_shutdown)

See Transition to “Worker” Terminology for details of changes in version Buildbot 0.9.0.

2.2.6. Next Steps Launching the daemons

Both the buildmaster and the worker run as daemon programs. To launch them, pass the working directory to the buildbot and buildbot-worker commands, as appropriate:

# start a master
buildbot start [ BASEDIR ]
# start a worker
buildbot-worker start [ WORKER_BASEDIR ]

The BASEDIR is option and can be omitted if the current directory contains the buildbot configuration (the buildbot.tac file).

buildbot start

This command will start the daemon and then return, so normally it will not produce any output. To verify that the programs are indeed running, look for a pair of files named twistd.log and twistd.pidthat should be created in the working directory. contains the process ID of the newly-spawned daemon.

When the worker connects to the buildmaster, new directories will start appearing in its base directory. The buildmaster tells the worker to create a directory for each Builder which will be using that worker. All build operations are performed within these directories: CVS checkouts, compiles, and tests.

Once you get everything running, you will want to arrange for the buildbot daemons to be started at boot time. One way is to use cron, by putting them in a @reboot crontab entry [1]

@reboot buildbot start [ BASEDIR ]

When you run crontab to set this up, remember to do it as the buildmaster or worker account! If you add this to your crontab when running as your regular account (or worse yet, root), then the daemon will run as the wrong user, quite possibly as one with more authority than you intended to provide.

It is important to remember that the environment provided to cron jobs and init scripts can be quite different that your normal runtime. There may be fewer environment variables specified, and the PATHmay be shorter than usual. It is a good idea to test out this method of launching the worker by using a cron job with a time in the near future, with the same command, and then check twistd.log to make sure the worker actually started correctly. Common problems here are for /usr/local or ~/bin to not be on your PATH, or for PYTHONPATH to not be set correctly. Sometimes HOME is messed up too.

Some distributions may include conveniences to make starting buildbot at boot time easy. For instance, with the default buildbot package in Debian-based distributions, you may only need to modify /etc/default/buildbot (see also /etc/init.d/buildbot, which reads the configuration in /etc/default/buildbot).

Buildbot also comes with its own init scripts that provide support for controlling multi-worker and multi-master setups (mostly because they are based on the init script from the Debian package). With a little modification these scripts can be used both on Debian and RHEL-based distributions and may thus prove helpful to package maintainers who are working on buildbot (or those that haven’t yet split buildbot into master and worker packages).

# install as /etc/default/buildbot-worker
#         or /etc/sysconfig/buildbot-worker

# install as /etc/default/buildmaster
#         or /etc/sysconfig/buildmaster

# install as /etc/init.d/buildbot-worker

# install as /etc/init.d/buildmaster

# ... and tell sysvinit about them
chkconfig buildmaster reset
# ... or
update-rc.d buildmaster defaults Logfiles

While a buildbot daemon runs, it emits text to a logfile, named twistd.log. A command like tail -ftwistd.log is useful to watch the command output as it runs.

The buildmaster will announce any errors with its configuration file in the logfile, so it is a good idea to look at the log at startup time to check for any problems. Most buildmaster activities will cause lines to be added to the log. Shutdown

To stop a buildmaster or worker manually, use:

buildbot stop [ BASEDIR ]
# or
buildbot-worker stop [ WORKER_BASEDIR ]

This simply looks for the file and kills whatever process is identified within.

At system shutdown, all processes are sent a SIGKILL. The buildmaster and worker will respond to this by shutting down normally.

The buildmaster will respond to a SIGHUP by re-reading its config file. Of course, this only works on Unix-like systems with signal support, and won’t work on Windows. The following shortcut is available:

buildbot reconfig [ BASEDIR ]

When you update the Buildbot code to a new release, you will need to restart the buildmaster and/or worker before it can take advantage of the new code. You can do a buildbot stop BASEDIR and buildbotstart BASEDIR in quick succession, or you can use the restart shortcut, which does both steps for you:

buildbot restart [ BASEDIR ]

Workers can similarly be restarted with:

buildbot-worker restart [ BASEDIR ]

There are certain configuration changes that are not handled cleanly by buildbot reconfig. If this occurs, buildbot restart is a more robust tool to fully switch over to the new configuration.

buildbot restart may also be used to start a stopped Buildbot instance. This behaviour is useful when writing scripts that stop, start and restart Buildbot.

A worker may also be gracefully shutdown from the web UI. This is useful to shutdown a worker without interrupting any current builds. The buildmaster will wait until the worker is finished all its current builds, and will then tell the worker to shutdown.

[1] This @reboot syntax is understood by Vixie cron, which is the flavor usually provided with Linux systems. Other unices may have a cron that doesn’t understand @reboot

2.3. Concepts

This chapter defines some of the basic concepts that the Buildbot uses. You’ll need to understand how the Buildbot sees the world to configure it properly.

2.3.1. Source Stamps

Buildbot uses the concept of source stamp set to identify exact source code that needs to be built for a certain project. A source stamp set is a collection of one or more source stamps.

source stamp is a collection of information needed to identify a particular version of code on a certain codebase. This information most often is a revision and possibly a branch.

codebase is a collection of related files and their history tracked as a unit by version control systems. A single codebase may appear in multiple repositories which themselves are identified by URLs. For example, and both contain the Firefox codebase, although not exactly the same code.

project is corresponds to a set of one or more codebases that together may be built and produce some end artifact. For example, a company may build several applications based on the same core library. The “app” codebase and the “core” codebase are in separate repositories, but are compiled together and constitute a single project. Changes to either codebase should cause a rebuild of the application.

revision is an identifier used by most version control systems to uniquely specify a particular version of the source code. Sometimes in order to do that a revision may make sense only if used combination with a branch.

To sum up the above, to build a project, Buildbot needs to know exactly which version of each codebase it should build. It uses a source stamp to do so for each codebase, each of which assigns informs Buildbot that it should use a specific revision from that codebase. Collectively these source stamps are called source stamp set for each project.

Source Stamp Sets

2.3.2. Version Control Systems

Buildbot supports a significant number of version control systems, so it treats them abstractly.

For purposes of deciding when to perform builds, Buildbot’s change sources monitor repositories, and represent any updates to those repositories as changes. These change sources fall broadly into two categories: pollers which periodically check the repository for updates; and hooks, where the repository is configured to notify Buildbot whenever an update occurs. For more information see Change Sources and Changes and How Different VC Systems Specify Sources.

When it comes time to actually perform a build, a scheduler prepares a source stamp set, as described above, based on its configuration. When the build begins, one or more source steps use the information in the source stamp set to actually check out the source code, using the normal VCS commands.

2.3.3. Changes

Change is an abstract way Buildbot uses to represent a single change to the source files performed by a developer. In version control systems that support the notion of atomic check-ins a change represents a changeset or commit.

Change comprises of the following information:

  • the developer that is responsible for the change
  • the list of files that the change added, removed or modified
  • the message of the commit
  • the repository, the codebase and the project that the change corresponds to
  • the revision and the branch of the commit

2.3.4. Scheduling Builds

Each Buildmaster has a set of scheduler objects, each of which gets a copy of every incoming Change. The Schedulers are responsible for deciding when Builds should be run. Some Buildbot installations might have a single scheduler, while others may have several, each for a different purpose.

For example, a quick scheduler might exist to give immediate feedback to developers, hoping to catch obvious problems in the code that can be detected quickly. These typically do not run the full test suite, nor do they run on a wide variety of platforms. They also usually do a VC update rather than performing a brand-new checkout each time.

A separate full scheduler might run more comprehensive tests, to catch more subtle problems. configured to run after the quick scheduler, to give developers time to commit fixes to bugs caught by the quick scheduler before running the comprehensive tests. This scheduler would also feed multiple Builders.

Many schedulers can be configured to wait a while after seeing a source-code change - this is the tree stable timer. The timer allows multiple commits to be “batched” together. This is particularly useful in distributed version control systems, where a developer may push a long sequence of changes all at once. To save resources, it’s often desirable only to test the most recent change.

Schedulers can also filter out the changes they are interested in, based on a number of criteria. For example, a scheduler that only builds documentation might skip any changes that do not affect the documentation. Schedulers can also filter on the branch to which a commit was made.

There is some support for configuring dependencies between builds - for example, you may want to build packages only for revisions which pass all of the unit tests. This support is under active development in Buildbot, and is referred to as “build coordination”.

Periodic builds (those which are run every N seconds rather than after new Changes arrive) are triggered by a special Periodic scheduler.

Each scheduler creates and submits BuildSet objects to the BuildMaster, which is then responsible for making sure the individual BuildRequests are delivered to the target Builders.

Scheduler instances are activated by placing them in the schedulers list in the buildmaster config file. Each scheduler must have a unique name.

2.3.5. BuildSets

BuildSet is the name given to a set of Builds that all compile/test the same version of the tree on multiple Builders. In general, all these component Builds will perform the same sequence of Steps, using the same source code, but on different platforms or against a different set of libraries.

The BuildSet is tracked as a single unit, which fails if any of the component Builds have failed, and therefore can succeed only if all of the component Builds have succeeded. There are two kinds of status notification messages that can be emitted for a BuildSet: the firstFailure type (which fires as soon as we know the BuildSet will fail), and the Finished type (which fires once the BuildSet has completely finished, regardless of whether the overall set passed or failed).

BuildSet is created with set of one or more source stamp tuples of (branch, revision, changes,patch), some of which may be None, and a list of Builders on which it is to be run. They are then given to the BuildMaster, which is responsible for creating a separate BuildRequest for each Builder.

There are a couple of different likely values for the SourceStamp:

(revision=None, changes=CHANGES, patch=None)
This is a SourceStamp used when a series of Changes have triggered a build. The VC step will attempt to check out a tree that contains CHANGES (and any changes that occurred before CHANGES, but not any that occurred after them.)
(revision=None, changes=None, patch=None)
This builds the most recent code on the default branch. This is the sort of SourceStamp that would be used on a Build that was triggered by a user request, or a Periodic scheduler. It is also possible to configure the VC Source Step to always check out the latest sources rather than paying attention to the Changes in the SourceStamp, which will result in same behavior as this.
(branch=BRANCH, revision=None, changes=None, patch=None)
This builds the most recent code on the given BRANCH. Again, this is generally triggered by a user request or a Periodic scheduler.
(revision=REV, changes=None, patch=(LEVELDIFFSUBDIR_ROOT))
This checks out the tree at the given revision REV, then applies a patch (using patch -pLEVEL <DIFF) from inside the relative directory SUBDIR_ROOT. Item SUBDIR_ROOT is optional and defaults to the builder working directory. The try command creates this kind of SourceStamp. If patch is None, the patching step is bypassed.

The buildmaster is responsible for turning the BuildSet into a set of BuildRequest objects and queueing them on the appropriate Builders.

2.3.6. BuildRequests

BuildRequest is a request to build a specific set of source code (specified by one or more source stamps) on a single Builder. Each Builder runs the BuildRequest as soon as it can (i.e. when an associated worker becomes free). BuildRequests are prioritized from oldest to newest, so when a worker becomes free, the Builder with the oldest BuildRequest is run.

The BuildRequest contains one SourceStamp specification per codebase. The actual process of running the build (the series of Steps that will be executed) is implemented by the Build object. In the future this might be changed, to have the Build define what gets built, and a separate BuildProcess (provided by the Builder) to define how it gets built.

The BuildRequest may be mergeable with other compatible BuildRequests. Builds that are triggered by incoming Changes will generally be mergeable. Builds that are triggered by user requests are generally not, unless they are multiple requests to build the latest sources of the same branch. A merge of buildrequests is performed per codebase, thus on changes having the same codebase.

2.3.7. Builders

Builder handles the process of scheduling work to workers. Each Builder is responsible for a certain type of build, which usually consist of identical or very similar sequence of steps.

The class serves as a kind of queue for that particular type of build. In general, each Builder runs independently, but it’s possible to constrain the behavior of Builders using various kinds of interlocks.

Each builder is a long-lived object which controls a sequence of Builds. A Builder is created when the config file is first parsed, and lives forever (or rather until it is removed from the config file). It mediates the connections to the workers that do all the work, and is responsible for creating the Buildobjects - Builds.

Each builder gets a unique name, and the path name of a directory where it gets to do all its work. This path is used in two ways. On the buildmaster-side a directory is created for keeping status information. On the worker-side a directory is created where the actual checkout, compile and test commands are executed.

2.3.8. Build Factories

A builder also has a BuildFactory, which is responsible for creating new Build instances: because the Build instance is what actually performs each build, choosing the BuildFactory is the way to specify what happens each time a build is done (Builds).

2.3.9. Workers

Workers corresponds to an environment where builds are executed. A single physical machine that must run at least one Workers in order for Buildbot to be able to utilize it for running builds. Multiple Workers may run on a single machine to provide different environments that can reuse the same hardware by means of containers or virtual machines.

Each builder is associated with one or more Workers. For example, a builder which is used to perform macOS builds (as opposed to Linux or Windows builds) should naturally be associated with a Mac worker.

If multiple workers are available for any given builder, you will have some measure of redundancy: in case one worker goes offline, the others can still keep the Builder working. In addition, multiple workers will allow multiple simultaneous builds for the same Builder, which might be useful if you have a lot of forced or try builds taking place.

Ideally, each Worker that is configured for a builder should be identical. Otherwise build or test failures will be dependent on which worker the build is ran and this will complicate investigation of failures.

2.3.10. Builds

Build is a single compile or test run of a particular version of the source code, and is comprised of a series of steps. The steps may be arbitrary. For example, for compiled software a build generally consists of the checkout, configure, make, and make check sequence. For interpreted projects like Python modules, a build is generally a checkout followed by an invocation of the bundled test suite.

BuildFactory describes the steps a build will perform. The builder which starts a build uses its configured build factory to determine the build’s steps.

2.3.11. Users

Buildbot has a somewhat limited awareness of users. It assumes the world consists of a set of developers, each of whom can be described by a couple of simple attributes. These developers make changes to the source code, causing builds which may succeed or fail.

Users also may have different levels of authorization when issuing Buildbot commands, such as forcing a build from the web interface or from an IRC channel.

Each developer is primarily known through the source control system. Each Change object that arrives is tagged with a who field that typically gives the account name (on the repository machine) of the user responsible for that change. This string is displayed on the HTML status pages and in each Build’s blamelist.

To do more with the User than just refer to them, this username needs to be mapped into an address of some sort. The responsibility for this mapping is left up to the status module which needs the address. In the future, the responsibility for managing users will be transferred to User Objects.

The who fields in git Changes are used to create User Objects, which allows for more control and flexibility in how Buildbot manages users. User Objects

User Objects allow Buildbot to better manage users throughout its various interactions with users (see Change Sources and Changes and Reporters). The User Objects are stored in the Buildbot database and correlate the various attributes that a user might have: irc, Git, etc.


Incoming Changes all have a who attribute attached to them that specifies which developer is responsible for that Change. When a Change is first rendered, the who attribute is parsed and added to the database if it doesn’t exist or checked against an existing user. The who attribute is formatted in different ways depending on the version control system that the Change came from.

who attributes take the form Full Name <Email>.
who attributes are of the form Username.
who attributes are free-form strings, but usually adhere to similar conventions as git attributes (Full Name <Email>).
who attributes are of the form Username.
who attributes contain an Email and may also include a Full Name like git attributes.
who attributes are free-form strings like hg, and can include a UsernameEmail, and/or Full Name.

For managing users manually, use the buildbot user command, which allows you to add, remove, update, and show various attributes of users in the Buildbot database (see Command-line Tool).


Correlating the various bits and pieces that Buildbot views as users also means that one attribute of a user can be translated into another. This provides a more complete view of users throughout Buildbot.

One such use is being able to find email addresses based on a set of Builds to notify users through the MailNotifier. This process is explained more clearly in Email Addresses.

Another way to utilize User Objects is through UsersAuth for web authentication. To use UsersAuth, you need to set a bb_username and bb_password via the buildbot user command line tool to check against. The password will be encrypted before storing in the database along with other user attributes. Doing Things With Users

Each change has a single user who is responsible for it. Most builds have a set of changes: the build generally represents the first time these changes have been built and tested by the Buildbot. The build has a blamelist that is the union of the users responsible for all the build’s changes. If the build was created by a Try Schedulers this list will include the submitter of the try job, if known.

The build provides a list of users who are interested in the build – the interested users. Usually this is equal to the blamelist, but may also be expanded, e.g., to include the current build sherrif or a module’s maintainer.

If desired, the buildbot can notify the interested users until the problem is resolved. Email Addresses

The MailNotifier is a status target which can send email about the results of each build. It accepts a static list of email addresses to which each message should be delivered, but it can also be configured to send mail to the Build’s Interested Users. To do this, it needs a way to convert User names into email addresses.

For many VC systems, the User Name is actually an account name on the system which hosts the repository. As such, turning the name into an email address is a simple matter of appending Some projects use other kinds of mappings (for example the preferred email address may be at despite the repository host being named, and some VC systems have full separation between the concept of a user and that of an account on the repository host (like Perforce). Some systems (like Git) put a full contact email address in every change.

To convert these names to addresses, the MailNotifier uses an EmailLookup object. This provides a getAddress method which accepts a name and (eventually) returns an address. The default MailNotifier module provides an EmailLookup which simply appends a static string, configurable when the notifier is created. To create more complex behaviors (perhaps using an LDAP lookup, or using finger on a central host to determine a preferred address for the developer), provide a different object as the lookup argument.

If an EmailLookup object isn’t given to the MailNotifier, the MailNotifier will try to find emails through User Objects. This will work the same as if an EmailLookup object was used if every user in the Build’s Interested Users list has an email in the database for them. If a user whose change led to a Build doesn’t have an email attribute, that user will not receive an email. If extraRecipients is given, those users are still sent mail when the EmailLookup object is not specified.

In the future, when the Problem mechanism has been set up, the Buildbot will need to send mail to arbitrary Users. It will do this by locating a MailNotifier-like object among all the buildmaster’s status targets, and asking it to send messages to various Users. This means the User-to-address mapping only has to be set up once, in your MailNotifier, and every email message the buildbot emits will take advantage of it. IRC Nicknames

Like MailNotifier, the buildbot.status.words.IRC class provides a status target which can announce the results of each build. It also provides an interactive interface by responding to online queries posted in the channel or sent as private messages.

In the future, the buildbot can be configured to map User names to IRC nicknames, to watch for the recent presence of these nicknames, and to deliver build status messages to the interested parties. Like MailNotifier does for email addresses, the IRC object will have an IRCLookup which is responsible for nicknames. The mapping can be set up statically, or it can be updated by online users themselves (by claiming a username with some kind of buildbot: i am user warner commands).

Once the mapping is established, the rest of the buildbot can ask the IRC object to send messages to various users. It can report on the likelihood that the user saw the given message (based upon how long the user has been inactive on the channel), which might prompt the Problem Hassler logic to send them an email message instead.

These operations and authentication of commands issued by particular nicknames will be implemented in User Objects.

2.3.12. Build Properties

Each build has a set of Build Properties, which can be used by its build steps to modify their actions. These properties, in the form of key-value pairs, provide a general framework for dynamically altering the behavior of a build based on its circumstances.

Properties form a simple kind of variable in a build. Some properties are set when the build starts, and properties can be changed as a build progresses – properties set or changed in one step may be accessed in subsequent steps. Property values can be numbers, strings, lists, or dictionaries - basically, anything that can be represented in JSON.

Properties are very flexible, and can be used to implement all manner of functionality. Here are some examples:

Most Source steps record the revision that they checked out in the got_revision property. A later step could use this property to specify the name of a fully-built tarball, dropped in an easily-accessible directory for later testing.


In builds with more than one codebase, the got_revision property is a dictionary, keyed by codebase.

Some projects want to perform nightly builds as well as building in response to committed changes. Such a project would run two schedulers, both pointing to the same set of builders, but could provide an is_nightly property so that steps can distinguish the nightly builds, perhaps to run more resource-intensive tests.

Some projects have different build processes on different systems. Rather than create a build factory for each worker, the steps can use worker properties to identify the unique aspects of each worker and adapt the build process dynamically.

2.3.13. Multiple-Codebase Builds

What if an end-product is composed of code from several codebases? Changes may arrive from different repositories within the tree-stable-timer period. Buildbot will not only use the source-trees that contain changes but also needs the remaining source-trees to build the complete product.

For this reason a Scheduler can be configured to base a build on a set of several source-trees that can (partly) be overridden by the information from incoming Changes.

As described above, the source for each codebase is identified by a source stamp, containing its repository, branch and revision. A full build set will specify a source stamp set describing the source to use for each codebase.

Configuring all of this takes a coordinated approach. A complete multiple repository configuration consists of:

codebase generator

Every relevant change arriving from a VC must contain a codebase. This is done by a codebaseGenerator that is defined in the configuration. Most generators examine the repository of a change to determine its codebase, using project-specific rules.

some schedulers

Each scheduler has to be configured with a set of all required codebases to build a product. These codebases indicate the set of required source-trees. In order for the scheduler to be able to produce a complete set for each build, the configuration can give a default repository, branch, and revision for each codebase. When a scheduler must generate a source stamp for a codebase that has received no changes, it applies these default values.

multiple source steps - one for each codebase

Builders’s build factory must include a source step for each codebase. Each of the source steps has a codebase attribute which is used to select an appropriate source stamp from the source stamp set for a build. This information comes from the arrived changes or from the scheduler’s configured default values.


Each source step has to have its own workdir set in order for the checkout to be done for each codebase in its own directory.


Ensure you specify the codebase within your source step’s Interpolate() calls (ex. http://.../svn/%(src:codebase:branch)s). See Interpolate for details.


Defining a codebaseGenerator that returns non-empty (not '') codebases will change the behavior of all the schedulers.

2.3.14. Multimaster


Buildbot Multimaster is considered experimental. There are still some companies using it in production. Don’t hesitate to use the mailing lists to share your experience.

Buildbot supports interconnection of several masters. This has to be done through a multi-master enabled message queue backend. As of now the only one supported is wamp and see wamp

There are then several strategy for introducing multimaster in your buildbot infra. A simple way to say it is by adding the concept of symmetrics and asymmetrics multimaster (like there is SMP and AMP for multi core CPUs)

Symmetric multimaster is when each master share the exact same configuration. They run the same builders, same schedulers, same everything, the only difference is that workers are connected evenly between the masters (by any means (e.g. DNS load balancing, etc)) Symmetric multimaster is good to use to scale buildbot horizontally.

Asymmetric multimaster is when each master have different configuration. Each master may have a specific responsibility (e.g schedulers, set of builder, UI). This was more how you did in 0.8, also because of its own technical limitations. A nice feature of asymmetric multimaster is that you can have the UI only handled by some masters.

Separating the UI from the controlling will greatly help in the performance of the UI, because badly written BuildSteps?? can stall the reactor for several seconds.

The fanciest configuration would probably be a symmetric configuration for everything but the UI. You would scale the number of UI master according to your number of UI users, and scale the number of engine masters to the number of workers.

Depending on your workload and size of master host, it is probably a good idea to start thinking of multimaster starting from a hundred workers connected.

Multimaster can also be used for high availability, and seamless upgrade of configuration code. Complex configuration indeed requires sometimes to restart the master to reload custom steps or code, or just to upgrade the upstream buildbot version.

In this case, you will implement following procedure:

  • Start new master(s) with new code and configuration.
  • Send a graceful shutdown to the old master(s).
  • New master(s) will start taking the new jobs, while old master(s) will just finish managing the running builds.
  • As an old master is finishing the running builds, it will drop the connections from the workers, who will then reconnect automatically, and by the mean of load balancer will get connected to a new master to run new jobs.

As buildbot nine has been designed to allow such procedure, it has not been implemented in production yet as we know. There is probably a new REST api needed in order to graceful shutdown a master, and the details of gracefully dropping the connection to the workers to be sorted out.

2.4. Secret Management

2.4.1. Requirements

Buildbot steps might need secrets to execute their actions. Secrets are used to execute commands or to create authenticated network connections. Secrets may be a SSH key, a password, or a file content like a wgetrc file or a public SSH key. To preserve confidentiality, the secrets values must not be printed or logged in the twisted or steps logs. Secrets must not be stored in the Buildbot configuration (master.cfg), as the source code is usually shared in SCM like git.

2.4.2. How to use Buildbot Secret Management Secrets and providers

Buildbot implements several providers for secrets retrieval:

  • File system based: secrets are written in a file. This is a simple solution for example when secrets are managed by config management system like Ansible Vault.
  • Third party backend based: secrets are stored by a specialized software. These solution are usually more secured.

Secrets providers are configured if needed in the master configuration. Multiple providers can be configured at once. The secret manager is a Buildbot service. The secret manager returns the specific provider results related to the providers registered in the configuration. How to use secrets in Buildbot

Secret can be used in Buildbot via the IRenderable mechanism. Two IRenderable actually implement secrets. Interpolate can be used if you need to mix secrets and other interpolation in the same argument. Interpolate can be used if your secret is directly used as a component argument.


Secret is a simple renderable which directly renders a secret.

As argument to steps

The following example shows a basic usage of secrets in Buildbot.

from buildbot.plugins import secrets, util
# First we declare that the secrets are stored in a directory of the filesystem
# each file contain one secret identified by the filename
c['secretsProviders'] = [secrets.SecretInAFile(dirname="/path/toSecretsFiles")]

# then in a buildfactory:

# use a secret on a shell command via Interpolate
f1.addStep(ShellCommand(util.Interpolate("wget -u user -p '%(secret:userpassword)s' '%(prop:urltofetch)s'")))
# .. or non shell form:
f1.addStep(ShellCommand(["wget", "-u", "user", "-p", util.Secret("userpassword"), util.Interpolate("%(prop:urltofetch)s")]))

Secrets are also interpolated in the build like properties are, and will be used in a command line for example.

As argument to services

You can use secrets to configure services. All services arguments are not compatible with secrets. See their individual documentation for details.

# First we declare that the secrets are stored in a directory of the filesystem
# each file contain one secret identified by the filename
c['secretsProviders'] = [secrets.SecretInAFile(dirname="/path/toSecretsFiles")]

# then for a reporter:
c['services'] = [GitHubStatusPush(token=util.Secret("githubToken"))] Secrets storages
c['secretsProviders'] = [secrets.SecretInAFile(dirname="/path/toSecretsFiles")]

In the passed directory, every file contains a secret identified by the filename.

e.g: a file user contains the text pa$$w0rd.


(required) Absolute path to directory containing the files with a secret.
(optional) if True (the default), trailing newlines are removed from the file contents.
c['secretsProviders'] = [secrets.SecretInVault(

Vault secures, stores, and tightly controls access to secrets. Vault presents a unified API to access multiple backends. To be authenticated in Vault, Buildbot need to send a token to the vault server. The token is generated when the Vault instance is initialized for the first time.

In the master configuration, the Vault provider is instantiated through the Buildbot service manager as a secret provider with the the Vault server address and the Vault token. The provider SecretInVault allows Buildbot to read secrets in Vault. For more information about Vault please visit: Vault: How to populate secrets in a build

To populate secrets in files during a build, 2 steps are used to create and delete the files on the worker. The files will be automatically deleted at the end of the build.

       f = BuildFactory()
       with f.withSecrets(secrets_list):
f = BuildFactory()
f.addSteps([list_of_step_definitions], withSecrets=[secrets_list])

In both cases the secrets_list is a list of tuple (secret path, secret value).

secrets_list = [('/first/path', Interpolate('write something and %(secret:somethingmore)s')),
                ('/second/path', Interpolate('%(secret:othersecret)s')]

The Interpolate class is used to render the value during the build execution. How to configure a Vault instance

Vault being a very generic system, it can be complex to install for the first time. Here is a simple tutorial to install the minimal Vault for use with Buildbot.

Use Docker to install Vault

A Docker image is available to help users installing Vault. Without any arguments, the command launches a Docker Vault developer instance, easy to use and test the functions. The developer version is already initialized and unsealed. To launch a Vault server please refer to the VaultDockerdocumentation:

In a shell:

docker run vault
Starting the vault instance

Once the Docker image is created, launch a shell terminal on the Docker image:

docker exec -i -t ``docker_vault_image_name`` /bin/sh

Then, export the environment variable VAULT_ADDR needed to init Vault.

export VAULT_ADDR='vault.server.adress'
Writing secrets

By default Vault is initialized with a mount named secret. To add a new secret:

vault write secret/new_secret_key value=new_secret_value

2.5. Configuration

The following sections describe the configuration of the various Buildbot components. The information available here is sufficient to create basic build and test configurations, and does not assume great familiarity with Python.

In more advanced Buildbot configurations, Buildbot acts as a framework for a continuous-integration application. The next section, Customization, describes this approach, with frequent references into the development documentation.

2.5.1. Configuring Buildbot

The buildbot’s behavior is defined by the config file, which normally lives in the master.cfg file in the buildmaster’s base directory (but this can be changed with an option to the buildbot create-mastercommand). This file completely specifies which Builders are to be run, which workers they should use, how Changes should be tracked, and where the status information is to be sent. The buildmaster’s buildbot.tac file names the base directory; everything else comes from the config file.

A sample config file was installed for you when you created the buildmaster, but you will need to edit it before your buildbot will do anything useful.

This chapter gives an overview of the format of this file and the various sections in it. You will need to read the later chapters to understand how to fill in each section properly. Config File Format

The config file is, fundamentally, just a piece of Python code which defines a dictionary named BuildmasterConfig, with a number of keys that are treated specially. You don’t need to know Python to do basic configuration, though, you can just copy the syntax of the sample file. If you are comfortable writing Python code, however, you can use all the power of a full programming language to achieve more complicated configurations.

The BuildmasterConfig name is the only one which matters: all other names defined during the execution of the file are discarded. When parsing the config file, the Buildmaster generally compares the old configuration with the new one and performs the minimum set of actions necessary to bring the buildbot up to date: Builders which are not changed are left untouched, and Builders which are modified get to keep their old event history.

The beginning of the master.cfg file typically starts with something like:

BuildmasterConfig = c = {}

Therefore a config key like change_source will usually appear in master.cfg as c['change_source'].

See Buildmaster Configuration Index for a full list of BuildMasterConfig keys.

Basic Python Syntax

The master configuration file is interpreted as Python, allowing the full flexibility of the language. For the configurations described in this section, a detailed knowledge of Python is not required, but the basic syntax is easily described.

Python comments start with a hash character #, tuples are defined with (parenthesis, pairs), and lists (arrays) are defined with [square, brackets]. Tuples and lists are mostly interchangeable. Dictionaries (data structures which map keys to values) are defined with curly braces: {'key1': value1, 'key2':value2}. Function calls (and object instantiation) can use named parameters, like steps.ShellCommand(command=["trial", "hello"]).

The config file starts with a series of import statements, which make various kinds of Steps and Statustargets available for later use. The main BuildmasterConfig dictionary is created, then it is populated with a variety of keys, described section-by-section in subsequent chapters. Predefined Config File Symbols

The following symbols are automatically available for use in the configuration file.


the base directory for the buildmaster. This string has not been expanded, so it may start with a tilde. It needs to be expanded before use. The config file is located in:

os.path.expanduser(os.path.join(basedir, 'master.cfg'))
the absolute path of the config file. The config file’s directory is located in os.path.dirname(__file__). Testing the Config File

To verify that the config file is well-formed and contains no deprecated or invalid elements, use the checkconfig command, passing it either a master directory or a config file.

% buildbot checkconfig master.cfg
Config file is good!
# or
% buildbot checkconfig /tmp/masterdir
Config file is good!

If the config file has deprecated features (perhaps because you’ve upgraded the buildmaster and need to update the config file to match), they will be announced by checkconfig. In this case, the config file will work, but you should really remove the deprecated items and use the recommended replacements instead:

% buildbot checkconfig master.cfg
/usr/lib/python2.4/site-packages/buildbot/ DeprecationWarning: c['sources'] is
deprecated as of 0.7.6 and will be removed by 0.8.0 . Please use c['change_source'] instead.
Config file is good!

If you have errors in your configuration file, checkconfig will let you know:

% buildbot checkconfig master.cfg
Configuration Errors:
c['workers'] must be a list of Worker instances
no workers are configured
builder 'smoketest' uses unknown workers 'linux-002'

If the config file is simply broken, that will be caught too:

% buildbot checkconfig master.cfg
error while parsing config file:
Traceback (most recent call last):
File "/home/buildbot/master/bin/buildbot", line 4, in <module>
File "/home/buildbot/master/buildbot/scripts/", line 1358, in run
    if not doCheckConfig(so):
File "/home/buildbot/master/buildbot/scripts/", line 1079, in doCheckConfig
    return cl.load(quiet=quiet)
File "/home/buildbot/master/buildbot/scripts/", line 29, in load
    self.basedir, self.configFileName)
--- <exception caught here> ---
File "/home/buildbot/master/buildbot/", line 147, in loadConfig
    exec f in localDict
exceptions.SyntaxError: invalid syntax (master.cfg, line 52)
Configuration Errors:
error while parsing config file: invalid syntax (master.cfg, line 52) (traceback in logfile) Loading the Config File

The config file is only read at specific points in time. It is first read when the buildmaster is launched.


If the configuration is invalid, the master will display the errors in the console output, but will not exit.

Reloading the Config File (reconfig)

If you are on the system hosting the buildmaster, you can send a SIGHUP signal to it: the buildbot tool has a shortcut for this:

buildbot reconfig BASEDIR

This command will show you all of the lines from twistd.log that relate to the reconfiguration. If there are any problems during the config-file reload, they will be displayed in these lines.

When reloading the config file, the buildmaster will endeavor to change as little as possible about the running system. For example, although old status targets may be shut down and new ones started up, any status targets that were not changed since the last time the config file was read will be left running and untouched. Likewise any Builders which have not been changed will be left running. If a Builder is modified (say, the build process is changed) while a Build is currently running, that Buildwill keep running with the old process until it completes. Any previously queued Builds (or Builds which get queued after the reconfig) will use the new process.


Buildbot’s reconfiguration system is fragile for a few difficult-to-fix reasons:

  • Any modules imported by the configuration file are not automatically reloaded. Python modules such as may help here, but reloading modules is fraught with subtleties and difficult-to-decipher failure cases.
  • During the reconfiguration, active internal objects are divorced from the service hierarchy, leading to tracebacks in the web interface and other components. These are ordinarily transient, but with HTTP connection caching (either by the browser or an intervening proxy) they can last for a long time.
  • If the new configuration file is invalid, it is possible for Buildbot’s internal state to be corrupted, leading to undefined results. When this occurs, it is best to restart the master.
  • For more advanced configurations, it is impossible for Buildbot to tell if the configuration for a Builder or Scheduler has changed, and thus the Builder or Scheduler will always be reloaded. This occurs most commonly when a callable is passed as a configuration parameter.

The bbproto project (at may help to construct large (multi-file) configurations which can be effectively reloaded and reconfigured.

2.5.2. Global Configuration

The keys in this section affect the operations of the buildmaster globally. Database Specification

Buildbot requires a connection to a database to maintain certain state information, such as tracking pending build requests. In the default configuration Buildbot uses a file-based SQLite database, stored in the state.sqlite file of the master’s base directory. Override this configuration with the db_url parameter.

Buildbot accepts a database configuration in a dictionary named db. All keys are optional:

c['db'] = {
    'db_url' : 'sqlite:///state.sqlite',

The db_url key indicates the database engine to use. The format of this parameter is completely documented at, but is generally of the form:


These parameters can be specified directly in the configuration dictionary, as c['db_url'] and c['db_poll_interval'], although this method is deprecated.

The following sections give additional information for particular database backends:


For sqlite databases, since there is no host and port, relative paths are specified with sqlite:/// and absolute paths with sqlite:////. Examples:

c['db_url'] = "sqlite:///state.sqlite"

SQLite requires no special configuration.

c['db_url'] = "mysql://"

The max_idle argument for MySQL connections is unique to Buildbot, and should be set to something less than the wait_timeout configured for your server. This controls the SQLAlchemy pool_recycleparameter, which defaults to no timeout. Setting this parameter ensures that connections are closed and re-opened after the configured amount of idle time. If you see errors such as _mysql_exceptions.OperationalError: (2006, 'MySQL server has gone away'), this means your max_idlesetting is probably too high. show global variables like 'wait_timeout'; will show what the currently configured wait_timeout is on your MySQL server.

Buildbot requires use_unique=True and charset=utf8, and will add them automatically, so they do not need to be specified in db_url.

MySQL defaults to the MyISAM storage engine, but this can be overridden with the storage_engineURL argument.

c['db_url'] = "postgresql://username:password@hostname/dbname"

PosgreSQL requires no special configuration. MQ Specification

Buildbot uses a message-queueing system to handle communication within the master. Messages are used to indicate events within the master, and components that are interested in those events arrange to receive them.

The message queueing implementation is configured as a dictionary in the mq option. The type key describes the type of MQ implementation to be used. Note that the implementation type cannot be changed in a reconfig.

The available implementation types are described in the following sections.

c['mq'] = {
    'type' : 'simple',
    'debug' : False,

This is the default MQ implementation. Similar to SQLite, it has no additional software dependencies, but does not support multi-master mode.

Note that this implementation also does not support message persistence across a restart of the master. For example, if a change is received, but the master shuts down before the schedulers can create build requests for it, then those schedulers will not be notified of the change when the master starts again.

The debug key, which defaults to False, can be used to enable logging of every message produced on this master.



At the moment, wamp is the only message queue implementation for multimaster. It has been privileged as this is the only message queue that have very solid support for Twisted. Other more common message queue systems like RabbitMQ (using the AMQP protocol) do not have convincing driver for twisted, and this would require to run on threads, which will add an important performance overhead.

c['mq'] = {
    'type' : 'wamp',
    'router_url': 'ws://localhost:8080/ws',
    'realm': 'realm1',
    'wamp_debug_level' : 'error' # valid are: none, critical, error, warn, info, debug, trace

This is a MQ implementation using wamp protocol. This implementation uses Python Autobahnwamp client library, and is fully asynchronous (no use of threads). To use this implementation, you need a wamp router like Crossbar.

Please refer to Crossbar documentation for more details, but the default Crossbar setup will just work with Buildbot, provided you use the example mq configuration above, and start Crossbar with:

# of course, you should work in a virtualenv...
pip install crossbar
crossbar init
crossbar start

The implementation does not yet support wamp authentication. This MQ allows buildbot to run in multi-master mode.

Note that this implementation also does not support message persistence across a restart of the master. For example, if a change is received, but the master shuts down before the schedulers can create build requests for it, then those schedulers will not be notified of the change when the master starts again.

router_url (mandatory): points to your router websocket url.
Buildbot is only supporting wamp over websocket, which is a sub-protocol of http. SSL is supported using wss:// instead of ws://.

realm (optional, defaults to buildbot): defines the wamp realm to use for your buildbot messages.

wamp_debug_level (optional, defaults to error): defines the log level of autobahn.

You must use a router with very reliable connection to the master. If for some reason, the wamp connection is lost, then the master will stop, and should be restarted via a process manager. Multi-master mode

See Multimaster for details on the Multi-master mode in Buildbot Nine.

By default, Buildbot makes coherency checks that prevents typo in your master.cfg It make sure schedulers are not referencing unknown builders, and enforces there is at least one builder.

In the case of a asymmetric multimaster, those coherency checks can be harmful and prevent you to implement what you want. For example you might want to have one master dedicated to the UI, so that a big load generated by builds will not impact page load times.

To enable multi-master mode in this configuration, you will need to set the multiMaster option so that buildbot doesn’t warn about missing schedulers or builders.

# Enable multiMaster mode; disables warnings about unknown builders and
# schedulers
c['multiMaster'] = True
c['db'] = {
    'db_url' : 'mysql://...',
c['mq'] = {  # Need to enable multimaster aware mq. Wamp is the only option for now.
    'type' : 'wamp',
    'router_url': 'ws://localhost:8080',
    'realm': 'realm1',
    'wamp_debug_level' : 'error' # valid are: none, critical, error, warn, info, debug, trace
} Site Definitions

Three basic settings describe the buildmaster in status reports:

c['title'] = "Buildbot"
c['titleURL'] = ""

title is a short string that will appear at the top of this buildbot installation’s home page (linked to the titleURL).

titleURL is a URL string that must end with a slash (/). HTML status displays will show title as a link to titleURL. This URL is often used to provide a link from buildbot HTML pages to your project’s home page.

The buildbotURL string should point to the location where the buildbot’s internal web server is visible. This URL must end with a slash (/).

When status notices are sent to users (e.g., by email or over IRC), buildbotURL will be used to create a URL to the specific build or problem that they are being notified about. Log Handling
c['logCompressionMethod'] = 'gz'
c['logMaxSize'] = 1024*1024 # 1M
c['logMaxTailSize'] = 32768
c['logEncoding'] = 'utf-8'

The logCompressionLimit enables compression of build logs on disk for logs that are bigger than the given size, or disables that completely if set to False. The default value is 4096, which should be a reasonable default on most file systems. This setting has no impact on status plugins, and merely affects the required disk space on the master for build logs.

The logCompressionMethod controls what type of compression is used for build logs. The default is ‘gz’, and the other valid option are ‘raw’ (no compression), ‘gz’ or ‘lz4’ (required lz4 package).

Please find below some stats extracted from 50x “trial Pyflakes” runs (results may differ according to log type).

Space saving details
compression raw log size compressed log size space saving compression speed
bz2 2.981 MB 0.603 MB 79.77% 3.433 MB/s
gz 2.981 MB 0.568 MB 80.95% 6.604 MB/s
lz4 2.981 MB 0.844 MB 71.68% 77.668 MB/s

The logMaxSize parameter sets an upper limit (in bytes) to how large logs from an individual build step can be. The default value is None, meaning no upper limit to the log size. Any output exceeding logMaxSize will be truncated, and a message to this effect will be added to the log’s HEADER channel.

If logMaxSize is set, and the output from a step exceeds the maximum, the logMaxTailSize parameter controls how much of the end of the build log will be kept. The effect of setting this parameter is that the log will contain the first logMaxSize bytes and the last logMaxTailSize bytes of output. Don’t set this value too high, as the the tail of the log is kept in memory.

The logEncoding parameter specifies the character encoding to use to decode bytestrings provided as logs. It defaults to utf-8, which should work in most cases, but can be overridden if necessary. In extreme cases, a callable can be specified for this parameter. It will be called with byte strings, and should return the corresponding Unicode string.

This setting can be overridden for a single build step with the logEncoding step parameter. It can also be overridden for a single log file by passing the logEncoding parameter to addLog. Data Lifetime

Previously Buildbot implemented a global configuration for horizons. Now it is implemented as an utility Builder, and shall be configured via JanitorConfigurator

c['caches'] = {
    'Changes' : 100,     # formerly c['changeCacheSize']
    'Builds' : 500,      # formerly c['buildCacheSize']
    'chdicts' : 100,
    'BuildRequests' : 10,
    'SourceStamps' : 20,
    'ssdicts' : 20,
    'objectids' : 10,
    'usdicts' : 100,

The caches configuration key contains the configuration for Buildbot’s in-memory caches. These caches keep frequently-used objects in memory to avoid unnecessary trips to the database. Caches are divided by object type, and each has a configurable maximum size.

The default size for each cache is 1, except where noted below. A value of 1 allows Buildbot to make a number of optimizations without consuming much memory. Larger, busier installations will likely want to increase these values.

The available caches are:


the number of change objects to cache in memory. This should be larger than the number of changes that typically arrive in the span of a few minutes, otherwise your schedulers will be reloading changes from the database every time they run. For distributed version control systems, like Git or Hg, several thousand changes may arrive at once, so setting this parameter to something like 10000 isn’t unreasonable.

This parameter is the same as the deprecated global parameter changeCacheSize. Its default value is 10.


The buildCacheSize parameter gives the number of builds for each builder which are cached in memory. This number should be larger than the number of builds required for commonly-used status displays (the waterfall or grid views), so that those displays do not miss the cache on a refresh.

This parameter is the same as the deprecated global parameter buildCacheSize. Its default value is 15.

The number of rows from the changes table to cache in memory. This value should be similar to the value for Changes.
The number of BuildRequest objects kept in memory. This number should be higher than the typical number of outstanding build requests. If the master ordinarily finds jobs for BuildRequests immediately, you may set a lower value.
the number of SourceStamp objects kept in memory. This number should generally be similar to the number BuildRequesets.
The number of rows from the sourcestamps table to cache in memory. This value should be similar to the value for SourceStamps.
The number of object IDs - a means to correlate an object in the Buildbot configuration with an identity in the database–to cache. In this version, object IDs are not looked up often during runtime, so a relatively low value such as 10 is fine.

The number of rows from the users table to cache in memory. Note that for a given user there will be a row for each attribute that user has.

c[‘buildCacheSize’] = 15 Merging Build Requests
c['collapseRequests'] = True

This is a global default value for builders’ collapseRequests parameter, and controls the merging of build requests.

This parameter can be overridden on a per-builder basis. See Collapsing Build Requests for the allowed values for this parameter. Prioritizing Builders
def prioritizeBuilders(buildmaster, builders):
c['prioritizeBuilders'] = prioritizeBuilders

By default, buildbot will attempt to start builds on builders in order, beginning with the builder with the oldest pending request. Customize this behavior with the prioritizeBuilders configuration key, which takes a callable. See Builder Priority Functions for details on this callable.

This parameter controls the order that the build master can start builds, and is useful in situations where there is resource contention between builders, e.g., for a test database. It does not affect the order in which a builder processes the build requests in its queue. For that purpose, see Prioritizing Builds. Setting the PB Port for Workers
c['protocols'] = {"pb": {"port": 10000}}

The buildmaster will listen on a TCP port of your choosing for connections from workers. It can also use this port for connections from remote Change Sources, status clients, and debug tools. This port should be visible to the outside world, and you’ll need to tell your worker admins about your choice.

It does not matter which port you pick, as long it is externally visible; however, you should probably use something larger than 1024, since most operating systems don’t allow non-root processes to bind to low-numbered ports. If your buildmaster is behind a firewall or a NAT box of some sort, you may have to configure your firewall to permit inbound connections to this port.

c['protocols']['pb']['port'] is a strports specification string, defined in the twisted.application.strports module (try pydoc twisted.application.strports to get documentation on the format).

This means that you can have the buildmaster listen on a localhost-only port by doing:

c['protocols'] = {"pb": {"port": "tcp:10000:interface="}}

This might be useful if you only run workers on the same machine, and they are all configured to contact the buildmaster at localhost:10000.


In Buildbot versions <=0.8.8 you might see slavePortnum option. This option contains same value as c['protocols']['pb']['port'] but not recommended to use. Defining Global Properties

The properties configuration key defines a dictionary of properties that will be available to all builds started by the buildmaster:

c['properties'] = {
    'Widget-version' : '1.2',
    'release-stage' : 'alpha'
} Manhole

If you set manhole to an instance of one of the classes in buildbot.manhole, you can telnet or ssh into the buildmaster and get an interactive Python shell, which may be useful for debugging buildbot internals. It is probably only useful for buildbot developers. It exposes full access to the buildmaster’s account (including the ability to modify and delete files), so it should not be enabled with a weak or easily guessable password.

There are three separate Manhole classes. Two of them use SSH, one uses unencrypted telnet. Two of them use a username+password combination to grant access, one of them uses an SSH-style authorized_keys file which contains a list of ssh public keys.


Using any Manhole requires that cryptography and pyasn1 be installed. These are not part of the normal Buildbot dependencies.

You construct this with the name of a file that contains one SSH public key per line, just like ~/.ssh/authorized_keys. If you provide a non-absolute filename, it will be interpreted relative to the buildmaster’s base directory. You must also specify a directory which contains an SSH host key for the Manhole server.
This one accepts SSH connections but asks for a username and password when authenticating. It accepts only one such pair. You must also specify a directory which contains an SSH host key for the Manhole server.
This accepts regular unencrypted telnet connections, and asks for a username/password pair before providing access. Because this username/password is transmitted in the clear, and because Manhole access to the buildmaster is equivalent to granting full shell privileges to both the buildmaster and all the workers (and to all accounts which then run code produced by the workers), it is highly recommended that you use one of the SSH manholes instead.
# some examples:
from buildbot.plugins import util
c['manhole'] = util.AuthorizedKeysManhole(1234, "authorized_keys", ssh_hostkey_dir="/data/ssh_host_keys/")
c['manhole'] = util.PasswordManhole(1234, "alice", "mysecretpassword", ssh_hostkey_dir="/data/ssh_host_keys/")
c['manhole'] = util.TelnetManhole(1234, "bob", "snoop_my_password_please")

The Manhole instance can be configured to listen on a specific port. You may wish to have this listening port bind to the loopback interface (sometimes known as lo0localhost, or to restrict access to clients which are running on the same host.

from buildbot.plugins import util
c['manhole'] = util.PasswordManhole("tcp:9999:interface=","admin","passwd", ssh_hostkey_dir="/data/ssh_host_keys/")

To have the Manhole listen on all interfaces, use "tcp:9999" or simply 9999. This port specification uses twisted.application.strports, so you can make it listen on SSL or even UNIX-domain sockets if you want.

Note that using any Manhole requires that the TwistedConch package be installed.

The buildmaster’s SSH server will use a different host key than the normal sshd running on a typical unix host. This will cause the ssh client to complain about a host key mismatch, because it does not realize there are two separate servers running on the same host. To avoid this, use a clause like the following in your .ssh/config file:

Host remotehost-buildbot
HostName remotehost
HostKeyAlias remotehost-buildbot
Port 9999
# use 'user' if you use PasswordManhole and your name is not 'admin'.
# if you use AuthorizedKeysManhole, this probably doesn't matter.
User admin
Using Manhole

After you have connected to a manhole instance, you will find yourself at a Python prompt. You have access to two objects: master (the BuildMaster) and status (the master’s Status object). Most interesting objects on the master can be reached from these two objects.

To aid in navigation, the show method is defined. It displays the non-method attributes of an object.

A manhole session might look like:

>>> show(master)
data attributes of <buildbot.master.BuildMaster instance at 0x7f7a4ab7df38>
                       basedir : '/home/dustin/code/buildbot/t/buildbot/'...
                     botmaster : <type 'instance'>
                buildCacheSize : None
                  buildHorizon : None
                   buildbotURL : http://localhost:8010/
               changeCacheSize : None
                    change_svc : <type 'instance'>
                configFileName : master.cfg
                            db : <class 'buildbot.db.connector.DBConnector'>
                        db_url : sqlite:///state.sqlite
>>> show(['win32'])
data attributes of <Builder ''builder'' at 48963528>
>>> win32 = _
>>> win32.category = 'w32' Metrics Options
c['metrics'] = dict(log_interval=10, periodic_interval=10)

metrics can be a dictionary that configures various aspects of the metrics subsystem. If metrics is None, then metrics collection, logging and reporting will be disabled.

log_interval determines how often metrics should be logged to twistd.log. It defaults to 60s. If set to 0 or None, then logging of metrics will be disabled. This value can be changed via a reconfig.

periodic_interval determines how often various non-event based metrics are collected, such as memory usage, uncollectable garbage, reactor delay. This defaults to 10s. If set to 0 or None, then periodic collection of this data is disabled. This value can also be changed via a reconfig.

Read more about metrics in the Metrics section in the developer documentation. Statistics Service

The Statistics Service (stats service for short) supports for collecting arbitrary data from within a running Buildbot instance and export it do a number of storage backends. Currently, only InfluxDB is supported as a storage backend. Also, InfluxDB (or any other storage backend) is not a mandatory dependency. Buildbot can run without it although StatsService will be of no use in such a case. At present, StatsService can keep track of build properties, build times (start, end, duration) and arbitrary data produced inside Buildbot (more on this later).

Example usage:

captures = [stats.CaptureProperty('Builder1', 'tree-size-KiB'),
c['services'] = []
        stats.InfluxStorageService('localhost', 8086, 'root', 'root', 'test', captures)
    ], name="StatsService"))

The services configuration value should be initialized as a list and a StatsService instance should be appended to it as shown in the example above.

Statistics Service
class buildbot.statistics.stats_service.StatsService

This is the main class for statistics service. It is initialized in the master configuration as show in the example above. It takes two arguments:

A list of storage backends (see Storage Backends). In the example above, stats.InfluxStorageService is an instance of a storage backend. Each storage backend is an instances of subclasses of statsStorageBase.
The name of this service.

yieldMetricsValue: This method can be used to send arbitrary data for storage. (See Using StatsService.yieldMetricsValue for more information.)

Capture Classes
class buildbot.statistics.capture.CaptureProperty

Instance of this class declares which properties must be captured and sent to the Storage Backends. It takes the following arguments:

The name of builder in which the property is recorded.
The name of property needed to be recorded as a statistic.
(Optional) A custom callback function for this class. This callback function should take in two arguments - build_properties (dict) and property_name (str) and return a string that will be sent for storage in the storage backends.
If this is set to True, then the property name can be a regular expression. All properties matching this regular expression will be sent for storage.
class buildbot.statistics.capture.CapturePropertyAllBuilders

Instance of this class declares which properties must be captured on all builders and sent to the Storage Backends. It takes the following arguments:

The name of property needed to be recorded as a statistic.
(Optional) A custom callback function for this class. This callback function should take in two arguments - build_properties (dict) and property_name (str) and return a string that will be sent for storage in the storage backends.
If this is set to True, then the property name can be a regular expression. All properties matching this regular expression will be sent for storage.
class buildbot.statistics.capture.CaptureBuildStartTime

Instance of this class declares which builders’ start times are to be captured and sent to Storage Backends. It takes the following arguments:

The name of builder whose times are to be recorded.
(Optional) A custom callback function for this class. This callback function should take in a Python datetime object and return a string that will be sent for storage in the storage backends.
class buildbot.statistics.capture.CaptureBuildStartTimeAllBuilders

Instance of this class declares start times of all builders to be captured and sent to Storage Backends. It takes the following arguments:

(Optional) A custom callback function for this class. This callback function should take in a Python datetime object and return a string that will be sent for storage in the storage backends.
class buildbot.statistics.capture.CaptureBuildEndTime

Exactly like CaptureBuildStartTime except it declares the builders whose end time is to be recorded. The arguments are same as CaptureBuildStartTime.

class buildbot.statistics.capture.CaptureBuildEndTimeAllBuilders

Exactly like CaptureBuildStartTimeAllBuilders except it declares all builders’ end time to be recorded. The arguments are same as CaptureBuildStartTimeAllBuilders.

class buildbot.statistics.capture.CaptureBuildDuration

Instance of this class declares the builders whose build durations are to be recorded. It takes the following arguments:

The name of builder whose times are to be recorded.
Can be one of three: 'seconds''minutes', or 'hours'. This is the units in which the build time will be reported.
(Optional) A custom callback function for this class. This callback function should take in two Python datetime objects - a start_time and an end_time and return a string that will be sent for storage in the storage backends.
class buildbot.statistics.capture.CaptureBuildDurationAllBuilders

Instance of this class declares build durations to be recorded for all builders. It takes the following arguments:

Can be one of three: 'seconds''minutes', or 'hours'. This is the units in which the build time will be reported.
(Optional) A custom callback function for this class. This callback function should take in two Python datetime objects - a start_time and an end_time and return a string that will be sent for storage in the storage backends.
class buildbot.statistics.capture.CaptureData

Instance of this capture class is for capturing arbitrary data that is not stored as build-data. Needs to be used in conjunction with yieldMetricsValue (See Using StatsService.yieldMetricsValue). Takes the following arguments:

The name of data to be captured. Same as in yieldMetricsValue.
The name of builder whose times are to be recorded.
The callback function for this class. This callback receives the data sent to yieldMetricsValueas post_data (See Using StatsService.yieldMetricsValue). It must return a string that is to be sent to the storage backends for storage.
class buildbot.statistics.capture.CaptureDataAllBuilders

Instance of this capture class for capturing arbitrary data that is not stored as build-data on all builders. Needs to be used in conjunction with yieldMetricsValue (See Using StatsService.yieldMetricsValue). Takes the following arguments:

The name of data to be captured. Same as in yieldMetricsValue.
The callback function for this class. This callback receives the data sent to yieldMetricsValueas post_data (See Using StatsService.yieldMetricsValue). It must return a string that is to be sent to the storage backends for storage.
Using StatsService.yieldMetricsValue

Advanced users can modify BuildSteps to use StatsService.yieldMetricsValue which will send arbitrary data for storage to the StatsService. It takes the following arguments:

The name of the data being sent or storage.
A dictionary of key value pair that is sent for storage. The keys will act as columns in a database and the value is stored under that column.
The integer build id of the current build. Obtainable in all BuildSteps.

Along with using yieldMetricsValue, the user will also need to use the CaptureData capture class. As an example, we can add the following to a build step:

yieldMetricsValue('test_data_name', {'some_data': 'some_value'}, buildid)

Then, we can add in the master configuration a capture class like this:

captures = [CaptureBuildData('test_data_name', 'Builder1')]

Pass this captures list to a storage backend (as shown in the example at the top of this section) for capturing this data.

Storage Backends

Storage backends are responsible for storing any statistics data sent to them. A storage backend will generally be some sort of a database-server running on a machine. (Note: This machine may be different from the one running BuildMaster)

Currently, only InfluxDB is supported as a storage backend.

class buildbot.statistics.storage_backends.influxdb_client.InfluxStorageService

This class is a Buildbot client to the InfluxDB storage backend. InfluxDB is a distributed, time series database that employs a key-value pair storage system.

It requires the following arguments:

The URL where the service is running.
The port on which the service is listening.
Username of a InfluxDB user.
Password for user.
The name of database to be used.
A list of objects of Capture Classes. This tells which statistics are to be stored in this storage backend.
(Optional) The name of this storage backend. secretsProviders

see Secret Management for details on secret concepts.

Example usage:

c['secretsProviders'] = [ .. ]

secretsProviders is a list of secrets storage. See Secret Management to configure an available secret storage provider. BuildbotNetUsageData

Since buildbot 0.9.0, buildbot has a simple feature which sends usage analysis info to This is very important for buildbot developers to understand how the community is using the tools. This allows to better prioritize issues, and understand what plugins are actually being used. This will also be a tool to decide whether to keep support for very old tools. For example buildbot contains support for the venerable CVS, but we have no information whether it actually works beyond the unit tests. We rely on the community to test and report issues with the old features.

With BuildbotNetUsageData, we can know exactly what combination of plugins are working together, how much people are customizing plugins, what versions of the main dependencies people run.

We take your privacy very seriously.

BuildbotNetUsageData will never send information specific to your Code or Intellectual Property. No repository url, shell command values, host names, ip address or custom class names. If it does, then this is a bug, please report.

We still need to track unique number for installation. This is done via doing a sha1 hash of master’s hostname, installation path and fqdn. Using a secure hash means there is no way of knowing hostname, path and fqdn given the hash, but still there is a different hash for each master.

You can see exactly what is sent in the master’s twisted.log. Usage data is sent every time the master is started.

BuildbotNetUsageData can be configured with 4 values:

  • c['buildbotNetUsageData'] = None disables the feature

  • c['buildbotNetUsageData'] = 'basic' sends the basic information to buildbot including:

    • versions of buildbot, python and twisted
    • platform information (CPU, OS, distribution, python flavor (i.e CPython vs PyPy))
    • mq and database type (mysql or sqlite?)
    • www plugins usage
    • Plugins usages: This counts the number of time each class of buildbot is used in your configuration. This counts workers, builders, steps, schedulers, change sources. If the plugin is subclassed, then it will be prefixed with a >

    example of basic report (for the metabuildbot):

    'versions': {
        'Python': '2.7.6',
        'Twisted': '15.5.0',
        'Buildbot': '0.9.0rc2-176-g5fa9dbf'
    'platform': {
        'machine': 'x86_64',
        'python_implementation': 'CPython',
        'version': '#140-Ubuntu SMP Mon Jul',
        'distro:': ('Ubuntu', '14.04', 'trusty')
    'db': 'sqlite',
    'mq': 'simple',
    'plugins': {
        'buildbot.schedulers.forcesched.ForceScheduler': 2,
        'buildbot.schedulers.triggerable.Triggerable': 1,
        'buildbot.config.BuilderConfig': 4,
        'buildbot.schedulers.basic.AnyBranchScheduler': 2,
        'buildbot.steps.source.git.Git': 4,
        '>>buildbot.steps.trigger.Trigger': 2,
        '>>>buildbot.worker.base.Worker': 4,
        'buildbot.reporters.irc.IRC': 1,
        '>>>buildbot.process.buildstep.LoggingBuildStep': 2},
    'www_plugins': ['buildbot_travis', 'waterfall_view']
  • c['buildbotNetUsageData'] = 'full' sends the basic information plus additional information:

    • configuration of each builders: how the steps are arranged together. for ex:
        'builders': [
            ['buildbot.steps.source.git.Git', '>>>buildbot.process.buildstep.LoggingBuildStep'],
            ['buildbot.steps.source.git.Git', '>>buildbot.steps.trigger.Trigger'],
            ['buildbot.steps.source.git.Git', '>>>buildbot.process.buildstep.LoggingBuildStep'],
            ['buildbot.steps.source.git.Git', '>>buildbot.steps.trigger.Trigger']]
  • c['buildbotNetUsageData'] = myCustomFunction. You can also specify exactly what to send using a callback.

    The custom function will take the generated data from full report in the form of a dictionary, and return a customized report as a jsonable dictionary. You can use this to filter any information you don’t want to disclose. You can use a custom http_proxy environment variable in order to not send any data while developing your callback. Users Options
from buildbot.plugins import util
c['user_managers'] = []

user_managers contains a list of ways to manually manage User Objects within Buildbot (see User Objects). Currently implemented is a commandline tool buildbot user, described at length in user. In the future, a web client will also be able to manage User Objects and their attributes.

As shown above, to enable the buildbot user tool, you must initialize a CommandlineUserManagerinstance in your master.cfgCommandlineUserManager instances require the following arguments:

This is the username that will be registered on the PB connection and need to be used when calling buildbot user.
This is the passwd that will be registered on the PB connection and need to be used when calling buildbot user.
The PB connection port must be different than c[‘protocols’][‘pb’][‘port’] and be specified when calling buildbot user Input Validation
import re
c['validation'] = {
    'branch' : re.compile(r'^[\w.+/~-]*$'),
    'revision' : re.compile(r'^[ \w\.\-\/]*$'),
    'property_name' : re.compile(r'^[\w\.\-\/\~:]*$'),
    'property_value' : re.compile(r'^[\w\.\-\/\~:]*$'),

This option configures the validation applied to user inputs of various types. This validation is important since these values are often included in command-line arguments executed on workers. Allowing arbitrary input from untrusted users may raise security concerns.

The keys describe the type of input validated; the values are compiled regular expressions against which the input will be matched. The defaults for each type of input are those given in the example, above. Revision Links

The revlink parameter is used to create links from revision IDs in the web status to a web-view of your source control system. The parameter’s value must be a callable.

By default, Buildbot is configured to generate revlinks for a number of open source hosting platforms.

The callable takes the revision id and repository argument, and should return an URL to the revision. Note that the revision id may not always be in the form you expect, so code defensively. In particular, a revision of “??” may be supplied when no other information is available.

Note that SourceStamps that are not created from version-control changes (e.g., those created by a Nightly or Periodic scheduler) may have an empty repository string, if the repository is not known to the scheduler.

Revision Link Helpers

Buildbot provides two helpers for generating revision links. buildbot.revlinks.RevlinkMatcher takes a list of regular expressions, and replacement text. The regular expressions should all have the same number of capture groups. The replacement text should have sed-style references to that capture groups (i.e. ‘1’ for the first capture group), and a single ‘%s’ reference, for the revision ID. The repository given is tried against each regular expression in turn. The results are the substituted into the replacement text, along with the revision ID to obtain the revision link.

from buildbot.plugins import util
c['revlink'] = util.RevlinkMatch([r'git://*)'],

buildbot.revlinks.RevlinkMultiplexer takes a list of revision link callables, and tries each in turn, returning the first successful match. Codebase Generator
all_repositories = {
    r'https://hg/hg/mailsuite/mailclient': 'mailexe',
    r'https://hg/hg/mailsuite/mapilib': 'mapilib',
    r'https://hg/hg/mailsuite/imaplib': 'imaplib',
    r'': 'mailexe',
    r'': 'mapilib',
    r'': 'imaplib',

def codebaseGenerator(chdict):
    return all_repositories[chdict['repository']]

c['codebaseGenerator'] = codebaseGenerator

For any incoming change, the codebase is set to ‘’. This codebase value is sufficient if all changes come from the same repository (or clones). If changes come from different repositories, extra processing will be needed to determine the codebase for the incoming change. This codebase will then be a logical name for the combination of repository and or branch etc.

The codebaseGenerator accepts a change dictionary as produced by the buildbot.db.changes.ChangesConnectorComponent, with a changeid equal to None.

2.5.3. Change Sources and Changes

change source is the mechanism which is used by Buildbot to get information about new changes in a repository maintained by a Version Control System.

These change sources fall broadly into two categories: pollers which periodically check the repository for updates; and hooks, where the repository is configured to notify Buildbot whenever an update occurs.

Change is an abstract way that Buildbot uses to represent changes in any of the Version Control Systems it supports. It contains just enough information needed to acquire specific version of the tree when needed. This usually happens as one of the first steps in a Build.

This concept does not map perfectly to every version control system. For example, for CVS Buildbot must guess that version updates made to multiple files within a short time represent a single change.

Changes can be provided by a variety of ChangeSource types, although any given project will typically have only a single ChangeSource active. How Different VC Systems Specify Sources

For CVS, the static specifications are repository and module. In addition to those, each build uses a timestamp (or omits the timestamp to mean the latest) and branch tag (which defaults to HEAD). These parameters collectively specify a set of sources from which a build may be performed.

Subversion, combines the repository, module, and branch into a single Subversion URL parameter. Within that scope, source checkouts can be specified by a numeric revision number (a repository-wide monotonically-increasing marker, such that each transaction that changes the repository is indexed by a different revision number), or a revision timestamp. When branches are used, the repository and module form a static baseURL, while each build has a revision number and a branch (which defaults to a statically-specified defaultBranch). The baseURL and branch are simply concatenated together to derive the repourl to use for the checkout.

Perforce is similar. The server is specified through a P4PORT parameter. Module and branch are specified in a single depot path, and revisions are depot-wide. When branches are used, the p4baseand defaultBranch are concatenated together to produce the depot path.

Bzr (which is a descendant of Arch/Bazaar, and is frequently referred to as “Bazaar”) has the same sort of repository-vs-workspace model as Arch, but the repository data can either be stored inside the working directory or kept elsewhere (either on the same machine or on an entirely different machine). For the purposes of Buildbot (which never commits changes), the repository is specified with a URL and a revision number.

The most common way to obtain read-only access to a bzr tree is via HTTP, simply by making the repository visible through a web server like Apache. Bzr can also use FTP and SFTP servers, if the worker process has sufficient privileges to access them. Higher performance can be obtained by running a special Bazaar-specific server. None of these matter to the buildbot: the repository URL just has to match the kind of server being used. The repoURL argument provides the location of the repository.

Branches are expressed as subdirectories of the main central repository, which means that if branches are being used, the BZR step is given a baseURL and defaultBranch instead of getting the repoURL argument.

Darcs doesn’t really have the notion of a single master repository. Nor does it really have branches. In Darcs, each working directory is also a repository, and there are operations to push and pull patches from one of these repositories to another. For the Buildbot’s purposes, all you need to do is specify the URL of a repository that you want to build from. The worker will then pull the latest patches from that repository and build them. Multiple branches are implemented by using multiple repositories (possibly living on the same server).

Builders which use Darcs therefore have a static repourl which specifies the location of the repository. If branches are being used, the source Step is instead configured with a baseURL and a defaultBranch, and the two strings are simply concatenated together to obtain the repository’s URL. Each build then has a specific branch which replaces defaultBranch, or just uses the default one. Instead of a revision number, each build can have a context, which is a string that records all the patches that are present in a given tree (this is the output of darcs changes --context, and is considerably less concise than, e.g. Subversion’s revision number, but the patch-reordering flexibility of Darcs makes it impossible to provide a shorter useful specification).

Mercurial follows a decentralized model, and each repository can have several branches and tags. The source Step is configured with a static repourl which specifies the location of the repository. Branches are configured with the defaultBranch argument. The revision is the hash identifier returned by hg identify.

Git also follows a decentralized model, and each repository can have several branches and tags. The source Step is configured with a static repourl which specifies the location of the repository. In addition, an optional branch parameter can be specified to check out code from a specific branch instead of the default master branch. The revision is specified as a SHA1 hash as returned by e.g. gitrev-parse. No attempt is made to ensure that the specified revision is actually a subset of the specified branch.

Monotone is another that follows a decentralized model where each repository can have several branches and tags. The source Step is configured with static repourl and branch parameters, which specifies the location of the repository and the branch to use. The revision is specified as a SHA1 hash as returned by e.g. mtn automate select w:. No attempt is made to ensure that the specified revision is actually a subset of the specified branch.

Name Change Revision Branches
CVS patch [1] timestamp unnamed
Subversion revision integer directories
Git commit sha1 hash named refs
Mercurial changeset sha1 hash different repos or (permanently) named commits
Darcs ? none [2] different repos
Bazaar ? ? ?
Perforce ? ? ?
BitKeeper changeset ? different repos
  • [1] note that CVS only tracks patches to individual files. Buildbot tries to recognize coordinated changes to multiple files by correlating change times.
  • [2] Darcs does not have a concise way of representing a particular revision of the source.
Tree Stability

Changes tend to arrive at a buildmaster in bursts. In many cases, these bursts of changes are meant to be taken together. For example, a developer may have pushed multiple commits to a DVCS that comprise the same new feature or bugfix. To avoid trying to build every change, Buildbot supports the notion of tree stability, by waiting for a burst of changes to finish before starting to schedule builds. This is implemented as a timer, with builds not scheduled until no changes have occurred for the duration of the timer. Choosing a Change Source

There are a variety of ChangeSource classes available, some of which are meant to be used in conjunction with other tools to deliver Change events from the VC repository to the buildmaster.

As a quick guide, here is a list of VC systems and the ChangeSources that might be useful with them. Note that some of these modules are in Buildbot’s master/contrib directory, meaning that they have been offered by other users in hopes they may be useful, and might require some additional work to make them functional.





Bzr (the newer Bazaar)




  • PBChangeSource (listening for connections from monotone-buildbot.lua, which is available with Monotone)

All VC systems can be driven by a PBChangeSource and the buildbot sendchange tool run from some form of commit script. If you write an email parsing function, they can also all be driven by a suitable mail-parsing source. Additionally, handlers for web-based notification (i.e. from GitHub) can be used with WebStatus’ change_hook module. The interface is simple, so adding your own handlers (and sharing!) should be a breeze.

See Change Source Index for a full list of change sources. Configuring Change Sources

The change_source configuration key holds all active change sources for the configuration.

Most configurations have a single ChangeSource, watching only a single tree, e.g.,

from buildbot.plugins import changes

c['change_source'] = changes.PBChangeSource()

For more advanced configurations, the parameter can be a list of change sources:

source1 = ...
source2 = ...
c['change_source'] = [
    source1, source1
Repository and Project

ChangeSources will, in general, automatically provide the proper repository attribute for any changes they produce. For systems which operate on URL-like specifiers, this is a repository URL. Other ChangeSources adapt the concept as necessary.

Many ChangeSources allow you to specify a project, as well. This attribute is useful when building from several distinct codebases in the same buildmaster: the project string can serve to differentiate the different codebases. Schedulers can filter on project, so you can configure different builders to run for each project. Mail-parsing ChangeSources

Many projects publish information about changes to their source tree by sending an email message out to a mailing list, frequently named PROJECT-commits or PROJECT-changes. Each message usually contains a description of the change (who made the change, which files were affected) and sometimes a copy of the diff. Humans can subscribe to this list to stay informed about what’s happening to the source tree.

The Buildbot can also be subscribed to a -commits mailing list, and can trigger builds in response to Changes that it hears about. The buildmaster admin needs to arrange for these email messages to arrive in a place where the buildmaster can find them, and configure the buildmaster to parse the messages correctly. Once that is in place, the email parser will create Change objects and deliver them to the schedulers (see Schedulers) just like any other ChangeSource.

There are two components to setting up an email-based ChangeSource. The first is to route the email messages to the buildmaster, which is done by dropping them into a maildir. The second is to actually parse the messages, which is highly dependent upon the tool that was used to create them. Each VC system has a collection of favorite change-emailing tools, and each has a slightly different format, so each has a different parsing function. There is a separate ChangeSource variant for each parsing function.

Once you’ve chosen a maildir location and a parsing function, create the change source and put it in change_source:

from buildbot.plugins import changes

c['change_source'] = changes.CVSMaildirSource("~/maildir-buildbot",
Subscribing the Buildmaster

The recommended way to install the Buildbot is to create a dedicated account for the buildmaster. If you do this, the account will probably have a distinct email address (perhaps Then just arrange for this account’s email to be delivered to a suitable maildir (described in the next section).

If the Buildbot does not have its own account, extension addresses can be used to distinguish between email intended for the buildmaster and email intended for the rest of the account. In most modern MTAs, the e.g. account has control over every email address at which begins with “foo”, such that email addressed to can be delivered to a different destination than qmail does this by using separate .qmail files for the two destinations (.qmail-foo and .qmail-bar, with .qmail controlling the base address and .qmail-default controlling all other extensions). Other MTAs have similar mechanisms.

Thus you can assign an extension address like to the buildmaster, and retain for your own use.

Using Maildirs

maildir is a simple directory structure originally developed for qmail that allows safe atomic update without locking. Create a base directory with three subdirectories: newtmp, and cur. When messages arrive, they are put into a uniquely-named file (using pids, timestamps, and random numbers) in tmp. When the file is complete, it is atomically renamed into new. Eventually the buildmaster notices the file in new, reads and parses the contents, then moves it into cur. A cronjob can be used to delete files in cur at leisure.

Maildirs are frequently created with the maildirmake tool, but a simple mkdir -p~/MAILDIR/cur,new,tmp is pretty much equivalent.

Many modern MTAs can deliver directly to maildirs. The usual .forward or .procmailrc syntax is to name the base directory with a trailing slash, so something like ~/MAILDIR/. qmail and postfix are maildir-capable MTAs, and procmail is a maildir-capable MDA (Mail Delivery Agent).

Here is an example procmail config, located in ~/.procmailrc:

# .procmailrc
# routes incoming mail to appropriate mailboxes


If procmail is not setup on a system wide basis, then the following one-line .forward file will invoke it.


For MTAs which cannot put files into maildirs directly, the safecat tool can be executed from a .forward file to accomplish the same thing.

The Buildmaster uses the linux DNotify facility to receive immediate notification when the maildir’s new directory has changed. When this facility is not available, it polls the directory for new messages, every 10 seconds by default.

Parsing Email Change Messages

The second component to setting up an email-based ChangeSource is to parse the actual notices. This is highly dependent upon the VC system and commit script in use.

A couple of common tools used to create these change emails, along with the Buildbot tools to parse them, are:

Buildbot CVS MailNotifier

The following sections describe the parsers available for each of these tools.

Most of these parsers accept a prefix= argument, which is used to limit the set of files that the buildmaster pays attention to. This is most useful for systems like CVS and SVN which put multiple projects in a single repository (or use repository names to indicate branches). Each filename that appears in the email is tested against the prefix: if the filename does not start with the prefix, the file is ignored. If the filename does start with the prefix, that prefix is stripped from the filename before any further processing is done. Thus the prefix usually ends with a slash.

class buildbot.changes.mail.CVSMaildirSource

This parser works with the master/contrib/ script.

The script sends an email containing all the files submitted in one directory. It is invoked by using the CVSROOT/loginfo facility.

The Buildbot’s CVSMaildirSource knows how to parse these messages and turn them into Change objects. It takes the directory name of the maildir root. For example:

from buildbot.plugins import changes

c['change_source'] = changes.CVSMaildirSource("/home/buildbot/Mail")

Configuration of CVS and

CVS must be configured to invoke the script when files are checked in. This is done via the CVS loginfo configuration file.

To update this, first do:

cvs checkout CVSROOT

cd to the CVSROOT directory and edit the file loginfo, adding a line like:

SomeModule /cvsroot/CVSROOT/ --cvsroot -e buildbot -P SomeModule %@{sVv@}


For cvs version 1.12.x, the --path %p option is required. Version 1.11.x and 1.12.x report the directory path differently.

The above example you put the script under /cvsroot/CVSROOT. It can be anywhere. Run the script with --help to see all the options. At the very least, the options -e (email) and -P (project) should be specified. The line must end with %{sVv}. This is expanded to the files that were modified.

Additional entries can be added to support more modules.

See --help for more information on the available options.

class buildbot.changes.mail.SVNCommitEmailMaildirSource

SVNCommitEmailMaildirSource parses message sent out by the script, which is included in the Subversion distribution.

It does not currently handle branches: all of the Change objects that it creates will be associated with the default (i.e. trunk) branch.

from buildbot.plugins import changes

c['change_source'] = changes.SVNCommitEmailMaildirSource("~/maildir-buildbot")
class buildbot.changes.mail.BzrLaunchpadEmailMaildirSource

BzrLaunchpadEmailMaildirSource parses the mails that are sent to addresses that subscribe to branch revision notifications for a bzr branch hosted on Launchpad.

The branch name defaults to lp:Launchpad path. For example lp:~maria-captains/maria/5.1.

If only a single branch is used, the default branch name can be changed by setting defaultBranch.

For multiple branches, pass a dictionary as the value of the branchMap option to map specific repository paths to specific branch names (see example below). The leading lp: prefix of the path is optional.

The prefix option is not supported (it is silently ignored). Use the branchMap and defaultBranch instead to assign changes to branches (and just do not subscribe the Buildbot to branches that are not of interest).

The revision number is obtained from the email text. The bzr revision id is not available in the mails sent by Launchpad. However, it is possible to set the bzr append_revisions_only option for public shared repositories to avoid new pushes of merges changing the meaning of old revision numbers.

from buildbot.plugins import changes

bm = {
    'lp:~maria-captains/maria/5.1': '5.1',
    'lp:~maria-captains/maria/6.0': '6.0'
c['change_source'] = changes.BzrLaunchpadEmailMaildirSource("~/maildir-buildbot",
                                                            branchMap=bm) PBChangeSource
class buildbot.changes.pb.PBChangeSource

PBChangeSource actually listens on a TCP port for clients to connect and push change notices into the Buildmaster. This is used by the built-in buildbot sendchange notification tool, as well as several version-control hook scripts. This change is also useful for creating new kinds of change sources that work on a push model instead of some kind of subscription scheme, for example a script which is run out of an email .forward file. This ChangeSource always runs on the same TCP port as the workers. It shares the same protocol, and in fact shares the same space of “usernames”, so you cannot configure a PBChangeSource with the same name as a worker.

If you have a publicly accessible worker port, and are using PBChangeSourceyou must establish a secure username and password for the change source. If your sendchange credentials are known (e.g., the defaults), then your buildmaster is susceptible to injection of arbitrary changes, which (depending on the build factories) could lead to arbitrary code execution on workers.

The PBChangeSource is created with the following arguments.

which port to listen on. If None (which is the default), it shares the port used for worker connections.
The user account that the client program must use to connect. Defaults to change
The password for the connection - defaults to changepw. Can be a Secret. Do not use this default on a publicly exposed port!

The prefix to be found and stripped from filenames delivered over the connection, defaulting to None. Any filenames which do not start with this prefix will be removed. If all the filenames in a given Change are removed, the that whole Change will be dropped. This string should probably end with a directory separator.

This is useful for changes coming from version control systems that represent branches as parent directories within the repository (like SVN and Perforce). Use a prefix of trunk/ or project/branches/foobranch/ to only follow one branch and to get correct tree-relative filenames. Without a prefix, the PBChangeSource will probably deliver Changes with filenames like trunk/foo.cinstead of just foo.c. Of course this also depends upon the tool sending the Changes in (like buildbot sendchange) and what filenames it is delivering: that tool may be filtering and stripping prefixes at the sending end.

For example:

from buildbot.plugins import changes

c['change_source'] = changes.PBChangeSource(port=9999, user='laura', passwd='fpga')

The following hooks are useful for sending changes to a PBChangeSource:

Bzr Hook

Bzr is also written in Python, and the Bzr hook depends on Twisted to send the changes.

To install, put master/contrib/ in one of your plugins locations a bzr plugins directory (e.g., ~/.bazaar/plugins). Then, in one of your bazaar conf files (e.g., ~/.bazaar/locations.conf), set the location you want to connect with Buildbot with these keys:

  • buildbot_on one of ‘commit’, ‘push, or ‘change’. Turns the plugin on to report changes via commit, changes via push, or any changes to the trunk. ‘change’ is recommended.
  • buildbot_server (required to send to a Buildbot master) the URL of the Buildbot master to which you will connect (as of this writing, the same server and port to which workers connect).
  • buildbot_port (optional, defaults to 9989) the port of the Buildbot master to which you will connect (as of this writing, the same server and port to which workers connect)
  • buildbot_pqm (optional, defaults to not pqm) Normally, the user that commits the revision is the user that is responsible for the change. When run in a pqm (Patch Queue Manager, see environment, the user that commits is the Patch Queue Manager, and the user that committed the parentrevision is responsible for the change. To turn on the pqm mode, set this value to any of (case-insensitive) “Yes”, “Y”, “True”, or “T”.
  • buildbot_dry_run (optional, defaults to not a dry run) Normally, the post-commit hook will attempt to communicate with the configured Buildbot server and port. If this parameter is included and any of (case-insensitive) “Yes”, “Y”, “True”, or “T”, then the hook will simply print what it would have sent, but not attempt to contact the Buildbot master.
  • buildbot_send_branch_name (optional, defaults to not sending the branch name) If your Buildbot’s bzr source build step uses a repourl, do not turn this on. If your buildbot’s bzr build step uses a baseURL, then you may set this value to any of (case-insensitive) “Yes”, “Y”, “True”, or “T” to have the Buildbot master append the branch name to the baseURL.


The bzr smart server (as of version 2.2.2) doesn’t know how to resolve bzr:// urls into absolute paths so any paths in locations.conf won’t match, hence no change notifications will be sent to Buildbot. Setting configuration parameters globally or in-branch might still work. When Buildbot no longer has a hardcoded password, it will be a configuration option here as well.

Here’s a simple example that you might have in your ~/.bazaar/locations.conf.

buildbot_on = change
buildbot_server = localhost P4Source

The P4Source periodically polls a Perforce depot for changes. It accepts the following arguments:

The Perforce server to connect to (as host:port).
The Perforce user.
The Perforce password.
The base depot path to watch, without the trailing ‘/…’.
An optional string parameter. Specify the location of the perforce command line binary (p4). You only need to do this if the perforce binary is not in the path of the Buildbot user. Defaults to p4.
A function that maps a pathname, without the leading p4base, to a (branch, filename) tuple. The default just returns (None, branchfile), which effectively disables branch support. You should supply a function which understands your repository structure.
How often to poll, in seconds. Defaults to 600 (10 minutes).
Set the name of the project to be used for the P4Source. This will then be set in any changes generated by the P4Source, and can be used in a Change Filter for triggering particular builders.
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
The maximum number of changes to inspect at a time. If more than this number occur since the last poll, older changes will be silently ignored.
The character encoding of p4’s output. This defaults to “utf8”, but if your commit messages are in another encoding, specify that here. For example, if you’re using Perforce on Windows, you may need to use “cp437” as the encoding if “utf8” generates errors in your master log.
The timezone of the Perforce server, using the usual timezone format (e.g: "Europe/Stockholm") in case it’s not in UTC.
Set to True to use ticket-based authentication, instead of passwords (but you still need to specify p4passwd).
How often to get a new ticket, in seconds, when use_tickets is enabled. Defaults to 86400 (24 hours).
A function that maps branch and revision to a valid url (e.g. p4web), stored along with the change. This function must be a callable which takes two arguments, the branch and the revision. Defaults to lambda branch, revision: (u’‘)
A function that resolves the Perforce ‘user@workspace’ into a more verbose form, stored as the author of the change. Useful when usernames do not match email addresses and external, client-side lookup is required. This function must be a callable which takes one argument. Defaults to lambda who: (who)
Example #1

This configuration uses the P4PORTP4USER, and P4PASSWD specified in the buildmaster’s environment. It watches a project in which the branch name is simply the next path component, and the file is all path components after.

from buildbot.plugins import changes

s = changes.P4Source(p4base='//depot/project/',
                     split_file=lambda branchfile: branchfile.split('/',1))
c['change_source'] = s
Example #2

Similar to the previous example but also resolves the branch and revision into a valid revlink.

from buildbot.plugins import changes

s = changes.P4Source(p4base='//depot/project/',
                     split_file=lambda branchfile: branchfile.split('/',1))
                     revlink=lambda branch, revision: 'http://p4web:8080/@md=d&@/{}?ac=10'.format(revision)
c['change_source'] = s SVNPoller
class buildbot.changes.svnpoller.SVNPoller

The SVNPoller is a ChangeSource which periodically polls a Subversion repository for new revisions, by running the svn log command in a subshell. It can watch a single branch or multiple branches.

SVNPoller accepts the following arguments:


The base URL path to watch, like svn://, or, or even file:///home/svn/Repository/ProjectA/branches/1.5/. This must include the access scheme, the location of the repository (both the hostname for remote ones, and any additional directory names necessary to get to the repository), and the sub-path within the repository’s virtual filesystem for the project and branch of interest.

The SVNPoller will only pay attention to files inside the subdirectory specified by the complete repourl.


A function to convert pathnames into (branch, relative_pathname) tuples. Use this to explain your repository’s branch-naming policy to SVNPoller. This function must accept a single string (the pathname relative to the repository) and return a two-entry tuple. Directory pathnames always end with a right slash to distinguish them from files, like trunk/src/, or src/. There are a few utility functions in buildbot.changes.svnpoller that can be used as a split_file function; see below for details.

For directories, the relative pathname returned by split_file should end with a right slash but an empty string is also accepted for the root, like ("branches/1.5.x", "") being converted from "branches/1.5.x/".

The default value always returns (None, path), which indicates that all files are on the trunk.

Subclasses of SVNPoller can override the split_file method instead of using the split_file=argument.

Set the name of the project to be used for the SVNPoller. This will then be set in any changes generated by the SVNPoller, and can be used in a Change Filter for triggering particular builders.
An optional string parameter. If set, the option –user argument will be added to all svncommands. Use this if you have to authenticate to the svn server before you can do svn info or svn log commands. Can be a Secret.
Like svnuser, this will cause a option –password argument to be passed to all svn commands. Can be a Secret.
How often to poll, in seconds. Defaults to 600 (checking once every 10 minutes). Lower this if you want the Buildbot to notice changes faster, raise it if you want to reduce the network and CPU load on your svn server. Please be considerate of public SVN repositories by using a large interval when polling them.
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
The maximum number of changes to inspect at a time. Every pollInterval seconds, the SVNPollerasks for the last histmax changes and looks through them for any revisions it does not already know about. If more than histmax revisions have been committed since the last poll, older changes will be silently ignored. Larger values of histmax will cause more time and memory to be consumed on each poll attempt. histmax defaults to 100.
This controls the svn executable to use. If subversion is installed in a weird place on your system (outside of the buildmaster’s PATH), use this to tell SVNPoller where to find it. The default value of svn will almost always be sufficient.
This parameter is deprecated in favour of specifying a global revlink option. This parameter allows a link to be provided for each revision (for example, to websvn or viewvc). These links appear anywhere changes are shown, such as on build or change pages. The proper form for this parameter is an URL with the portion that will substitute for a revision number replaced by ‘’%s’‘. For example, 'http://myserver/websvn/revision.php?rev=%s' could be used to cause revision links to be created to a websvn repository viewer.
If specified, this is a pathname of a cache file that SVNPoller will use to store its state between restarts of the master.
If specified, the extra arguments will be added to the svn command args.

Several split file functions are available for common SVN repository layouts. For a poller that is only monitoring trunk, the default split file function is available explicitly as split_file_alwaystrunk:

from buildbot.plugins import changes, util

c['change_source'] = changes.SVNPoller(

For repositories with the /trunk and /branches/BRANCH layout, split_file_branches will do the job:

from buildbot.plugins import changes, util

c['change_source'] = changes.SVNPoller(

When using this splitter the poller will set the project attribute of any changes to the project attribute of the poller.

For repositories with the PROJECT/trunk and PROJECT/branches/BRANCH layout, split_file_projects_branches will do the job:

from buildbot.plugins import changes, util

c['change_source'] = changes.SVNPoller(

When using this splitter the poller will set the project attribute of any changes to the project determined by the splitter.

The SVNPoller is highly adaptable to various Subversion layouts. See Customizing SVNPoller for details and some common scenarios. Bzr Poller

If you cannot insert a Bzr hook in the server, you can use the BzrPoller. To use it, put master/contrib/ somewhere that your Buildbot configuration can import it. Even putting it in the same directory as the master.cfg should work. Install the poller in the Buildbot configuration as with any other change source. Minimally, provide a URL that you want to poll (bzr://bzr+ssh://, or lp:), making sure the Buildbot user has necessary privileges.

# put file to the same directory as master.cfg
from bzr_buildbot import BzrPoller

c['change_source'] = BzrPoller(

The BzrPoller parameters are:

The URL to poll.
The number of seconds to wait between polls. Defaults to 10 minutes.
Any value to be used as the branch name. Defaults to None, or specify a string, or specify the constants from SHORT or FULL to get the short branch name or full branch address.
normally, the user that commits the revision is the user that is responsible for the change. When run in a pqm (Patch Queue Manager, see environment, the user that commits is the Patch Queue Manager, and the user that committed the merged, parent revision is responsible for the change. Set this value to True if this is pointed against a PQM-managed branch. GitPoller

If you cannot take advantage of post-receive hooks as provided by master/contrib/ for example, then you can use the GitPoller.

The GitPoller periodically fetches from a remote Git repository and processes any changes. It requires its own working directory for operation. The default should be adequate, but it can be overridden via the workdir property.


There can only be a single GitPoller pointed at any given repository.

The GitPoller requires Git-1.7 and later. It accepts the following arguments:

the git-url that describes the remote repository, e.g. (see the git fetch help for more info on git-url formats)

One of the following:

  • a list of the branches to fetch.
  • True indicating that all branches should be fetched
  • a callable which takes a single argument. It should take a remote refspec (such as 'refs/heads/master', and return a boolean indicating whether that branch should be fetched.
accepts a single branch name to fetch. Exists for backwards compatibility with old configurations.
interval in seconds between polls, default is 10 minutes
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
Determine if a push on a new branch or update of an already known branch with already known commits should trigger a build. This is useful in case you have build steps depending on the name of the branch and you use topic branches for development. When you merge your topic branch into “master” (for instance), a new build will be triggered. (defaults to False).
path to the Git binary, defaults to just 'git'
Set the category to be used for the changes produced by the GitPoller. This will then be set in any changes generated by the GitPoller, and can be used in a Change Filter for triggering particular builders.
Set the name of the project to be used for the GitPoller. This will then be set in any changes generated by the GitPoller, and can be used in a Change Filter for triggering particular builders.
parse each revision’s commit timestamp (default is True), or ignore it in favor of the current time (so recently processed commits appear together in the waterfall page)
Set encoding will be used to parse author’s name and commit message. Default encoding is 'utf-8'. This will not be applied to file names since Git will translate non-ascii file names to unreadable escape sequences.
the directory where the poller should keep its local repository. The default is gitpoller_work. If this is a relative path, it will be interpreted relative to the master’s basedir. Multiple Git pollers can share the same directory.
Determines if the GitPoller should poll for new tags in the git repository.
Specifies private SSH key for git to use. This may be either a Secret or just a string. This option requires Git-2.3 or later. The master must either have the host in the known hosts file or the host key must be specified via the sshHostKey option.
Specifies public host key to match when authenticating with SSH public key authentication. This may be either a Secret or just a string. sshPrivateKey must be specified in order to use this option. The host key must be in the form of <key type> <base64-encoded string>, e.g. ssh-rsa AAAAB3N<…>FAaQ==.

A configuration for the Git poller might look like this:

from buildbot.plugins import changes

c['change_source'] = changes.GitPoller(repourl='',
                                       branches=['master', 'great_new_feature']) HgPoller

The HgPoller periodically pulls a named branch from a remote Mercurial repository and processes any changes. It requires its own working directory for operation, which must be specified via the workdir property.

The HgPoller requires a working hg executable, and at least a read-only access to the repository it polls (possibly through ssh keys or by tweaking the hgrc of the system user Buildbot runs as).

The HgPoller will not transmit any change if there are several heads on the watched named branch. This is similar (although not identical) to the Mercurial executable behaviour. This exceptional condition is usually the result of a developer mistake, and usually does not last for long. It is reported in logs. If fixed by a later merge, the buildmaster administrator does not have anything to do: that merge will be transmitted, together with the intermediate ones.

The HgPoller accepts the following arguments:

the name of the poller. This must be unique, and defaults to the repourl.
the url that describes the remote repository, e.g. Any url suitable for hg pull can be specified.
the desired branch to pull, will default to 'default'

the directory where the poller should keep its local repository. It is mandatory for now, although later releases may provide a meaningful default.

It also serves to identify the poller in the buildmaster internal database. Changing it may result in re-processing all changes so far.

Several HgPoller instances may share the same workdir for mutualisation of the common history between two different branches, thus easing on local and remote system resources and bandwidth.

If relative, the workdir will be interpreted from the master directory.

interval in seconds between polls, default is 10 minutes
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
path to the Mercurial binary, defaults to just 'hg'
Set the category to be used for the changes produced by the HgPoller. This will then be set in any changes generated by the HgPoller, and can be used in a Change Filter for triggering particular builders.
Set the name of the project to be used for the HgPoller. This will then be set in any changes generated by the HgPoller, and can be used in a Change Filter for triggering particular builders.
parse each revision’s commit timestamp (default is True), or ignore it in favor of the current time (so recently processed commits appear together in the waterfall page)
Set encoding will be used to parse author’s name and commit message. Default encoding is 'utf-8'.

A configuration for the Mercurial poller might look like this:

from buildbot.plugins import changes

c['change_source'] = changes.HgPoller(repourl='',
                                      workdir='hg-myrepo') GitHubPullrequestPoller
class buildbot.changes.github.GitHubPullrequestPoller

This GitHubPullrequestPoller periodically polls the GitHub API for new or updated pull requests. The authorrevisionrevlinkbranch and files fields in the recorded changes are populated with information extracted from the pull request. This allows to filter for certain changes in files and create a blamelist based on the authors in the GitHub pull request.

The GitHubPullrequestPoller accepts the following arguments:

The owner of the GitHub repository. This argument is required.
The name of the GitHub repository. This argument is required.
List of branches to accept as base branch (e.g. master). Defaults to None and accepts all branches as base.
Poll interval between polls in seconds. Default is 10 minutes.
Whether to poll on startup of the buildbot master. Default is False and first poll will occur pollInterval seconds after the master start.
Set the category to be used for the changes produced by the GitHubPullrequestPoller. This will then be set in any changes generated by the GitHubPullrequestPoller, and can be used in a Change Filter for triggering particular builders.
GitHub API endpoint. Default is
A callable which takes a dict which contains the decoded JSON object of the GitHub pull request as argument. All fields specified by the GitHub API are accessible. If the callable returns False the pull request is ignored. Default is True which does not filter any pull requests.
A GitHub API token to execute all requests to the API authenticated. It is strongly recommended to use a API token since it increases GitHub API rate limits significantly.
Set which type of repository link will be in the repository property. Possible values httpssvngitor svn. This link can then be used in a Source Step to checkout the source.
Set to True if the changes should contain refs/pulls/<PR #>/merge in the branch property and a link to the base repository in the repository property. These properties can be used by the GitHubsource to pull from the special branch in the base repository. Default is False.
A list of fnmatch expressions which match against the flattened pull request information JSON prefixed with github. For example github.number represents the pull request number. Available entries can be looked up in the GitHub API Documentation or by examining the data returned for a pull request by the API. BitbucketPullrequestPoller
class buildbot.changes.bitbucket.BitbucketPullrequestPoller

This BitbucketPullrequestPoller periodically polls Bitbucket for new or updated pull requests. It uses Bitbuckets powerful Pull Request REST API to gather the information needed.

The BitbucketPullrequestPoller accepts the following arguments:

The owner of the Bitbucket repository. All Bitbucket Urls are of the form
The name of the Bitbucket repository.
A single branch or a list of branches which should be processed. If it is None (the default) all pull requests are used.
Interval in seconds between polls, default is 10 minutes.
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
Set the category to be used for the changes produced by the BitbucketPullrequestPoller. This will then be set in any changes generated by the BitbucketPullrequestPoller, and can be used in a Change Filter for triggering particular builders.
Set the name of the project to be used for the BitbucketPullrequestPoller. This will then be set in any changes generated by the BitbucketPullrequestPoller, and can be used in a Change Filter for triggering particular builders.
A callable which takes one parameter, the decoded Python object of the pull request JSON. If the it returns False the pull request is ignored. It can be used to define custom filters based on the content of the pull request. See the Bitbucket documentation for more information about the format of the response. By default the filter always returns True.
parse each revision’s commit timestamp (default is True), or ignore it in favor of the current time (so recently processed commits appear together in the waterfall page)
Set encoding will be used to parse author’s name and commit message. Default encoding is 'utf-8'.

A minimal configuration for the Bitbucket pull request poller might look like this:

from buildbot.plugins import changes

c['change_source'] = changes.BitbucketPullrequestPoller(

Here is a more complex configuration using a pullrequest_filter. The pull request is only processed if at least 3 people have already approved it:

def approve_filter(pr, threshold):
    approves = 0
    for participant in pr['participants']:
        if participant['approved']:
            approves = approves + 1

    if approves < threshold:
        return False
    return True

from buildbot.plugins import changes
c['change_source'] = changes.BitbucketPullrequestPoller(
    pullrequest_filter=lambda pr : approve_filter(pr,3),


Anyone who can create pull requests for the Bitbucket repository can initiate a change, potentially causing the buildmaster to run arbitrary code. GerritChangeSource
class buildbot.changes.gerritchangesource.GerritChangeSource

The GerritChangeSource class connects to a Gerrit server by its SSH interface and uses its event source mechanism, gerrit stream-events.

The GerritChangeSource accepts the following arguments:

the dns or ip that host the Gerrit ssh server
the port of the Gerrit ssh server
the username to use to connect to Gerrit
ssh identity file to for authentication (optional). Pay attention to the ssh passphrase
event to be handled (optional). By default processes patchset-created and ref-updated
Print Gerrit event in the log (default False). This allows to debug event content, but will eventually fill your logs with useless Gerrit event logs.

By default this class adds a change to the Buildbot system for each of the following events:

A change is proposed for review. Automatic checks like can be automatically triggered. Beware of what kind of automatic task you trigger. At this point, no trusted human has reviewed the code, and a patch could be specially crafted by an attacker to compromise your workers.
A change has been merged into the repository. Typically, this kind of event can lead to a complete rebuild of the project, and upload binaries to an incremental build results server.

But you can specify how to handle events:

  • Any event with change and patchSet will be processed by universal collector by default.
  • In case you’ve specified processing function for the given kind of events, all events of this kind will be processed only by this function, bypassing universal collector.

An example:

from buildbot.plugins import changes

class MyGerritChangeSource(changes.GerritChangeSource):
    """Custom GerritChangeSource
    def eventReceived_patchset_created(self, properties, event):
        """Handler events without properties
        properties = {}
        self.addChangeFromEvent(properties, event)

This class will populate the property list of the triggered build with the info received from Gerrit server in JSON format.


If you selected GerritChangeSource, you must use Gerrit source step: the branch property of the change will be target_branch/change_id and such a ref cannot be resolved, so the Git source step would fail.

In case of patchset-created event, these properties will be:

Branch of the Change
Change’s ID in the Gerrit system (the ChangeId: in commit comments)
Change’s number in Gerrit system
Change’s owner email (owner is first uploader)
Change’s owner name
Project of the Change
Change’s subject
URL of the Change in the Gerrit’s web interface
Patchset’s version number
Patchset’s Gerrit “virtual branch”
Patchset’s Git commit ID
Patchset uploader’s email (owner is first uploader)
Patchset uploader’s name (owner is first uploader)
Event type (patchset-created)
Patchset uploader’s email
Patchset uploader’s name

In case of ref-updated event, these properties will be:

New Git commit ID (after merger)
Previous Git commit ID (before merger)
Project that was updated
Branch that was updated
Submitter’s email (merger responsible)
Submitter’s name (merger responsible)
Event type (ref-updated)
Submitter’s email (merger responsible)
Submitter’s name (merger responsible)

A configuration for this source might look like:

from buildbot.plugins import changes

c['change_source'] = changes.GerritChangeSource(
    handled_events=["patchset-created", "change-merged"])

See master/docs/examples/git_gerrit.cfg or master/docs/examples/repo_gerrit.cfg in the Buildbot distribution for a full example setup of Git+Gerrit or Repo+Gerrit of GerritChangeSource. GerritEventLogPoller
class buildbot.changes.gerritchangesource.GerritEventLogPoller

The GerritEventLogPoller class is similar to GerritChangeSource but connects to the Gerrit server by its HTTP interface and uses the events-log plugin.

The GerritEventLogPoller accepts the following arguments:

the HTTP url where to find Gerrit
a requests authentication configuration. if Gerrit is configured with BasicAuth, then it shall be ('login', 'password') if Gerrit is configured with DigestAuth, then it shall be requests.auth.HTTPDigestAuth('login', 'password') from the requests module.
event to be handled (optional). By default processes patchset-created and ref-updated
interval in seconds between polls, default is 30 seconds
Determines when the first poll occurs. True = immediately on launch (default), False = wait for one pollInterval.
The git URL where Gerrit is accessible via git+ssh protocol
Print Gerrit event in the log (default False). This allows to debug event content, but will eventually fill your logs with useless Gerrit event logs.

The same customization can be done as GerritChangeSource for handling special events. GerritChangeFilter
class buildbot.changes.gerritchangesource.GerritChangeFilter

GerritChangeFilter is a ready to use ChangeFilter you can pass to AnyBranchScheduler in order to filter changes, to create pre-commit builders or post-commit schedulers. It has the same api as Change Filter, except it has additional eventtype set of filter (can as well be specified as value, list, regular expression or callable)

An example is following:

from buildbot.plugins import schedulers, util

# this scheduler will create builds when a patch is uploaded to gerrit
# but only if it is uploaded to the "main" branch

# this scheduler will create builds when a patch is merged in the "main" branch
# for post-commit tests
                              change_filter=util.GerritChangeFilter("main", "ref-updated"),
                              builderNames=["main-postcommit"]) Change Hooks (HTTP Notifications)

Buildbot already provides a web frontend, and that frontend can easily be used to receive HTTP push notifications of commits from services like GitHub. See Change Hooks for more information.

2.5.4. Changes

class buildbot.changes.changes.Change

Change is an abstract way Buildbot uses to represent a single change to the source files performed by a developer. In version control systems that support the notion of atomic check-ins a change represents a changeset or commit. Instances of Change have the following attributes. Who

Each Change has a who attribute, which specifies which developer is responsible for the change. This is a string which comes from a namespace controlled by the VC repository. Frequently this means it is a username on the host which runs the repository, but not all VC systems require this. Each StatusNotifier will map the who attribute into something appropriate for their particular means of communication: an email address, an IRC handle, etc.

This who attribute is also parsed and stored into Buildbot’s database (see User Objects). Currently, only who attributes in Changes from git repositories are translated into user objects, but in the future all incoming Changes will have their who parsed and stored. Files

It also has a list of files, which are just the tree-relative filenames of any files that were added, deleted, or modified for this Change. These filenames are used by the fileIsImportant function (in the scheduler) to decide whether it is worth triggering a new build or not, e.g. the function could use the following function to only run a build if a C file were checked in:

def has_C_files(change):
    for name in change.files:
        if name.endswith(".c"):
            return True
    return False

Certain BuildSteps can also use the list of changed files to run a more targeted series of tests, e.g. the python_twisted.Trial step can run just the unit tests that provide coverage for the modified .py files instead of running the full test suite. Comments

The Change also has a comments attribute, which is a string containing any checkin comments. Project

The project attribute of a change or source stamp describes the project to which it corresponds, as a short human-readable string. This is useful in cases where multiple independent projects are built on the same buildmaster. In such cases, it can be used to control which builds are scheduled for a given commit, and to limit status displays to only one project. Repository

This attribute specifies the repository in which this change occurred. In the case of DVCS’s, this information may be required to check out the committed source code. However, using the repository from a change has security risks: if Buildbot is configured to blindly trust this information, then it may easily be tricked into building arbitrary source code, potentially compromising the workers and the integrity of subsequent builds. Codebase

This attribute specifies the codebase to which this change was made. As described in source stampssection, multiple repositories may contain the same codebase. A change’s codebase is usually determined by the codebaseGenerator configuration. By default the codebase is ‘’; this value is used automatically for single-codebase configurations. Revision

Each Change can have a revision attribute, which describes how to get a tree with a specific state: a tree which includes this Change (and all that came before it) but none that come after it. If this information is unavailable, the revision attribute will be None. These revisions are provided by the ChangeSource.

Revisions are always strings.

revision is the seconds since the epoch as an integer.
revision is the revision number
revision is a large string, the output of darcs changes --context
revision is a short string (a hash ID), the output of hg identify
revision is the transaction number
revision is a short string (a SHA1 hash), the output of e.g. git rev-parse Branches

The Change might also have a branch attribute. This indicates that all of the Change’s files are in the same named branch. The schedulers get to decide whether the branch should be built or not.

For VC systems like CVS, Git, Mercurial and Monotone the branch name is unrelated to the filename. (That is, the branch name and the filename inhabit unrelated namespaces.) For SVN, branches are expressed as subdirectories of the repository, so the file’s repourl is a combination of some base URL, the branch name, and the filename within the branch. (In a sense, the branch name and the filename inhabit the same namespace.) Darcs branches are subdirectories of a base URL just like SVN.

branch=’warner-newfeature’, files=[‘src/foo.c’]
branch=’branches/warner-newfeature’, files=[‘src/foo.c’]
branch=’warner-newfeature’, files=[‘src/foo.c’]
branch=’warner-newfeature’, files=[‘src/foo.c’]
branch=’warner-newfeature’, files=[‘src/foo.c’]
branch=’warner-newfeature’, files=[‘src/foo.c’] Change Properties

A Change may have one or more properties attached to it, usually specified through the Force Build form or sendchange. Properties are discussed in detail in the Build Properties section.

2.5.5. Schedulers

Schedulers are responsible for initiating builds on builders.

Some schedulers listen for changes from ChangeSources and generate build sets in response to these changes. Others generate build sets without changes, based on other events in the buildmaster. Configuring Schedulers

The schedulers configuration parameter gives a list of scheduler instances, each of which causes builds to be started on a particular set of Builders. The two basic scheduler classes you are likely to start with are SingleBranchScheduler and Periodic, but you can write a customized subclass to implement more complicated build scheduling.

Scheduler arguments should always be specified by name (as keyword arguments), to allow for future expansion:

sched = SingleBranchScheduler(name="quick", builderNames=['lin', 'win'])

There are several common arguments for schedulers, although not all are available with all schedulers.

Each Scheduler must have a unique name. This is used in status displays, and is also available in the build property scheduler.

This is the set of builders which this scheduler should trigger, specified as a list of names (strings). This can also be an IRenderable object which will render to a list of builder names (or a list of IRenderable that will render to builder names).


When builderNames is rendered, these additional Properties attributes are available:

A reference to the BuildMaster object that owns this scheduler. This can be used to access the data API.
The list of sourcestamps that triggered the scheduler.
The list of changes associated with the sourcestamps.
The list of modified files associated with the changes.

Any property attached to the change(s) that triggered the scheduler will be combined and available when rendering builderNames.

Here is a simple example:

from buildbot.plugins import util, schedulers

def builderNames(props):
    builders = set()
    for f in props.files:
        if f.endswith('.rst'):
        if f.endswith('.c'):
    return list(builders)

c['schedulers'] = [

And a more complex one:

import fnmatch

from twisted.internet import defer

from buildbot.plugins import util, schedulers

def builderNames(props):
    # If "buildername_pattern" is defined with "buildbot sendchange",
    # check if the builder name matches it.
    pattern = props.getProperty('buildername_pattern')

    # If "builder_tags" is defined with "buildbot sendchange",
    # only schedule builders that have the specified tags.
    tags = props.getProperty('builder_tags')

    builders = []

    for b in (yield'builders',))):
        if pattern and not fnmatch.fnmatchcase(b['name'], pattern):
        if tags and not set(tags.split()).issubset(set(b['tags'])):


c['schedulers'] = [
properties (optional)

This is a dictionary specifying properties that will be transmitted to all builds started by this scheduler. The owner property may be of particular interest, as its contents (as a list) will be added to the list of “interested users” (Doing Things With Users) for each triggered build. For example

sched = Scheduler(...,
    properties = {
        'owner': ['', '']
codebases (optional)

Specifies codebase definitions that are used when the scheduler processes data from more than one repository at the same time.

The codebases parameter is only used to fill in missing details about a codebases when scheduling a build. For example, when a change to codebase A occurs, a scheduler must invent a sourcestamp for codebase B. Source steps that specify codebase B as their codebase will use the invented timestamp.

The parameter does not act as a filter on incoming changes – use a change filter for that purpose.

This parameter can be specified in two forms:

  • as a list of strings. This is the Simplest form, use it if no special overrides are needed. In this form, just the names of the codebases are listed.
  • as a dictionary of dictionaries. In this form, the per-codebase overrides of repository, branch and revision can be specified.

Each codebase definition dictionary is a dictionary with any of the keys: repositorybranchrevision. The codebase definitions are combined in a dictionary keyed by the name of the codebase.

codebases = {'codebase1': {'repository':'....',
                           'revision': None},
             'codebase2': {'repository':'....'} }
fileIsImportant (optional)
A callable which takes one argument, a Change instance, and returns True if the change is worth building, and False if it is not. Unimportant Changes are accumulated until the build is triggered by an important change. The default value of None means that all Changes are important.
change_filter (optional)
The change filter that will determine which changes are recognized by this scheduler; Change Filters. Note that this is different from fileIsImportant: if the change filter filters out a Change, then it is completely ignored by the scheduler. If a Change is allowed by the change filter, but is deemed unimportant, then it will not cause builds to start, but will be remembered and shown in status displays. The default value of None does not filter any changes at all.
onlyImportant (optional)
A boolean that, when True, only adds important changes to the buildset as specified in the fileIsImportant callable. This means that unimportant changes are ignored the same way a change_filter filters changes. This defaults to False and only applies when fileIsImportant is given.
reason (optional)
A string that will be used as the reason for the triggered build. By default it lists the type and name of the scheduler triggering the build.

The remaining subsections represent a catalog of the available scheduler types. All these schedulers are defined in modules under buildbot.schedulers, and the docstrings there are the best source of documentation on the arguments taken by each one. Scheduler Resiliency

In a multi-master configuration, schedulers with the same name can be configured on multiple masters. Only one instance of the scheduler will be active. If that instance becomes inactive, due to its master being shut down or failing, then another instance will become active after a short delay. This provides resiliency in scheduler configurations, so that schedulers are not a single point of failure in a Buildbot infrastructure.

The Data API and web UI display the master on which each scheduler is running.

There is currently no mechanism to control which master’s scheduler instance becomes active. The behavior is nondeterministic, based on the timing of polling by inactive schedulers. The failover is non-revertive. Change Filters

Several schedulers perform filtering on an incoming set of changes. The filter can most generically be specified as a ChangeFilter. Set up a ChangeFilter like this:

from buildbot.plugins import util
my_filter = util.ChangeFilter(project_re="^baseproduct/.*", branch="devel")

and then add it to a scheduler with the change_filter parameter:

sch = SomeSchedulerClass(...,

There are five attributes of changes on which you can filter:

the project string, as defined by the ChangeSource.
the repository in which this change occurred.
the branch on which this change occurred. Note that ‘trunk’ or ‘master’ is often denoted by None.
the category, again as defined by the ChangeSource.
the change’s codebase.

For each attribute, the filter can look for a single, specific value:

my_filter = util.ChangeFilter(project='myproject')

or accept any of a set of values:

my_filter = util.ChangeFilter(project=['myproject', 'jimsproject'])

or apply a regular expression, using the attribute name with a “_re” suffix:

my_filter = util.ChangeFilter(category_re='.*deve.*')
# or, to use regular expression flags:
import re
my_filter = util.ChangeFilter(category_re=re.compile('.*deve.*', re.I))

buildbot.www.hooks.github.GitHubEventHandler has a special github_distinct property that can be used to filter whether or not non-distinct changes should be considered. For example, if a commit is pushed to a branch that is not being watched and then later pushed to a watched branch, by default, this will be recorded as two separate Changes. In order to record a change only the first time the commit appears, you can install a custom ChangeFilter like this:

ChangeFilter(filter_fn = lambda c:'github_distinct')

For anything more complicated, define a Python function to recognize the strings you want:

def my_branch_fn(branch):
    return branch in branches_to_build and branch not in branches_to_ignore
my_filter = util.ChangeFilter(branch_fn=my_branch_fn)

The special argument filter_fn can be used to specify a function that is given the entire Change object, and returns a boolean.

The entire set of allowed arguments, then, is

project project_re project_fn
repository repository_re repository_fn
branch branch_re branch_fn
category category_re category_fn
codebase codebase_re codebase_fn

A Change passes the filter only if all arguments are satisfied. If no filter object is given to a scheduler, then all changes will be built (subject to any other restrictions the scheduler enforces). Scheduler Types

The remaining subsections represent a catalog of the available Scheduler types. All these Schedulers are defined in modules under buildbot.schedulers, and the docstrings there are the best source of documentation on the arguments taken by each one.


This is the original and still most popular scheduler class. It follows exactly one branch, and starts a configurable tree-stable-timer after each change on that branch. When the timer expires, it starts a build on some set of Builders. This scheduler accepts a fileIsImportant function which can be used to ignore some Changes if they do not affect any important files.

If treeStableTimer is not set, then this scheduler starts a build for every Change that matches its change_filter and statsfies fileIsImportant. If treeStableTimer is set, then a build is triggered for each set of Changes which arrive within the configured time, and match the filters.


The behavior of this scheduler is undefined, if treeStableTimer is set, and changes from multiple branches, repositories or codebases are accepted by the filter.


The codebases argument will filter out codebases not specified there, but won’t filter based on the branches specified there.

The arguments to this scheduler are:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional):
See codebases scheduler argument.
fileIsImportant (optional)
See fileIsImportant scheduler argument.
change_filter (optional)
See change_filter scheduler argument.
onlyImportant (optional)
See onlyImportant scheduler argument.
reason (optional)
See reason scheduler argument.

The scheduler will wait for this many seconds before starting the build. If new changes are made during this interval, the timer will be restarted, so really the build will be started after a change and then after this many seconds of inactivity.

If treeStableTimer is None, then a separate build is started immediately for each Change.

categories (deprecated; use change_filter)
A list of categories of changes that this scheduler will respond to. If this is specified, then any non-matching changes are ignored.
branch (deprecated; use change_filter)

The scheduler will pay attention to this branch, ignoring Changes that occur on other branches. Setting branch equal to the special value of None means it should only pay attention to the default branch.


None is a keyword, not a string, so write None and not "None".


from buildbot.plugins import schedulers, util
quick = schedulers.SingleBranchScheduler(
            builderNames=["quick-linux", "quick-netbsd"])
full = schedulers.SingleBranchScheduler(
            builderNames=["full-linux", "full-netbsd", "full-OSX"])
c['schedulers'] = [quick, full]

In this example, the two quick builders are triggered 60 seconds after the tree has been changed. The full builds do not run quite so quickly (they wait 5 minutes), so hopefully if the quick builds fail due to a missing file or really simple typo, the developer can discover and fix the problem before the full builds are started. Both schedulers only pay attention to the default branch: any changes on other branches are ignored. Each scheduler triggers a different set of Builders, referenced by name.


The old names for this scheduler, buildbot.scheduler.Scheduler and buildbot.schedulers.basic.Scheduler, are deprecated in favor of using buildbot.plugins:

from buildbot.plugins import schedulers

However if you must use a fully qualified name, it is buildbot.schedulers.basic.SingleBranchScheduler.


This scheduler uses a tree-stable-timer like the default one, but uses a separate timer for each branch.

If treeStableTimer is not set, then this scheduler is indistinguishable from SingleBranchScheduler. If treeStableTimer is set, then a build is triggered for each set of Changes which arrive within the configured time, and match the filters.

The arguments to this scheduler are:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional):
See codebases scheduler argument.
fileIsImportant (optional)
See fileIsImportant scheduler argument.
change_filter (optional)
See change_filter scheduler argument.
onlyImportant (optional)
See onlyImportant scheduler argument.
reason (optional)
See reason scheduler argument.
The scheduler will wait for this many seconds before starting the build. If new changes are made on the same branch during this interval, the timer will be restarted.
branches (deprecated; use change_filter)
Changes on branches not specified on this list will be ignored.
categories (deprecated; use change_filter)
A list of categories of changes that this scheduler will respond to. If this is specified, then any non-matching changes are ignored.
Dependent Scheduler

It is common to wind up with one kind of build which should only be performed if the same source code was successfully handled by some other kind of build first. An example might be a packaging step: you might only want to produce .deb or RPM packages from a tree that was known to compile successfully and pass all unit tests. You could put the packaging step in the same Build as the compile and testing steps, but there might be other reasons to not do this (in particular you might have several Builders worth of compiles/tests, but only wish to do the packaging once). Another example is if you want to skip the full builds after a failing quick build of the same source code. Or, if one Build creates a product (like a compiled library) that is used by some other Builder, you’d want to make sure the consuming Build is run after the producing one.

You can use dependencies to express this relationship to the Buildbot. There is a special kind of scheduler named Dependent that will watch an upstream scheduler for builds to complete successfully (on all of its Builders). Each time that happens, the same source code (i.e. the same SourceStamp) will be used to start a new set of builds, on a different set of Builders. This downstream scheduler doesn’t pay attention to Changes at all. It only pays attention to the upstream scheduler.

If the build fails on any of the Builders in the upstream set, the downstream builds will not fire. Note that, for SourceStamps generated by a Dependent scheduler, the revision is None, meaning HEAD. If any changes are committed between the time the upstream scheduler begins its build and the time the dependent scheduler begins its build, then those changes will be included in the downstream build. See the Triggerable scheduler for a more flexible dependency mechanism that can avoid this problem.

The keyword arguments to this scheduler are:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional):
See codebases scheduler argument.
The upstream scheduler to watch. Note that this is an instance, not the name of the scheduler.


from buildbot.plugins import schedulers
tests = schedulers.SingleBranchScheduler(name="just-tests",
package = schedulers.Dependent(name="build-package",
                               upstream=tests, # <- no quotes!
                               builderNames=["make-tarball", "make-deb",
c['schedulers'] = [tests, package]
Periodic Scheduler

This simple scheduler just triggers a build every N seconds.

The arguments to this scheduler are:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional):
See codebases scheduler argument.
fileIsImportant (optional)
See fileIsImportant scheduler argument.
change_filter (optional)
See change_filter scheduler argument.
onlyImportant (optional)
See onlyImportant scheduler argument.
reason (optional)
See reason scheduler argument.
createAbsoluteSourceStamps (optional)
This option only has effect when using multiple codebases. When True, it uses the last seen revision for each codebase that does not have a change. When False (the default), codebases without changes will use the revision from the codebases argument.
onlyIfChanged (optional)
If this is True, then builds will not be scheduled at the designated time unless the specified branch has seen an important change since the previous build. By default this setting is False.
The time, in seconds, after which to start a build.


from buildbot.plugins import schedulers
nightly = schedulers.Periodic(name="daily",
c['schedulers'] = [nightly]

The scheduler in this example just runs the full solaris build once per day. Note that this scheduler only lets you control the time between builds, not the absolute time-of-day of each Build, so this could easily wind up an evening or every afternoon scheduler depending upon when it was first activated.

Nightly Scheduler

This is highly configurable periodic build scheduler, which triggers a build at particular times of day, week, month, or year. The configuration syntax is very similar to the well-known crontab format, in which you provide values for minute, hour, day, and month (some of which can be wildcards), and a build is triggered whenever the current time matches the given constraints. This can run a build every night, every morning, every weekend, alternate Thursdays, on your boss’s birthday, etc.

Pass some subset of minutehourdayOfMonthmonth, and dayOfWeek; each may be a single number or a list of valid values. The builds will be triggered whenever the current time matches these values. Wildcards are represented by a ‘*’ string. All fields default to a wildcard except ‘minute’, so with no fields this defaults to a build every hour, on the hour. The full list of parameters is:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional):
See codebases scheduler argument.
fileIsImportant (optional)
See fileIsImportant scheduler argument.
change_filter (optional)
See change_filter scheduler argument.
onlyImportant (optional)
See onlyImportant scheduler argument.
reason (optional)
See reason scheduler argument.
createAbsoluteSourceStamps (optional)
This option only has effect when using multiple codebases. When True, it uses the last seen revision for each codebase that does not have a change. When False (the default), codebases without changes will use the revision from the codebases argument.
onlyIfChanged (optional)
If this is True, then builds will not be scheduled at the designated time unless the change filter has accepted an important change since the previous build. The default of this value is False.
branch (optional)
(deprecated; use change_filter and codebases) The branch to build when the time comes, and the branch to filter for if change_filter is not specified. Remember that a value of None here means the default branch, and will not match other branches!
minute (optional)
The minute of the hour on which to start the build. This defaults to 0, meaning an hourly build.
hour (optional)
The hour of the day on which to start the build, in 24-hour notation. This defaults to *, meaning every hour.
dayOfMonth (optional)
The day of the month to start a build. This defaults to *, meaning every day.
month (optional)
The month in which to start the build, with January = 1. This defaults to *, meaning every month.
dayOfWeek (optional)
The day of the week to start a build, with Monday = 0. This defaults to *, meaning every day of the week.

For example, the following master.cfg clause will cause a build to be started every night at 3:00am:

from buildbot.plugins import schedulers
                       builderNames=['builder1', 'builder2'],
                       hour=3, minute=0))

This scheduler will perform a build each Monday morning at 6:23am and again at 8:23am, but only if someone has committed code in the interim:

                       dayOfWeek=0, hour=[6,8], minute=23,

The following runs a build every two hours, using Python’s range function:

        branch=None, # default branch
        hour=range(0, 24, 2)))

Finally, this example will run only on December 24th:

        branch=None, # default branch
        builderNames=['flying_circuits', 'radar'],
Try Schedulers

This scheduler allows developers to use the buildbot try command to trigger builds of code they have not yet committed. See try for complete details.

Two implementations are available: Try_Jobdir and Try_Userpass. The former monitors a job directory, specified by the jobdir parameter, while the latter listens for PB connections on a specific port, and authenticates against userport.

The buildmaster must have a scheduler instance in the config file’s schedulers list to receive try requests. This lets the administrator control who may initiate these trial builds, which branches are eligible for trial builds, and which Builders should be used for them.

The scheduler has various means to accept build requests. All of them enforce more security than the usual buildmaster ports do. Any source code being built can be used to compromise the worker accounts, but in general that code must be checked out from the VC repository first, so only people with commit privileges can get control of the workers. The usual force-build control channels can waste worker time but do not allow arbitrary commands to be executed by people who don’t have those commit privileges. However, the source code patch that is provided with the trial build does not have to go through the VC system first, so it is important to make sure these builds cannot be abused by a non-committer to acquire as much control over the workers as a committer has. Ideally, only developers who have commit access to the VC repository would be able to start trial builds, but unfortunately the buildmaster does not, in general, have access to VC system’s user list.

As a result, the try scheduler requires a bit more configuration. There are currently two ways to set this up:

jobdir (ssh)

This approach creates a command queue directory, called the jobdir, in the buildmaster’s working directory. The buildmaster admin sets the ownership and permissions of this directory to only grant write access to the desired set of developers, all of whom must have accounts on the machine. The buildbot try command creates a special file containing the source stamp information and drops it in the jobdir, just like a standard maildir. When the buildmaster notices the new file, it unpacks the information inside and starts the builds.

The config file entries used by ‘buildbot try’ either specify a local queuedir (for which write and mv are used) or a remote one (using scp and ssh).

The advantage of this scheme is that it is quite secure, the disadvantage is that it requires fiddling outside the buildmaster config (to set the permissions on the jobdir correctly). If the buildmaster machine happens to also house the VC repository, then it can be fairly easy to keep the VC userlist in sync with the trial-build userlist. If they are on different machines, this will be much more of a hassle. It may also involve granting developer accounts on a machine that would not otherwise require them.

To implement this, the worker invokes ssh -l username host buildbot tryserver ARGS, passing the patch contents over stdin. The arguments must include the inlet directory and the revision information.

user+password (PB)

In this approach, each developer gets a username/password pair, which are all listed in the buildmaster’s configuration file. When the developer runs buildbot try, their machine connects to the buildmaster via PB and authenticates themselves using that username and password, then sends a PB command to start the trial build.

The advantage of this scheme is that the entire configuration is performed inside the buildmaster’s config file. The disadvantages are that it is less secure (while the cred authentication system does not expose the password in plaintext over the wire, it does not offer most of the other security properties that SSH does). In addition, the buildmaster admin is responsible for maintaining the username/password list, adding and deleting entries as developers come and go.

For example, to set up the jobdir style of trial build, using a command queue directory of MASTERDIR/jobdir (and assuming that all your project developers were members of the developers unix group), you would first set up that directory:

mkdir -p MASTERDIR/jobdir MASTERDIR/jobdir/new MASTERDIR/jobdir/cur MASTERDIR/jobdir/tmp
chgrp developers MASTERDIR/jobdir MASTERDIR/jobdir/*
chmod g+rwx,o-rwx MASTERDIR/jobdir MASTERDIR/jobdir/*

and then use the following scheduler in the buildmaster’s config file:

from buildbot.plugins import schedulers
s = schedulers.Try_Jobdir(name="try1",
                          builderNames=["full-linux", "full-netbsd",
c['schedulers'] = [s]

Note that you must create the jobdir before telling the buildmaster to use this configuration, otherwise you will get an error. Also remember that the buildmaster must be able to read and write to the jobdir as well. Be sure to watch the twistd.log file (Logfiles) as you start using the jobdir, to make sure the buildmaster is happy with it.


Patches in the jobdir are encoded using netstrings, which place an arbitrary upper limit on patch size of 99999 bytes. If your submitted try jobs are rejected with BadJobfile, try increasing this limit with a snippet like this in your master.cfg:

from twisted.protocols.basic import NetstringReceiver
NetstringReceiver.MAX_LENGTH = 1000000

To use the username/password form of authentication, create a Try_Userpass instance instead. It takes the same builderNames argument as the Try_Jobdir form, but accepts an additional port argument (to specify the TCP port to listen on) and a userpass list of username/password pairs to accept. Remember to use good passwords for this: the security of the worker accounts depends upon it:

from buildbot.plugins import schedulers
s = schedulers.Try_Userpass(name="try2",
                            builderNames=["full-linux", "full-netbsd",
                            userpass=[("alice","pw1"), ("bob", "pw2")])
c['schedulers'] = [s]

Like most places in the buildbot, the port argument takes a strports specification. See twisted.application.strports for details.

Triggerable Scheduler

The Triggerable scheduler waits to be triggered by a Trigger step (see Triggering Schedulers) in another build. That step can optionally wait for the scheduler’s builds to complete. This provides two advantages over Dependent schedulers. First, the same scheduler can be triggered from multiple builds. Second, the ability to wait for Triggerable’s builds to complete provides a form of “subroutine call”, where one or more builds can “call” a scheduler to perform some work for them, perhaps on other workers. The Triggerable scheduler supports multiple codebases. The scheduler filters out all codebases from Trigger steps that are not configured in the scheduler.

The parameters are just the basics:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional):
See codebases scheduler argument.
reason (optional)
See reason scheduler argument.

This class is only useful in conjunction with the Trigger step. Here is a fully-worked example:

from buildbot.plugins import schedulers, util, steps

checkin = schedulers.SingleBranchScheduler(name="checkin",
nightly = schedulers.Nightly(name='nightly',
                             hour=3, minute=0)

mktarball = schedulers.Triggerable(name="mktarball", builderNames=["mktarball"])
build = schedulers.Triggerable(name="build-all-platforms",
test = schedulers.Triggerable(name="distributed-test",
package = schedulers.Triggerable(name="package-all-platforms",
c['schedulers'] = [mktarball, checkin, nightly, build, test, package]

# on checkin, make a tarball, build it, and test it
checkin_factory = util.BuildFactory()

# and every night, make a tarball, build it, and package it
nightly_factory = util.BuildFactory()
NightlyTriggerable Scheduler
class buildbot.schedulers.timed.NightlyTriggerable

The NightlyTriggerable scheduler is a mix of the Nightly and Triggerable schedulers. This scheduler triggers builds at a particular time of day, week, or year, exactly as the Nightly scheduler. However, the source stamp set that is used that provided by the last Trigger step that targeted this scheduler.

The parameters are just the basics:

See name scheduler argument.
See builderNames scheduler argument.
properties (optional)
See properties scheduler argument.
codebases (optional)
See codebases scheduler argument.
reason (optional)
See reason scheduler argument.
minute (optional)
See Nightly.
hour (optional)
See Nightly.
dayOfMonth (optional)
See Nightly.
month (optional)
See Nightly.
dayOfWeek (optional)
See Nightly.

This class is only useful in conjunction with the Trigger step. Note that waitForFinish is ignored by Trigger steps targeting this scheduler.

Here is a fully-worked example:

from buildbot.plugins import schedulers, util, steps

checkin = schedulers.SingleBranchScheduler(name="checkin",
nightly = schedulers.NightlyTriggerable(name='nightly',
                                        hour=3, minute=0)
c['schedulers'] = [checkin, nightly]

# on checkin, run tests
checkin_factory = util.BuildFactory([

# and every night, package the latest successful build
nightly_factory = util.BuildFactory([
    steps.ShellCommand(command=['make', 'package'])
ForceScheduler Scheduler

The ForceScheduler scheduler is the way you can configure a force build form in the web UI.

In the /#/builders/:builderid web page, you will see, on the top right of the page, one button for each ForceScheduler scheduler that was configured for this builder. If you click on that button, a dialog will let you choose various parameters for requesting a new build.

The Buildbot framework allows you to customize exactly how the build form looks, which builders have a force build form (it might not make sense to force build every builder), and who is allowed to force builds on which builders.

How you do so is by configuring a ForceScheduler, and add it into the list schedulers.

The scheduler takes the following parameters:

See name scheduler argument.
List of builders where the force button should appear. See builderNames scheduler argument.


parameter allowing the user to specify the reason for the build. The default value is a string parameter with a default value “force build”.


A string that will be used to create the build reason for the forced build. This string can contain the placeholders %(owner)s and %(reason)s, which represents the value typed into the reason field.


parameter specifying the username associated with the build (aka owner). The default value is a username parameter.


A list of strings or CodebaseParameter specifying the codebases that should be presented. The default is a single codebase with no name (i.e. codebases=[‘’]).


A list of parameters, one for each property. These can be arbitrary parameters, where the parameter’s name is taken as the property name, or AnyPropertyParameter, which allows the web user to specify the property name. The default value is an empty list.


The name of the “submit” button on the resulting force-build form. This defaults to the name of scheduler.

An example may be better than long explanation. What you need in your config file is something like:

from buildbot.plugins import schedulers, util

sch = schedulers.ForceScheduler(
    label="My nice Force form",

            label="Main repository",
            # will generate a combo box
                choices=["master", "hest"],

            # will generate nothing in the form, but revision, repository,
            # and project are needed by buildbot scheduling system so we
            # need to pass a value ("")
            revision=util.FixedParameter(name="revision", default=""),
            repository=util.FixedParameter(name="repository", default=""),
            project=util.FixedParameter(name="project", default=""),

    # will generate a text input
                                required=True, size=80),

    # in case you don't require authentication this will display
    # input for user to type his name
    username=util.UserNameParameter(label="your name:",
    # A completely customized property list.  The name of the
    # property is the name of the parameter
        util.NestedParameter(name="options", label="Build Options", layout="vertical", fields=[
                                 label="optionally give a public Git pull url:",
                                 default="", size=80),
                                  label="force a make clean",

This will result in the following UI:

Force Form ResultAuthorization

The force scheduler uses the web interface’s authorization framework to determine which user has the right to force which build. Here is an example of code on how you can define which user has which right:

user_mapping = {
    re.compile("project1-builder"): ["project1-maintainer", "john"] ,
    re.compile("project2-builder"): ["project2-maintainer", "jack"],
    re.compile(".*"): ["root"]
def force_auth(user,  status):
    global user_mapping
    for r,users in user_mapping.items():
        if r.match(
            if user in users:
                    return True
    return False

# use authz_cfg in your WebStatus setup
    forceBuild = force_auth,

ForceScheduler Parameters

Most of the arguments to ForceScheduler are “parameters”. Several classes of parameters are available, each describing a different kind of input from a force-build form.

All parameter types have a few common arguments:

name (required)

The name of the parameter. For properties, this will correspond to the name of the property that your parameter will set. The name is also used internally as the identifier for in the HTML form.

label (optional; default is same as name)

The label of the parameter. This is what is displayed to the user.

tablabel (optional; default is same as label)

The label of the tab if this parameter is included into a tab layout NestedParameter. This is what is displayed to the user.

default (optional; default: “”)

The default value for the parameter, that is used if there is no user input.

required (optional; default: False)

If this is true, then an error will be shown to user if there is no input in this field

maxsize (optional; default: None)

The maximum size of a field (in bytes). Buildbot will ensure the field sent by the user is not too large.

autopopulate (optional; default: None)

If not None, autopopulate is a dictionary which describes how other parameters are updated if this one changes. This is useful for when you have lots of parameters, and defaults depends on e.g. the branch. This is implemented generically, and all parameters can update others. Beware of infinite loops!

buttonName="Start Custom Build",
codebases = [util.CodebaseParameter(
    codebase='', project=None,
        choices=["master", "dev"],
        'master': {
            'build_name': 'build for master branch',
        'dev': {
            'build_name': 'build for dev branch',
        label="Name of the Build release.",
        default="")]))  # this parameter will be auto populated when user chooses branch

The parameter types are:


NestedParameter(name="options", label="Build options" layout="vertical", fields=[...]),

This parameter type is a special parameter which contains other parameters. This can be used to group a set of parameters together, and define the layout of your form. You can recursively include NestedParameter into NestedParameter, to build very complex UI.

It adds the following arguments:

layout (optional, default: “vertical”)

The layout defines how the fields are placed in the form.

The layouts implemented in the standard web application are:

  • simple: fields are displayed one by one without alignment.

    They take the horizontal space that they need.

  • vertical: all fields are displayed vertically, aligned in columns (as per the columnattribute of the NestedParameter)

  • tabs: Each field gets its own tab.

    This can be used to declare complex build forms which won’t fit into one screen. The children fields are usually other NestedParameters with vertical layout.

columns (optional, accepted values are 1,2,3,4)

The number of columns to use for a vertical layout. If omitted, it is set to 1 unless there are more than 3 visible child fields in which case it is set to 2.


FixedParameter(name="branch", default="trunk"),

This parameter type will not be shown on the web form, and always generate a property with its default value.


    label="optionally give a public Git pull url:",
    default="", size=80)

This parameter type will show a single-line text-entry box, and allow the user to enter an arbitrary string. It adds the following arguments:

regex (optional)

A string that will be compiled as a regex, and used to validate the input of this parameter.

size (optional; default: 10)

The width of the input field (in characters).


    label="comments to be displayed to the user of the built binary",
    default="This is a development build", cols=60, rows=5)

This parameter type is similar to StringParameter, except that it is represented in the HTML form as a textarea, allowing multi-line input. It adds the StringParameter arguments, this type allows:

cols (optional; default: 80)

The number of columns the textarea will have.

rows (optional; default: 20)

The number of rows the textarea will have

This class could be subclassed in order to have more customization e.g.

  • developer could send a list of Git branches to pull from
  • developer could send a list of Gerrit changes to cherry-pick,
  • developer could send a shell script to amend the build.

Beware of security issues anyway.


    label="debug level (1-10)", default=2)

This parameter type accepts an integer value using a text-entry box.


    label="force a make clean", default=False)

This type represents a boolean value. It will be presented as a checkbox.


UserNameParameter(label="your name:", size=80)

This parameter type accepts a username. If authentication is active, it will use the authenticated user instead of displaying a text-entry box.

size (optional; default: 10)
The width of the input field (in characters).
need_email (optional; default True)
If true, require a full email address rather than arbitrary text.


    choices=["main","devel"], default="main")

This parameter type lets the user choose between several choices (e.g the list of branches you are supporting, or the test campaign to run). If multiple is false, then its result is a string - one of the choices. If multiple is true, then the result is a list of strings from the choices.

Note that for some use cases, the choices need to be generated dynamically. This can be done via subclassing and overriding the ‘getChoices’ member function. An example of this is provided by the source for the InheritBuildParameter class.

Its arguments, in addition to the common options, are:


The list of available choices.

strict (optional; default: True)

If true, verify that the user’s input is from the list. Note that this only affects the validation of the form request; even if this argument is False, there is no HTML form component available to enter an arbitrary value.


If true, then the user may select multiple choices.


                      label="smoke test campaign to run",
                      choices=["test_builder1", "test_builder2",

# .. and later base the schedulers to trigger off this property:

# triggers the tests depending on the property forced_test
builder1.factory.addStep(Trigger(name="Trigger tests",



This is a parameter group to specify a sourcestamp for a given codebase.


The name of the codebase.

branch (optional; default: StringParameter)

parameter specifying the branch to build. The default value is a string parameter.

revision (optional; default: StringParameter)

parameter specifying the revision to build. The default value is a string parameter.

repository (optional; default: StringParameter)

parameter specifying the repository for the build. The default value is a string parameter.

project (optional; default: StringParameter)

parameter specifying the project for the build. The default value is a string parameter.

patch (optional; default: None)

PatchParameter specifying that the user can upload a patch for this codebase.


This parameter allows the user to upload a file to a build. The user can either write some text to a text area, or select a file from the browser. Note that the file is then stored inside a property, so a maxsizeof 10 megabytes has been set. You can still override that maxsize if you wish.


This parameter allows the user to specify a patch to be applied at the source step. The patch is stored within the sourcestamp, and associated to a codebase. That is why PatchParameter must be set inside a CodebaseParameter.

PatchParameter is actually a NestedParameter composed of following fields:

IntParameter('level', default=1),
StringParameter('author', default=""),
StringParameter('comment', default=""),
StringParameter('subdir', default=".")

You can customize any of these fields by overwriting their field name e.g:

c['schedulers'] = [
        codebases=[util.CodebaseParameter("foo", patch=util.PatchParameter(
            body=FileParameter('body', maxsize=10000)))],  # override the maximum size of a patch to 10k instead of 10M



InheritBuildParameter is not yet ported to data API, and cannot be used with buildbot nine yet(bug #3521).

This is a special parameter for inheriting force build properties from another build. The user is presented with a list of compatible builds from which to choose, and all forced-build parameters from the selected build are copied into the new build. The new parameter is:


A function to find compatible builds in the build history. This function is given the master Status instance as first argument, and the current builder name as second argument, or None when forcing all builds.


def get_compatible_builds(status, builder):
    if builder is None: # this is the case for force_build_all
        return ["cannot generate build list here"]
    # find all successful builds in builder1 and builder2
    builds = []
    for builder in ["builder1","builder2"]:
        builder_status = status.getBuilder(builder)
        for num in range(1,40): # 40 last builds
            b = builder_status.getBuild(-num)
            if not b:
            if b.getResults() == FAILURE:
    return builds

# ...

sched = Scheduler(...,
            label="promote a build for merge",
            required = True),



WorkerChoiceParameter is not yet ported to data API, and cannot be used with buildbot nine yet(bug #3521).

This parameter allows a scheduler to require that a build is assigned to the chosen worker. The choice is assigned to the workername property for the build. The enforceChosenWorker functor must be assigned to the canStartBuild parameter for the Builder.


from buildbot.plugins import util

# schedulers:
    # ...

# builders:
    # ...


This parameter type can only be used in properties, and allows the user to specify both the property name and value in the web form.

This Parameter is here to reimplement old Buildbot behavior, and should be avoided. Stricter parameter name and type should be preferred.

2.5.6. Workers

The workers configuration key specifies a list of known workers. In the common case, each worker is defined by an instance of the buildbot.worker.Worker class. It represents a standard, manually started machine that will try to connect to the Buildbot master as a worker. Buildbot also supports “on-demand”, or latent, workers, which allow Buildbot to dynamically start and stop worker instances. Defining Workers

Worker instance is created with a workername and a workerpassword. These are the same two values that need to be provided to the worker administrator when they create the worker.

The workername must be unique, of course. The password exists to prevent evildoers from interfering with the Buildbot by inserting their own (broken) workers into the system and thus displacing the real ones.

Workers with an unrecognized workername or a non-matching password will be rejected when they attempt to connect, and a message describing the problem will be written to the log file (see Logfiles).

A configuration for two workers would look like:

from buildbot.plugins import worker
c['workers'] = [
    worker.Worker('bot-solaris', 'solarispasswd'),
    worker.Worker('bot-bsd', 'bsdpasswd'),
] Worker Options

Worker objects can also be created with an optional properties argument, a dictionary specifying properties that will be available to any builds performed on this worker. For example:

c['workers'] = [
    worker.Worker('bot-solaris', 'solarispasswd',
                  properties={ 'os':'solaris' }),
Limiting Concurrency

The Worker constructor can also take an optional max_builds parameter to limit the number of builds that it will execute simultaneously:

c['workers'] = [
    worker.Worker('bot-linux', 'linuxpassword',


In Worker For Builders concept only one build from the same builder would run on the worker.

Master-Worker TCP Keepalive

By default, the buildmaster sends a simple, non-blocking message to each worker every hour. These keepalives ensure that traffic is flowing over the underlying TCP connection, allowing the system’s network stack to detect any problems before a build is started.

The interval can be modified by specifying the interval in seconds using the keepalive_intervalparameter of Worker (defaults to 3600):

c['workers'] = [
    worker.Worker('bot-linux', 'linuxpasswd',

The interval can be set to None to disable this functionality altogether.

When Workers Go Missing

Sometimes, the workers go away. One very common reason for this is when the worker process is started once (manually) and left running, but then later the machine reboots and the process is not automatically restarted.

If you’d like to have the administrator of the worker (or other people) be notified by email when the worker has been missing for too long, just add the notify_on_missing= argument to the Workerdefinition. This value can be a single email address, or a list of addresses:

c['workers'] = [
    worker.Worker('bot-solaris', 'solarispasswd',

By default, this will send email when the worker has been disconnected for more than one hour. Only one email per connection-loss event will be sent. To change the timeout, use missing_timeout= and give it a number of seconds (the default is 3600).

You can have the buildmaster send email to multiple recipients: just provide a list of addresses instead of a single one:

c['workers'] = [
    worker.Worker('bot-solaris', 'solarispasswd',
                  missing_timeout=300)  # notify after 5 minutes

The email sent this way will use a MailNotifier (see MailNotifier) status target, if one is configured. This provides a way for you to control the from address of the email, as well as the relayhost (aka smarthost) to use as an SMTP server. If no MailNotifier is configured on this buildmaster, the worker-missing emails will be sent using a default configuration.

Note that if you want to have a MailNotifier for worker-missing emails but not for regular build emails, just create one with builders=[], as follows:

from buildbot.plugins import status, worker
m = status.MailNotifier(fromaddr='buildbot@localhost', builders=[],

c['workers'] = [
        worker.Worker('bot-solaris', 'solarispasswd',
Workers States

There are some times when a worker misbehaves because of issues with its configuration. In those cases, you may want to pause the worker, or maybe completely shut it down.

There are three actions that you may take (in the worker’s web page Actions dialog)

  • Pause: If a worker is paused, it won’t accept new builds. The action of pausing a worker will not affect any build ongoing.
  • Graceful Shutdown: If a worker is in graceful shutdown mode, it won’t accept new builds, but will finish the current builds. When all of its build are finished, the buildbot-worker process will terminate.
  • Force Shutdown: If a worker is in force shutdown mode, it will terminate immediately, and the build he was currently doing will be put to retry state.

Those actions will put the worker in two states

  • paused: the worker is paused if it is connected but doesn’t accept new builds.
  • graceful: the worker is graceful if it doesn’t accept new builds, and will shutdown when builds are finished.

A worker might be put to paused state automatically if buildbot detects a misbehavior. This is called the quarantine timer.

Quarantine timer is an exponential back-off mechanism for workers. This avoids a misbehaving worker to eat the build queue by quickly finishing builds in EXCEPTION state. When misbehavior is detected, the timer will pause the worker for 10 second, and then that time will double at each misbehavior detection, until the worker finishes a build.

The first case of misbehavior is for a latent worker to not start properly. The second case of misbehavior is for a build to end with an EXCEPTION status.

Worker states are stored in the database, can be queried via REST API and visible in the UI’s workers page. Local Workers

For smaller setups, you may want to just run the workers on the same machine as the master. To simplify the maintenance, you may even want to run them in the same process.

This is what LocalWorker is for. Instead of configuring a worker.Worker, you have to configure a worker.LocalWorker. As the worker is running on the same process, password is not necessary. You can run as many local workers as long as your machine CPU and memory is allowing.

A configuration for two workers would look like:

from buildbot.plugins import worker
c['workers'] = [

In order to use local workers you need to have buildbot-worker package installed. Latent Workers

The standard Buildbot model has workers started manually. The previous section described how to configure the master for this approach.

Another approach is to let the Buildbot master start workers when builds are ready, on-demand. Thanks to services such as Amazon Web Services’ Elastic Compute Cloud (“AWS EC2”), this is relatively easy to set up, and can be very useful for some situations.

The workers that are started on-demand are called “latent” workers. You can find the list of Supported Latent Workers below.

Common Options

The following options are available for all latent workers.

This option allows you to specify how long a latent worker should wait after a build for another build before it shuts down. It defaults to 10 minutes. If this is set to 0 then the worker will be shut down immediately. If it is less than 0 it will never automatically shutdown.
Supported Latent Workers

As of time of writing, Buildbot supports the following latent workers:

Amazon Web Services Elastic Compute Cloud (“AWS EC2”)

class buildbot.worker.ec2.EC2LatentWorker

EC2 is a web service that allows you to start virtual machines in an Amazon data center. Please see their website for details, including costs. Using the AWS EC2 latent workers involves getting an EC2 account with AWS and setting up payment; customizing one or more EC2 machine images (“AMIs”) on your desired operating system(s) and publishing them (privately if needed); and configuring the buildbot master to know how to start your customized images for “substantiating” your latent workers.

This document will guide you through setup of a AWS EC2 latent worker:

Get an AWS EC2 Account

To start off, to use the AWS EC2 latent worker, you need to get an AWS developer account and sign up for EC2. Although Amazon often changes this process, these instructions should help you get started:

  1. Go to and click to “Sign Up Now” for an AWS account.
  2. Once you are logged into your account, you need to sign up for EC2. Instructions for how to do this have changed over time because Amazon changes their website, so the best advice is to hunt for it. After signing up for EC2, it may say it wants you to upload an x.509 cert. You will need this to create images (see below) but it is not technically necessary for the buildbot master configuration.
  3. You must enter a valid credit card before you will be able to use EC2. Do that under ‘Payment Method’.
  4. Make sure you’re signed up for EC2 by going to Your Account ‣ Account Activity and verifying EC2 is listed.

Create an AMI

Now you need to create an AMI and configure the master. You may need to run through this cycle a few times to get it working, but these instructions should get you started.

Creating an AMI is out of the scope of this document. The EC2 Getting Started Guide is a good resource for this task. Here are a few additional hints.

  • When an instance of the image starts, it needs to automatically start a buildbot worker that connects to your master (to create a buildbot worker, Creating a worker; to make a daemon, Launching the daemons).
  • You may want to make an instance of the buildbot worker, configure it as a standard worker in the master (i.e., not as a latent worker), and test and debug it that way before you turn it into an AMI and convert to a latent worker in the master.
  • In order to avoid extra costs in case of master failure, you should configure the worker of the AMI with maxretries option (see Worker Options) Also see example systemd unit file example

Configure the Master with an EC2LatentWorker

Now let’s assume you have an AMI that should work with the EC2LatentWorker. It’s now time to set up your buildbot master configuration.

You will need some information from your AWS account: the Access Key Id and the Secret Access Key. If you’ve built the AMI yourself, you probably already are familiar with these values. If you have not, and someone has given you access to an AMI, these hints may help you find the necessary values:

  • While logged into your AWS account, find the “Access Identifiers” link (either on the left, or via Your Account ‣ Access Identifiers.
  • On the page, you’ll see alphanumeric values for “Your Access Key Id:” and “Your Secret Access Key:”. Make a note of these. Later on, we’ll call the first one your identifier and the second one your secret_identifier.

When creating an EC2LatentWorker in the buildbot master configuration, the first three arguments are required. The name and password are the first two arguments, and work the same as with normal workers. The next argument specifies the type of the EC2 virtual machine (available options as of this writing include m1.smallm1.largem1.xlargec1.medium, and c1.xlarge; see the EC2 documentation for descriptions of these machines).

Here is the simplest example of configuring an EC2 latent worker. It specifies all necessary remaining values explicitly in the instantiation.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

The ami argument specifies the AMI that the master should start. The identifier argument specifies the AWS Access Key Id, and the secret_identifier specifies the AWS Secret Access Key. Both the AMI and the account information can be specified in alternate ways.


Whoever has your identifier and secret_identifier values can request AWS work charged to your account, so these values need to be carefully protected. Another way to specify these access keys is to put them in a separate file. Buildbot supports the standard AWS credentials file. You can then make the access privileges stricter for this separate file, and potentially let more people read your main configuration file. If your master is running in EC2, you can also use IAM roles for EC2 to delegate permissions.

keypair_name and security_name allow you to specify different names for these AWS EC2 values.

You can make an .aws directory in the home folder of the user running the buildbot master. In that directory, create a file called credentials. The format of the file should be as follows, replacing identifier and secret_identifier with the credentials obtained before.

aws_access_key_id = identifier
aws_secret_access_key = secret_identifier

If you are using IAM roles, no config file is required. Then you can instantiate the worker as follows.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

Previous examples used a particular AMI. If the Buildbot master will be deployed in a process-controlled environment, it may be convenient to specify the AMI more flexibly. Rather than specifying an individual AMI, specify one or two AMI filters.

In all cases, the AMI that sorts last by its location (the S3 bucket and manifest name) will be preferred.

One available filter is to specify the acceptable AMI owners, by AWS account number (the 12 digit number, usually rendered in AWS with hyphens like “1234-5678-9012”, should be entered as in integer).

from buildbot.plugins import worker
bot1 = worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

The other available filter is to provide a regular expression string that will be matched against each AMI’s location (the S3 bucket and manifest name).

from buildbot.plugins import worker
bot1 = worker.EC2LatentWorker(
        'bot1', 'sekrit', 'm1.large',

The regular expression can specify a group, which will be preferred for the sorting. Only the first group is used; subsequent groups are ignored.

from buildbot.plugins import worker
bot1 = worker.EC2LatentWorker(
    'bot1', 'sekrit', 'm1.large',

If the group can be cast to an integer, it will be. This allows 10 to sort after 1, for instance.

from buildbot.plugins import worker
bot1 = worker.EC2LatentWorker(
        'bot1', 'sekrit', 'm1.large',

In addition to using the password as a handshake between the master and the worker, you may want to use a firewall to assert that only machines from a specific IP can connect as workers. This is possible with AWS EC2 by using the Elastic IP feature. To configure, generate a Elastic IP in AWS, and then specify it in your configuration using the elastic_ip argument.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

One other way to configure a worker is by settings AWS tags. They can for example be used to have a more restrictive security IAM policy. To get Buildbot to tag the latent worker specify the tag keys and values in your configuration using the tags argument.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',
                           tags={'SomeTag': 'foo'})

If the worker needs access to additional AWS resources, you can also enable your workers to access them via an EC2 instance profile. To use this capability, you must first create an instance profile separately in AWS. Then specify its name on EC2LatentWorker via instance_profile_name.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

You may also supply your own boto3.Session object to allow for more flexible session options (ex. cross-account) To use this capability, you must first create a boto3.Session object. Then provide it to EC2LatentWorker via session argument.

import boto3
from buildbot.plugins import worker

session = boto3.session.Session()
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

The EC2LatentWorker supports all other configuration from the standard Worker. The missing_timeoutand notify_on_missing specify how long to wait for an EC2 instance to attach before considering the attempt to have failed, and email addresses to alert, respectively. missing_timeout defaults to 20 minutes.


If you want to attach existing volumes to an ec2 latent worker, use the volumes attribute. This mechanism can be valuable if you want to maintain state on a conceptual worker across multiple start/terminate sequences. volumes expects a list of (volume_id, mount_point) tuples to attempt attaching when your instance has been created.

If you want to attach new ephemeral volumes, use the the block_device_map attribute. This follows the AWS API syntax, essentially acting as a passthrough. The only distinction is that the volumes default to deleting on termination to avoid leaking volume resources when workers are terminated. See boto documentation for further details.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',
                           block_device_map= [
                             "DeviceName": "/dev/xvdb",
                             "Ebs" : {
                                "VolumeType": "io1",
                                "Iops": 1000,
                                "VolumeSize": 100

VPC Support

If you are managing workers within a VPC, your worker configuration must be modified from above. You must specify the id of the subnet where you want your worker placed. You must also specify security groups created within your VPC as opposed to classic EC2 security groups. This can be done by passing the ids of the vpc security groups. Note, when using a VPC, you can not specify classic EC2 security groups (as specified by security_name).

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',

Spot instances

If you would prefer to use spot instances for running your builds, you can accomplish that by passing in a True value to the spot_instance parameter to the EC2LatentWorker constructor. Additionally, you may want to specify max_spot_price and price_multiplier in order to limit your builds’ budget consumption.

from buildbot.plugins import worker
c['workers'] = [
    worker.EC2LatentWorker('bot1', 'sekrit', 'm1.large',
                           'ami-12345', region='us-west-2',
                           placement='b', spot_instance=True,

This example would attempt to create a m1.large spot instance in the us-west-2b region costing no more than $0.09/hour. The spot prices for ‘Linux/UNIX’ spot instances in that region over the last 24 hours will be averaged and multiplied by the price_multiplier parameter, then a spot request will be sent to Amazon with the above details. If the multiple exceeds the max_spot_price, the bid price will be the max_spot_price.

Either max_spot_price or price_multiplier, but not both, may be None. If price_multiplier is None, then no historical price information is retrieved; the bid price is simply the specified max_spot_price. If the max_spot_price is None, then the multiple of the historical average spot prices is used as the bid price with no limit.


class buildbot.worker.libvirt.LibVirtWorker

libvirt is a virtualization API for interacting with the virtualization capabilities of recent versions of Linux and other OSes. It is LGPL and comes with a stable C API, and Python bindings.

This means we now have an API which when tied to buildbot allows us to have workers that run under Xen, QEMU, KVM, LXC, OpenVZ, User Mode Linux, VirtualBox and VMWare.

The libvirt code in Buildbot was developed against libvirt 0.7.5 on Ubuntu Lucid. It is used with KVM to test Python code on VMs, but obviously isn’t limited to that. Each build is run on a new VM, images are temporary and thrown away after each build.

This document will guide you through setup of a libvirt latent worker:

Setting up libvirt

We won’t show you how to set up libvirt as it is quite different on each platform, but there are a few things you should keep in mind.

  • If you are using the system libvirt (libvirt and buildbot master are on same server), your buildbot master user will need to be in the libvirtd group.
  • If libvirt and buildbot master are on different servers, the user connecting to libvirt over ssh will need to be in the libvirtd group. Also need to setup authorization via ssh-keys (without password prompt).
  • If you are using KVM, your buildbot master user will need to be in the KVM group.
  • You need to think carefully about your virtual network first. Will NAT be enough? What IP will my VMs need to connect to for connecting to the master?

Configuring your base image

You need to create a base image for your builds that has everything needed to build your software. You need to configure the base image with a buildbot worker that is configured to connect to the master on boot.

Because this image may need updating a lot, we strongly suggest scripting its creation.

If you want to have multiple workers using the same base image it can be annoying to duplicate the image just to change the buildbot credentials. One option is to use libvirt’s DHCP server to allocate an identity to the worker: DHCP sets a hostname, and the worker takes its identity from that.

Doing all this is really beyond the scope of the manual, but there is a vmbuilder script and a network.xml file to create such a DHCP server in master/contrib/ (Contrib Scripts) that should get you started:

sudo apt-get install ubuntu-vm-builder
sudo contrib/libvirt/vmbuilder

Should create an ubuntu/ folder with a suitable image in it.

virsh net-define contrib/libvirt/network.xml
virsh net-start buildbot-network

Should set up a KVM compatible libvirt network for your buildbot VM’s to run on.

Configuring your Master

If you want to add a simple on demand VM to your setup, you only need the following. We set the username to minion1, the password to sekrit. The base image is called base_image and a copy of it will be made for the duration of the VM’s life. That copy will be thrown away every time a build is complete.

from buildbot.plugins import worker, util
c['workers'] = [
    worker.LibVirtWorker('minion1', 'sekrit',

You can use virt-manager to define minion1 with the correct hardware. If you don’t, buildbot won’t be able to find a VM to start.

LibVirtWorker accepts the following arguments:

Both a buildbot username and the name of the virtual machine.
A password for the buildbot to login to the master with.
Connection instance wrapping connection to libvirt.
The path to a libvirt disk image, normally in qcow2 format when using KVM.
If given a base image, buildbot will clone it every time it starts a VM. This means you always have a clean environment to do your build in.
If a VM isn’t predefined in virt-manager, then you can instead provide XML like that used with virsh define. The VM will be created automatically when needed, and destroyed when not needed any longer.


The hd_image and base_image must be on same machine with buildbot master.

Configuring Master to use libvirt on remote server

If you want to use libvirt on remote server configure remote libvirt server and buildbot server following way.

  1. Define user to connect to remote machine using ssh. Configure connection of such user to remote libvirt server (see without password prompt.
  2. Add user to libvirtd group on remote libvirt server sudo usermod -G libvirtd -a <user>.

Configure remote libvirt server:

  1. Create virtual machine for buildbot and configure it.
  2. Change virtual machine image file to new name, which will be used as temporary image and deleted after virtual machine stops. Execute command sudo virsh edit <VM name>. In xml file locate devices/disk/source and change file path to new name. The file must not be exists, it will create via hook script.
  3. Add hook script to /etc/libvirt/hooks/qemu to recreate VM image each start:

# Script /etc/libvirt/hooks/qemu
# Don't forget to execute service libvirt-bin restart
# Also see

# This script make clean VM for each start using base image

import os
import subprocess
import sys

images_path = '/var/lib/libvirt/images/'

# build-vm - VM name in virsh list --all
# vm_base_image.qcow2 - base image file name, must exist in path /var/lib/libvirt/images/
# vm_temp_image.qcow2 - temporary image. Must not exist in path /var/lib/libvirt/images/, but defined in VM config file
domains = {
    'build-vm' : ['vm_base_image.qcow2', 'vm_temp_image.qcow2'],

def delete_image_clone(vir_domain):
    if vir_domain in domains:
             domain = domains[vir_domain]
             os.remove(images_path + domain[1])

def create_image_clone(vir_domain):
    if vir_domain in domains:
             domain = domains[vir_domain]
             cmd = ['/usr/bin/qemu-img', 'create', '-b', images_path + domain[0], '-f', 'qcow2', images_path + domain[1]]

if __name__ == "__main__":
    vir_domain, action = sys.argv[1:3]

    if action in ["prepare"]:

    if action in ["release"]:

Configure buildbot server:

  1. On buildbot server in virtual environment install libvirt-python package: pip install libvirt-python
  2. Create worker using remote ssh connection.
from buildbot.plugins import worker, util
c['workers'] = [
    worker.LibVirtWorker('minion1', 'sekrit',
                         util.Connection("qemu+ssh://<user>@<ip address or DNS name>:<port>/session"),


class buildbot.worker.openstack.OpenStackLatentWorker

OpenStack is a series of interconnected components that facilitates managing compute, storage, and network resources in a data center. It is available under the Apache License and has a REST interface along with a Python client.

This document will guide you through setup of an OpenStack latent worker:

Install dependencies

OpenStackLatentWorker requires python-novaclient to work, you can install it with pip install python-novaclient.

Get an Account in an OpenStack cloud

Setting up OpenStack is outside the domain of this document. There are four account details necessary for the Buildbot master to interact with your OpenStack cloud: username, password, a tenant name, and the auth URL to use.

Create an Image

OpenStack supports a large number of image formats. OpenStack maintains a short list of prebuilt images; if the desired image is not listed, The OpenStack Compute Administration Manual is a good resource for creating new images. You need to configure the image with a buildbot worker to connect to the master on boot.

Configure the Master with an OpenStackLatentWorker

With the configured image in hand, it is time to configure the buildbot master to create OpenStack instances of it. You will need the aforementioned account details. These are the same details set in either environment variables or passed as options to an OpenStack client.

OpenStackLatentWorker accepts the following arguments:

The worker name.
A password for the worker to login to the master with.
The flavor ID to use for the instance.
A string containing the image UUID to use for the instance. A callable may instead be passed. It will be passed the list of available images and must return the image to use.






The OpenStack authentication needed to create and delete instances. These are the same as the environment variables with uppercase names of the arguments.

A list of dictionaries. Each dictionary specifies a block device to set up during instance creation. The values support using properties from the build and will be rendered when the instance is started.

Supported keys

(required): The image, snapshot, or volume UUID.
(optional): Size of the block device in GiB. If not specified, the minimum size in GiB to contain the source will be calculated and used.
(optional): defaults to vda. The name of the device in the instance; e.g. vda or xda.
(optional): defaults to image. The origin of the block device. Valid values are imagesnapshot, or volume.
(optional): defaults to volume. Destination of block device: volume or local.
(optional): defaults to True. Controls if the block device will be deleted when the instance terminates.
(optional): defaults to 0. Integer used for boot order.
A dictionary of string key-value pairs to pass to the instance. These will be available under the metadata key from the metadata service.
(optional) A dict that will be appended to the arguments when creating a VM. Buildbot uses the OpenStack Nova version 2 API by default (see client_version).
(optional) A string containing the Nova client version to use. Defaults to 2. Supports using 2.X, where X is a micro-version. Use 1.1 for the previous, deprecated, version. If using 1.1, note that an older version of novaclient will be needed so it won’t switch to using 2.
(optional) A string specifying region where to instantiate the worker.

Here is the simplest example of configuring an OpenStack latent worker.

from buildbot.plugins import worker
c['workers'] = [
    worker.OpenStackLatentWorker('bot2', 'sekrit',
                flavor=1, image='8ac9d4a4-5e03-48b0-acde-77a0345a9ab1',
                os_username='user', os_password='password',

The image argument also supports being given a callable. The callable will be passed the list of available images and must return the image to use. The invocation happens in a separate thread to prevent blocking the build master when interacting with OpenStack.

from buildbot.plugins import worker

def find_image(images):
    # Sort oldest to newest.
    def key_fn(x):
        return x.created

    candidate_images = sorted(images, key=key_fn)
    # Return the oldest candidate image.
    return candidate_images[0]

c['workers'] = [
    worker.OpenStackLatentWorker('bot2', 'sekrit',
                flavor=1, image=find_image,
                os_username='user', os_password='password',

The block_devices argument is minimally manipulated to provide some defaults and passed directly to novaclient. The simplest example is an image that is converted to a volume and the instance boots from that volume. When the instance is destroyed, the volume will be terminated as well.

from buildbot.plugins import worker
c['workers'] = [
    worker.OpenStackLatentWorker('bot2', 'sekrit',
                flavor=1, image='8ac9d4a4-5e03-48b0-acde-77a0345a9ab1',
                os_username='user', os_password='password',
                    {'uuid': '3f0b8868-67e7-4a5b-b685-2824709bd486',
                    'volume_size': 10}])

The nova_args can be used to specify additional arguments for the novaclient. For example network mappings, which is required if your OpenStack tenancy has more than one network, and default cannot be determined. Please refer to your OpenStack manual whether it wants net-id or net-name.

Other useful parameters are availability_zonesecurity_groups and config_drive. Refer to Python bindings to the OpenStack Nova API for more information. It is found on section Servers, method create.

from buildbot.plugins import worker
c['workers'] = [
    worker.OpenStackLatentWorker('bot2', 'sekrit',
                flavor=1, image='8ac9d4a4-5e03-48b0-acde-77a0345a9ab1',
                os_username='user', os_password='password',
                  'nics': [

OpenStackLatentWorker supports all other configuration from the standard Worker. The missing_timeoutand notify_on_missing specify how long to wait for an OpenStack instance to attach before considering the attempt to have failed and email addresses to alert, respectively. missing_timeoutdefaults to 20 minutes.

Docker latent worker

class buildbot.worker.docker.DockerLatentWorker
class buildbot.plugins.worker.DockerLatentWorker

Docker is an open-source project that automates the deployment of applications inside software containers. The DockerLatentWorker attempts to instantiate a fresh image for each build to assure consistency of the environment between builds. Each image will be discarded once the worker finished processing the build queue (i.e. becomes idle). See build_wait_timeout to change this behavior.

This document will guide you through the setup of such workers.

Docker Installation

An easy way to try Docker is through installation of dedicated Virtual machines. Two of them stands out:

Beside, it is always possible to install Docker next to the buildmaster. Beware that in this case, overall performance will depend on how many builds the computer where you have your buildmaster can handle as everything will happen on the same one.


It is not necessary to install Docker in the same environment as your master as we will make use to the Docker API through docker-py. More in master setup.


CoreOS is targeted at building infrastructure and distributed systems. In order to get the latent worker working with CoreOS, it is necessary to expose the docker socket outside of the Virtual Machine. If you installed it via Vagrant, it is also necessary to uncomment the following line in your config.rb file:


The following command should allow you to confirm that your Docker socket is now available via the network:

docker -H tcp:// ps


boot2docker is one of the fastest ways to boot to Docker. As it is meant to be used from outside of the Virtual Machine, the socket is already exposed. Please follow the installation instructions on how to find the address of your socket.

Image Creation

Our build master will need the name of an image to perform its builds. Each time a new build will be requested, the same base image will be used again and again, actually discarding the result of the previous build. If you need some persistent storage between builds, you can use Volumes.

Each Docker image has a single purpose. Our worker image will be running a buildbot worker.

Docker uses Dockerfiles to describe the steps necessary to build an image. The following example will build a minimal worker. This example is voluntarily simplistic, and should probably not be used in production, see next paragraph.

FROM debian:stable
RUN apt-get update && apt-get install -y \
   python-dev \
RUN pip install buildbot-worker
RUN groupadd -r buildbot && useradd -r -g buildbot buildbot
RUN mkdir /worker && chown buildbot:buildbot /worker
# Install your build-dependencies here ...
USER buildbot
WORKDIR /worker
RUN buildbot-worker create-worker . <master-hostname> <workername> <workerpassword>
ENTRYPOINT ["/usr/local/bin/buildbot-worker"]
CMD ["start", "--nodaemon"]

On line 11, the hostname for your master instance, as well as the worker name and password is setup. Don’t forget to replace those values with some valid ones for your project.

It is a good practice to set the ENTRYPOINT to the worker executable, and the CMD to ["start", "--nodaemon"]. This way, no parameter will be required when starting the image.

When your Dockerfile is ready, you can build your first image using the following command (replace myworkername with a relevant name for your case):

docker build -t myworkername - < Dockerfile

Reuse same image for different workers

Previous simple example hardcodes the worker name into the dockerfile, which will not work if you want to share your docker image between workers.

You can find in buildbot source code in master/contrib/docker one example configurations:

a worker with Python and node installed, which demonstrate how to reuse the base worker to create variations of build environments. It is based on the official buildbot/buildbot-worker image.

The master setups several environment variables before starting the workers:

The address of the master the worker shall connect to
The port of the master’s worker ‘pb’ protocol.
The name the worker should use to connect to master
The password the worker should use to connect to master

Master Setup

We will rely on docker-py to connect our master with docker. Now is the time to install it in your master environment.

Before adding the worker to your master configuration, it is possible to validate the previous steps by starting the newly created image interactively. To do this, enter the following lines in a Python prompt where docker-py is installed:

>>> import docker
>>> docker_socket = 'tcp://localhost:2375'
>>> client = docker.client.Client(base_url=docker_socket)
>>> worker_image = 'my_project_worker'
>>> container = client.create_container(worker_image)
>>> client.start(container['Id'])
>>> # Optionally examine the logs of the master
>>> client.stop(container['Id'])
>>> client.wait(container['Id'])

It is now time to add the new worker to the master configuration under workers.

The following example will add a Docker latent worker for docker running at the following address: tcp://localhost:2375, the worker name will be docker, its password: password, and the base image name will be my_project_worker:

from buildbot.plugins import worker
c['workers'] = [
    worker.DockerLatentWorker('docker', 'password',
(mandatory) The worker password part of the Latent Workers API. If the password is None, then it will be automatically generated from random number, and transmitted to the container via environment variable.

In addition to the arguments available for any Latent WorkersDockerLatentWorker will accept the following extra ones:

(mandatory) This is the address the master will use to connect with a running Docker instance.


This is the name of the image that will be started by the build master. It should start a worker. This option can be a renderable, like Interpolate, so that it generates from the build request properties.

(optional) This will override the command setup during image creation.
(optional) See Setting up Volumes

(optional if image is given) This is the content of the Dockerfile that will be used to build the specified image if the image is not found by Docker. It should be a multiline string.


In case image and dockerfile are given, no attempt is made to compare the image with the content of the Dockerfile parameter if the image is found.

(optional, default to the highest version known by docker-py) This will indicates which API version must be used to communicate with Docker.
(optional) This allow to use TLS when connecting with the Docker socket. This should be a docker.tls.TLSConfig object. See docker-py’s own documentation for more details on how to initialise this object.
(optional, defaults to false) This transfers docker container’s log inside master logs during worker startup (before connection). This can be useful to debug worker startup. e.g network issues, etc.
(optional, defaults to socket.getfqdn()) Address of the master the worker should connect to. Use if you master machine does not have proper fqdn. This value is passed to the docker image via environment variable BUILDMASTER
(optional) Extra host configuration parameters passed as a dictionary used to create HostConfig object. See docker-py’s HostConfig documentation for all the supported options.
(optional, defaults to false) Automatically pulls image if requested image is not on docker host.
(optional, defaults to false) Always pulls image if autopull is set to true.

Setting up Volumes

The volume parameter allows to share directory between containers, or between a container and the host system. Refer to Docker documentation for more information about Volumes.

The format of that variable has to be an array of string. Each string specify a volume in the following format: volumename:bindname. The volume name has to be appended with :ro if the volume should be mounted read-only.


This is the same format as when specifying volumes on the command line for docker’s own -voption.

Hyper latent worker

Hyper is a CaaS solution for hosting docker container in the cloud, billed to the second. It forms a very cost efficient solution to run your CI in the cloud.

Buildbot supports using Hyper to host your latent workers.

class buildbot.worker.hyper.HyperLatentWorker
class buildbot.plugins.worker.HyperLatentWorker

The HyperLatentWorker attempts to instantiate a fresh image for each build to assure consistency of the environment between builds. Each image will be discarded once the worker finished processing the build queue (i.e. becomes idle). See build_wait_timeout to change this behavior.

In addition to the arguments available for any Latent WorkersHyperLatentWorker will accept the following extra ones:

(mandatory) The worker password part of the Latent Workers API. If the password is None, then it will be automatically generated from random number, and transmitted to the container via environment variable.
(mandatory) This is the address the hyper infra endpoint will use to start docker containers.
(mandatory) This is the name of the image that will be started by the build master. It should start a worker. This option can be a renderable, like Interpolate, so that it generates from the build request properties. Images are by default pulled from the public DockerHub docker registry. You can consult the hyper documentation to know how to configure a custom registry. HyperLatentWorker does not support starting a worker built from a Dockerfile.

(optional, defaults to socket.getfqdn()) Address of the master the worker should connect to. Use if you master machine does not have proper fqdn. This value is passed to the docker image via environment variable BUILDMASTER

If the value contains a colon (:), then BUILDMASTER and BUILDMASTER_PORT environment variables will be passed, following scheme: masterFQDN="$BUILDMASTER:$BUILDMASTER_PORT"

This feature is useful for testing behind a proxy using ngrok command like: ngrok tcp 9989 ngrokconfig can the be retrieved with following snippet:

from future.moves.urllib.parse import urlparse
import requests
r = requests.get("http://localhost:4040/api/tunnels/command_line").json()
masterFQDN = urlparse(r['public_url']).netloc
(mandatory) Access key to use as part of the creds to access hyper.
(mandatory) Secret key to use as part of the creds to access hyper.
(optional, defaults to s3) Size of the container to use as per HyperPricing

Marathon latent worker

Marathon Marathon is a production-grade container orchestration platform for Mesosphere’s Data-center Operating System (DC/OS) and Apache Mesos.

Buildbot supports using Marathon to host your latent workers. It requires either txrequests or treq to be installed to allow interaction with http server. See HTTPClientService for details.

class buildbot.worker.marathon.MarathonLatentWorker
class buildbot.plugins.worker.MarathonLatentWorker

The MarathonLatentWorker attempts to instantiate a fresh image for each build to assure consistency of the environment between builds. Each image will be discarded once the worker finished processing the build queue (i.e. becomes idle). See build_wait_timeout to change this behavior.

In addition to the arguments available for any Latent WorkersMarathonLatentWorker will accept the following extra ones:

(mandatory) This is the URL to Marathon server. Its REST API will be used to start docker containers.
(optional) This is the optional ('userid', 'password') BasicAuth credential. If txrequests is installed, this can be a requests authentication plugin.
(mandatory) This is the name of the image that will be started by the build master. It should start a worker. This option can be a renderable, like Interpolate, so that it generates from the build request properties. Images are by pulled from the default docker registry. MarathonLatentWorker does not support starting a worker built from a Dockerfile.

(optional, defaults to socket.getfqdn()) Address of the master the worker should connect to. Use if you master machine does not have proper fqdn. This value is passed to the docker image via environment variable BUILDMASTER

If the value contains a colon (:), then BUILDMASTER and BUILDMASTER_PORT environment variables will be passed, following scheme: masterFQDN="$BUILDMASTER:$BUILDMASTER_PORT"

(optional, defaults to {}`) Extra configuration to be passed to Marathon API. This implementation will setup the minimal configuration to run a worker (docker image, BRIDGED network) It will let the default for everything else, including memory size, volume mounting, etc. This configuration is voluntarily very raw so that it is easy to use new marathon features. This dictionary will be merged into the Buildbot generated config, and recursively override it. See Marathon APIdocumentation to learn what to include in this config.
Dangers with Latent Workers

Any latent worker that interacts with a for-fee service, such as the EC2LatentWorker, brings significant risks. As already identified, the configuration will need access to account information that, if obtained by a criminal, can be used to charge services to your account. Also, bugs in the Buildbot software may lead to unnecessary charges. In particular, if the master neglects to shut down an instance for some reason, a virtual machine may be running unnecessarily, charging against your account. Manual and/or automatic (e.g. Nagios with a plugin using a library like boto) double-checking may be appropriate.

A comparatively trivial note is that currently if two instances try to attach to the same latent worker, it is likely that the system will become confused. This should not occur, unless, for instance, you configure a normal worker to connect with the authentication of a latent buildbot. If this situation does occurs, stop all attached instances and restart the master.

2.5.7. Builder Configuration

The builders configuration key is a list of objects giving configuration for the Builders. For more information on the function of Builders in Buildbot, see the Concepts chapter. The class definition for the builder configuration is in buildbot.config. However there is a much simpler way to use it, so in the configuration file, its use looks like:

from buildbot.plugins import util
c['builders'] = [
    util.BuilderConfig(name='quick', workernames=['bot1', 'bot2'], factory=f_quick),
    util.BuilderConfig(name='thorough', workername='bot1', factory=f_thorough),

BuilderConfig takes the following keyword arguments:

This specifies the Builder’s name, which is used in status reports.


These arguments specify the worker or workers that will be used by this Builder. All workers names must appear in the workers configuration parameter. Each worker can accommodate multiple builders. The workernames parameter can be a list of names, while workername can specify only one worker.
This is a buildbot.process.factory.BuildFactory instance which controls how the build is performed by defining the steps in the build. Full details appear in their own section, Build Factories.

Other optional keys may be set on each BuilderConfig:

Specifies the name of a subdirectory of the master’s basedir in which everything related to this builder will be stored. This holds build status information. If not set, this parameter defaults to the builder name, with some characters escaped. Each builder must have a unique build directory.
Specifies the name of a subdirectory (under the worker’s configured base directory) in which everything related to this builder will be placed on the worker. This is where checkouts, compiles, and tests are run. If not set, defaults to builddir. If a worker is connected to multiple builders that share the same workerbuilddir, make sure the worker is set to run one build at a time or ensure this is fine to run multiple builds from the same directory simultaneously.
If provided, this is a list of strings that identifies tags for the builder. Status clients can limit themselves to a subset of the available tags. A common use for this is to add new builders to your setup (for a new module, or for a new worker) that do not work correctly yet and allow you to integrate them with the active builders. You can tag these new builders with a test tag, make your main status clients ignore them, and have only private status clients pick them up. As soon as they work, you can move them over to the active tag.
If provided, this is a function that controls which worker will be assigned future jobs. The function is passed three arguments, the Builder object which is assigning a new job, a list of WorkerForBuilder objects and the BuildRequest. The function should return one of the WorkerForBuilder objects, or None if none of the available workers should be used. As an example, for each worker in the list, worker.worker will be a Worker object, and worker.worker.workername is the worker’s name. The function can optionally return a Deferred, which should fire with the same results.
If provided, this is a function that controls which build request will be handled next. The function is passed two arguments, the Builder object which is assigning a new job, and a list of BuildRequest objects of pending builds. The function should return one of the BuildRequestobjects, or None if none of the pending builds should be started. This function can optionally return a Deferred which should fire with the same results.

If provided, this is a function that can veto whether a particular worker should be used for a given build request. The function is passed three arguments: the Builder, a Worker, and a BuildRequest. The function should return True if the combination is acceptable, or False otherwise. This function can optionally return a Deferred which should fire with the same results.

See canStartBuild Functions for a concrete example.

A list of Locks (instances of buildbot.locks.WorkerLock or buildbot.locks.MasterLock) that should be acquired before starting a Build from this Builder. Alternatively this could be a renderable that returns this list depending on properties of related to a build that is just about to be created. This lets you defer picking the locks to acquire until it is known which Worker a build would get assigned to. The properties available to the renderable include all properties that are set to the build before its first step excluding the properties that come from the build itself and the builddirproperty that comes from worker. The Locks will be released when the build is complete. Note that this is a list of actual Lock instances, not names. Also note that all Locks must have unique names. See Interlocks.

A Builder may be given a dictionary of environment variables in this parameter. The variables are used in ShellCommand steps in builds created by this builder. The environment variables will override anything in the worker’s environment. Variables passed directly to a ShellCommand will override variables of the same name passed to the Builder.

For example, if you have a pool of identical workers it is often easier to manage variables like PATH from Buildbot rather than manually editing it inside of the workers’ environment.

f = factory.BuildFactory
              command=['bash', './configure']))

c['builders'] = [
  BuilderConfig(name='test', factory=f,
        workernames=['worker1', 'worker2', 'worker3', 'worker4'],
        env={'PATH': '/opt/local/bin:/opt/app/bin:/usr/local/bin:/usr/bin'}),

Unlike most builder configuration arguments, this argument can contain renderables.

Specifies how build requests for this builder should be collapsed. See Collapsing Build Requests, below.
A builder may be given a dictionary of Build Properties specific for this builder in this parameter. Those values can be used later on like other properties. Interpolate.
Similar to the properties parameter. But defaultProperties will only be added to Build Propertiesif they are not already set by another source.
A builder may be given an arbitrary description, which will show up in the web status on the builder’s page. Collapsing Build Requests

When more than one build request is available for a builder, Buildbot can “collapse” the requests into a single build. This is desirable when build requests arrive more quickly than the available workers can satisfy them, but has the drawback that separate results for each build are not available.

Requests are only candidated for a merge if both requests have exactly the same codebases.

This behavior can be controlled globally, using the collapseRequests parameter, and on a per-Builderbasis, using the collapseRequests argument to the Builder configuration. If collapseRequests is given, it completely overrides the global configuration.

Possible values for both collapseRequests configurations are:

Requests will be collapsed if their sourcestamp are compatible (see below for definition of compatible).
Requests will never be collapsed.
callable(builder, req1, req2)
Requests will be collapsed if the callable returns true. See Collapse Request Functions for detailed example.

Sourcestamps are compatible if all of the below conditions are met:

  • Their codebase, branch, project, and repository attributes match exactly
  • Neither source stamp has a patch (e.g., from a try scheduler)
  • Either both source stamps are associated with changes, or neither are associated with changes but they have matching revisions. Prioritizing Builds

The BuilderConfig parameter nextBuild can be use to prioritize build requests within a builder. Note that this is orthogonal to Prioritizing Builders, which controls the order in which builders are called on to start their builds. The details of writing such a function are in Build Priority Functions.

Such a function can be provided to the BuilderConfig as follows:

def pickNextBuild(builder, requests):
c['builders'] = [
    BuilderConfig(name='test', factory=f,
        workernames=['worker1', 'worker2', 'worker3', 'worker4']),
] Virtual Builders

Dynamic Trigger is a method which allows to trigger the same builder, with different parameters. This method is used by frameworks which store the build config along side the source code like Buildbot_travis. The drawback of this method is that it is difficult to extract statistics for similar builds. The standard dashboards are not working well due to the fact that all the builds are on the same builder.

In order to overcome those drawbacks, Buildbot has the concept of virtual builder. If a build has the property virtual_builder_name, it will automatically attach to that builder instead of the original builder. That created virtual builder is not attached to any master and is only used for better sorting in the UI and better statistics. The original builder and worker configuration is still used for all other build behaviors.

The virtual builder metadata is configured with the following properties:

  • virtual_builder_name: The name of the virtual builder.
  • virtual_builder_description: The description of the virtual builder.
  • virtual_builder_tags: The tags for the virtual builder.

2.5.8. Build Factories

Each Builder is equipped with a build factory, which defines the steps used to perform that particular type of build. This factory is created in the configuration file, and attached to a Builder through the factory element of its dictionary.

The steps used by these builds are defined in the next section, Build Steps.


Build factories are used with builders, and are not added directly to the buildmaster configuration dictionary. Defining a Build Factory

BuildFactory defines the steps that every build will follow. Think of it as a glorified script. For example, a build factory which consists of an SVN checkout followed by a make build would be configured as follows:

from buildbot.plugins import util, steps

f = util.BuildFactory()
f.addStep(steps.SVN(repourl="http://..", mode="incremental"))
f.addStep(steps.Compile(command=["make", "build"]))

This factory would then be attached to one builder (or several, if desired):

    BuilderConfig(name='quick', workernames=['bot1', 'bot2'], factory=f))

It is also possible to pass a list of steps into the BuildFactory when it is created. Using addStep is usually simpler, but there are cases where it is more convenient to create the list of steps ahead of time, perhaps using some Python tricks to generate the steps.

from buildbot.plugins import steps, util

all_steps = [
    steps.CVS(cvsroot=CVSROOT, cvsmodule="project", mode="update"),
    steps.Compile(command=["make", "build"]),
f = util.BuildFactory(all_steps)

Finally, you can also add a sequence of steps all at once:


The following attributes can be set on a build factory after it is created, e.g.,

f = util.BuildFactory()
f.useProgress = False
(defaults to True): if True, the buildmaster keeps track of how long each step takes, so it can provide estimates of how long future builds will take. If builds are not expected to take a consistent amount of time (such as incremental builds in which a random set of files are recompiled or tested each time), this should be set to False to inhibit progress-tracking.

(defaults to ‘build’): workdir given to every build step created by this factory as default. The workdir can be overridden in a build step definition.

If this attribute is set to a string, that string will be used for constructing the workdir (worker base + builder builddir + workdir). The attribute can also be a Python callable, for more complex cases, as described in Factory Workdir Functions. Dynamic Build Factories

In some cases you may not know what commands to run until after you checkout the source tree. For those cases you can dynamically add steps during a build from other steps.

The Build object provides 2 functions to do this:

addStepsAfterCurrentStep(self, step_factories)
This adds the steps after the step that is currently executing.
addStepsAfterLastStep(self, step_factories)
This adds the steps onto the end of the build.

Both functions only accept as an argument a list of steps to add to the build.

For example lets say you have a script checked in into your source tree called When this script is called with the argument --list-stages it outputs a newline separated list of stage names. This can be used to generate at runtime a step for each stage in the build. Each stage is then run in this example using ./ --run-stage <stage name>.

from buildbot.plugins import util, steps
from buildbot.process import buildstep, logobserver
from twisted.internet import defer

class GenerateStagesCommand(buildstep.ShellMixin, steps.BuildStep):

    def __init__(self, **kwargs):
        kwargs = self.setupShellMixin(kwargs)
        steps.BuildStep.__init__(self, **kwargs) = logobserver.BufferLogObserver()

    def extract_stages(self, stdout):
        stages = []
        for line in stdout.split('\n'):
            stage = str(line.strip())
            if stage:
        return stages

    def run(self):
        # run './ --list-stages' to generate the list of stages
        cmd = yield self.makeRemoteShellCommand()
        yield self.runCommand(cmd)

        # if the command passes extract the list of stages
        result = cmd.results()
        if result == util.SUCCESS:
            # create a ShellCommand for each stage and add them to the build
                steps.ShellCommand(name=stage, command=["./", "--run-stage", stage])
                for stage in self.extract_stages(


f = util.BuildFactory()
    name="Generate build stages",
    command=["./", "--list-stages"],
    haltOnFailure=True)) Predefined Build Factories

Buildbot includes a few predefined build factories that perform common build sequences. In practice, these are rarely used, as every site has slightly different requirements, but the source for these factories may provide examples for implementation of those requirements.

class buildbot.process.factory.GNUAutoconf

GNU Autoconf is a software portability tool, intended to make it possible to write programs in C (and other languages) which will run on a variety of UNIX-like systems. Most GNU software is built using autoconf. It is frequently used in combination with GNU automake. These tools both encourage a build process which usually looks like this:

% CONFIG_ENV=foo ./configure --with-flags
% make all
% make check
# make install

(except of course the Buildbot always skips the make install part).

The Buildbot’s buildbot.process.factory.GNUAutoconf factory is designed to build projects which use GNU autoconf and/or automake. The configuration environment variables, the configure flags, and command lines used for the compile and test are all configurable, in general the default values will be suitable.


f = util.GNUAutoconf(source=source.SVN(repourl=URL, mode="copy"),

Required Arguments:

This argument must be a step specification tuple that provides a BuildStep to generate the source tree.

Optional Arguments:

The command used to configure the tree. Defaults to ./configure. Accepts either a string or a list of shell argv elements.
The environment used for the initial configuration step. This accepts a dictionary which will be merged into the worker’s normal environment. This is commonly used to provide things like CFLAGS="-O2 -g" (to turn off debug symbols during the compile). Defaults to an empty dictionary.
A list of flags to be appended to the argument list of the configure command. This is commonly used to enable or disable specific features of the autoconf-controlled package, like ["--without-x"] to disable windowing support. Defaults to an empty list.
use autoreconf to generate the ./configure file, set to True to use a buildbot default autoreconf command, or define the command for the ShellCommand.
this is a shell command or list of argv values which is used to actually compile the tree. It defaults to make all. If set to None, the compile step is skipped.
this is a shell command or list of argv values which is used to run the tree’s self-tests. It defaults to make check. If set to None, the test step is skipped.
this is a shell command or list of argv values which is used to run the packaging test. It defaults to make distcheck. If set to None, the test step is skipped.
class buildbot.process.factory.BasicBuildFactory

This is a subclass of GNUAutoconf which assumes the source is in CVS, and uses mode='full' and method='clobber' to always build from a clean working copy.

class buildbot.process.factory.BasicSVN

This class is similar to QuickBuildFactory, but uses SVN instead of CVS.

class buildbot.process.factory.QuickBuildFactory

The QuickBuildFactory class is a subclass of GNUAutoconf which assumes the source is in CVS, and uses mode='incremental' to get incremental updates.

The difference between a full build and a quick build is that quick builds are generally done incrementally, starting with the tree where the previous build was performed. That simply means that the source-checkout step should be given a mode='incremental' flag, to do the source update in-place.

In addition to that, this class sets the useProgress flag to False. Incremental builds will (or at least the ought to) compile as few files as necessary, so they will take an unpredictable amount of time to run. Therefore it would be misleading to claim to predict how long the build will take.

This class is probably not of use to new projects.

class buildbot.process.factory.CPAN

Most Perl modules available from the CPAN archive use the MakeMaker module to provide configuration, build, and test services. The standard build routine for these modules looks like:

% perl Makefile.PL
% make
% make test
# make install

(except again Buildbot skips the install step)

Buildbot provides a CPAN factory to compile and test these projects.


(required): A step specification tuple, like that used by GNUAutoconf.
A string which specifies the perl executable to use. Defaults to just perl.
class buildbot.process.factory.Distutils

Most Python modules use the distutils package to provide configuration and build services. The standard build process looks like:

% python ./ build
% python ./ install

Unfortunately, although Python provides a standard unit-test framework named unittest, to the best of my knowledge distutils does not provide a standardized target to run such unit tests. (Please let me know if I’m wrong, and I will update this factory.)

The Distutils factory provides support for running the build part of this process. It accepts the same source= parameter as the other build factories.


(required): A step specification tuple, like that used by GNUAutoconf.
A string which specifies the python executable to use. Defaults to just python.
Provides a shell command which runs unit tests. This accepts either a string or a list. The default value is None, which disables the test step (since there is no common default command to run unit tests in distutils modules).
class buildbot.process.factory.Trial

Twisted provides a unit test tool named trial which provides a few improvements over Python’s built-in unittest module. Many Python projects which use Twisted for their networking or application services also use trial for their unit tests. These modules are usually built and tested with something like the following:

% python ./ build
% PYTHONPATH=build/lib.linux-i686-2.3 trial -v PROJECTNAME.test
% python ./ install

Unfortunately, the build/lib directory into which the built/copied .py files are placed is actually architecture-dependent, and I do not yet know of a simple way to calculate its value. For many projects it is sufficient to import their libraries in place from the tree’s base directory (PYTHONPATH=.).

In addition, the PROJECTNAME value where the test files are located is project-dependent: it is usually just the project’s top-level library directory, as common practice suggests the unit test files are put in the test sub-module. This value cannot be guessed, the Trial class must be told where to find the test files.

The Trial class provides support for building and testing projects which use distutils and trial. If the test module name is specified, trial will be invoked. The library path used for testing can also be set.

One advantage of trial is that the Buildbot happens to know how to parse trial output, letting it identify which tests passed and which ones failed. The Buildbot can then provide fine-grained reports about how many tests have failed, when individual tests fail when they had been passing previously, etc.

Another feature of trial is that you can give it a series of source .py files, and it will search them for special test-case-name tags that indicate which test cases provide coverage for that file. Trial can then run just the appropriate tests. This is useful for quick builds, where you want to only run the test cases that cover the changed functionality.


Provides a directory to add to PYTHONPATH when running the unit tests, if tests are being run. Defaults to . to include the project files in-place. The generated build library is frequently architecture-dependent, but may simply be build/lib for pure-Python modules.
which Python executable to use. This list will form the start of the argv array that will launch trial. If you use this, you should set trial to an explicit path (like /usr/bin/trial or ./bin/trial). The parameter defaults to None, which leaves it out entirely (running trial args instead of python./bin/trial args). Likely values are ['python']['python2.2'], or ['python', '-Wall'].
provides the name of the trial command. It is occasionally useful to use an alternate executable, such as trial2.2 which might run the tests under an older version of Python. Defaults to trial.
a list of arguments to pass to trial, specifically to set the reporting mode. This defaults to ['--reporter=bwverbose'], which only works for Twisted-2.1.0 and later.
a list of arguments to pass to trial, available to turn on any extra flags you like. Defaults to [].
Provides a module name or names which contain the unit tests for this project. Accepts a string, typically PROJECTNAME.test, or a list of strings. Defaults to None, indicating that no tests should be run. You must either set this or testChanges.
if True, ignore the tests parameter and instead ask the Build for all the files that make up the Changes going into this build. Pass these filenames to trial and ask it to look for test-case-name tags, running just the tests necessary to cover the changes.
If True, tells Trial (with the --recurse argument) to look in all subdirectories for additional test cases.
which reactor to use, like ‘gtk’ or ‘java’. If not provided, the Twisted’s usual platform-dependent default is used.
If True, tells Trial (with the --random=0 argument) to run the test cases in random order, which sometimes catches subtle inter-test dependency bugs. Defaults to False.

The step can also take any of the ShellCommand arguments, e.g., haltOnFailure.

Unless one of tests or testChanges are set, the step will generate an exception.

2.5.9. Properties

Build properties are a generalized way to provide configuration information to build steps; see Build Properties for the conceptual overview of properties.

Some build properties come from external sources and are set before the build begins; others are set during the build, and available for later steps. The sources for properties are:

global configuration
These properties apply to all builds.
A scheduler can specify properties that become available to all builds it starts.
A change can have properties attached to it, supplying extra information gathered by the change source. This is most commonly used with the sendchange command.
forced builds
The “Force Build” form allows users to specify properties
A worker can pass properties on to the builds it performs.
A build automatically sets a number of properties on itself.
A builder can set properties on all the builds it runs.
The steps of a build can set properties that are available to subsequent steps. In particular, source steps set the got_revision property.

If the same property is supplied in multiple places, the final appearance takes precedence. For example, a property set in a builder configuration will override one supplied by a scheduler.

Properties are stored internally in JSON format, so they are limited to basic types of data: numbers, strings, lists, and dictionaries. Common Build Properties

The following build properties are set when the build is started, and are available to all steps.


This property is set when a Source step checks out the source tree, and provides the revision that was actually obtained from the VC system. In general this should be the same as revision, except for non-absolute sourcestamps, where got_revision indicates what revision was current when the checkout was performed. This can be used to rebuild the same source code later.


For some VC systems (Darcs in particular), the revision is a large string containing newlines, and is not suitable for interpolation into a filename.

For multi-codebase builds (where codebase is not the default ‘’), this property is a dictionary, keyed by codebase.

This is a string that indicates which Builder the build was a part of. The combination of buildername and buildnumber uniquely identify a build.
Each build gets a number, scoped to the Builder (so the first build performed on any given Builder will have a build number of 0). This integer property contains the build’s number.
This is a string which identifies which worker the build is running on.
If the build was started from a scheduler, then this property will contain the name of that scheduler.
The absolute path of the base working directory on the worker, of the current builder.

For single codebase builds, where the codebase is ‘’, the following Source Stamp Attributes are also available as properties: branchrevisionrepository, and project . Source Stamp Attributes

branch revision repository project codebase

For details of these attributes see Concepts.


This attribute is a list of dictionaries representing the changes that make up this sourcestamp. Using Properties in Steps

For the most part, properties are used to alter the behavior of build steps during a build. This is done by using renderables (objects implementing the IRenderable interface) as step parameters. When the step is started, each such object is rendered using the current values of the build properties, and the resultant rendering is substituted as the actual value of the step parameter.

Buildbot offers several renderable object types covering common cases. It’s also possible to create custom renderables.


Properties are defined while a build is in progress; their values are not available when the configuration file is parsed. This can sometimes confuse newcomers to Buildbot! In particular, the following is a common error:

if Property('release_train') == 'alpha':

This does not work because the value of the property is not available when the if statement is executed. However, Python will not detect this as an error - you will just never see the step added to the factory.

You can use renderables in most step parameters. Please file bugs for any parameters which do not accept renderables.


The simplest renderable is Property, which renders to the value of the property named by its argument:

from buildbot.plugins import steps, util

f.addStep(steps.ShellCommand(command=['echo', 'buildername:',

You can specify a default value by passing a default keyword argument:

f.addStep(steps.ShellCommand(command=['echo', 'warnings:',
                             util.Property('warnings', default='none')]))

The default value is used when the property doesn’t exist, or when the value is something Python regards as False. The defaultWhenFalse argument can be set to False to force buildbot to use the default argument only if the parameter is not set:

f.addStep(steps.ShellCommand(command=['echo', 'warnings:',
                             util.Property('warnings', default='none',

The default value can be a renderable itself, e.g.,

command=util.Property('command', default=util.Property('default-command'))

Property can only be used to replace an entire argument: in the example above, it replaces an argument to echo. Often, properties need to be interpolated into strings, instead. The tool for that job is Interpolate.

The more common pattern is to use Python dictionary-style string interpolation by using the %(prop:<propname>)s syntax. In this form, the property name goes in the parentheses, as above. A common mistake is to omit the trailing “s”, leading to a rather obscure error from Python (“ValueError: unsupported format character”).

from buildbot.plugins import steps, util

This example will result in a make command with an argument like REVISION=12098.

The syntax of dictionary-style interpolation is a selector, followed by a colon, followed by a selector specific key, optionally followed by a colon and a string indicating how to interpret the value produced by the key.

The following selectors are supported.

The key is the name of a property.
The key is a codebase and source stamp attribute, separated by a colon. Note, it is %(src:<codebase>:<ssattr>)s syntax, which differs from other selectors.
The key refers to a keyword argument passed to Interpolate. Those keyword arguments may be ordinary values or renderables.
The key refers to a secret provided by a provider declared in secretsProviders .

The following ways of interpreting the value are available.

If the key exists, substitute its value; otherwise, substitute replacementreplacement may be empty (%(prop:propname:-)s). This is the default.
Like -replacement, but only substitutes the value of the key if it is something Python regards as True. Python considers None, 0, empty lists, and the empty string to be false, so such values will be replaced by replacement.
If the key exists, substitute replacement; otherwise, substitute an empty string.


Ternary substitution, depending on either the key being present (with ?, similar to +) or being True(with #?, like ~). Notice that there is a pipe immediately following the question mark and between the two substitution alternatives. The character that follows the question mark is used as the delimiter between the two alternatives. In the above examples, it is a pipe, but any character other than ( can be used.


Although these are similar to shell substitutions, no other substitutions are currently supported.


from buildbot.plugins import steps, util
        util.Interpolate('-r %(prop:repository)s'),
        util.Interpolate('-b %(src::branch)s'),
        util.Interpolate('-d %(kw:data)s', data="some extra needed data")


We use %(src::branch)s in most of examples, because codebase is empty by default.


from buildbot.plugins import steps, util

In addition, Interpolate supports using positional string interpolation. Here, %s is used as a placeholder, and the substitutions (which may be renderables), are given as subsequent arguments:



Like Python, you can use either positional interpolation or dictionary-style interpolation, not both. Thus you cannot use a string like Interpolate("foo-%(src::revision)s-%s", "branch").


While Interpolate can handle many simple cases, and even some common conditionals, more complex cases are best handled with Python code. The renderer decorator creates a renderable object whose rendering is obtained by calling the decorated function when the step it’s passed to begins. The function receives an IProperties object, which it can use to examine the values of any and all properties. For example:

from buildbot.plugins import steps, util

def makeCommand(props):
    command = ['make']
    cpus = props.getProperty('CPUs')
    if cpus:
        command.extend(['-j', str(cpus+1)])
        command.extend(['-j', '2'])
    return command


You can think of renderer as saying “call this function when the step starts”.


Since 0.9.3, renderer can itself return IRenderable objects or containers containing IRenderable.

Optionally, extra arguments may be passed to the rendered function at any time by calling withArgson the renderable object. The withArgs method accepts *args and **kwargs arguments which are stored in a new renderable object which is returned. The original renderable object is not modified. Multiple withArgs calls may be chained. The passed *args and **kwargs parameters are rendered and the results are passed to the rendered function at the time it is itself rendered. For example:

from buildbot.plugins import steps, util

def makeCommand(props, target):
    command = ['make']
    cpus = props.getProperty('CPUs')
    if cpus:
        command.extend(['-j', str(cpus+1)])
        command.extend(['-j', '2'])
    return command



The rendering of the renderable object may happen at unexpected times, so it is best to ensure that the passed extra arguments are not changed.


Config errors with Renderables may not always be caught via checkconfig


Transform is an alternative to renderer. While renderer is useful for creating new renderables, Transformis easier to use when you want to transform or combine the renderings of preexisting ones.

Transform takes a function and any number of positional and keyword arguments. The function must either be a callable object or a renderable producing one. When rendered, a Transform first replaces all of its arguments that are renderables with their renderings, then calls the function, passing it the positional and keyword arguments, and returns the result as its own rendering.

For example, suppose my_path is a path on the worker, and you want to get it relative to the build directory. You can do it like this:

import os.path
from buildbot.plugins import util

my_path_rel = util.Transform(os.path.relpath, my_path, start=util.Property('builddir'))

This works whether my_path is an ordinary string or a renderable. my_path_rel will be a renderable in either case, however.


If nested list should be flatten for some renderables, FlattenList could be used. For example:

from buildbot.plugins import steps, util
    command=[ 'make' ],
    descriptionDone=util.FlattenList([ 'make ', [ 'done' ]])

descriptionDone would be set to [ 'make', 'done' ] when the ShellCommand executes. This is useful when a list-returning property is used in renderables.


ShellCommand automatically flattens nested lists in its command argument, so there is no need to use FlattenList for it.



This class is deprecated. It is an older version of Interpolate. It exists for compatibility with older configs.

The simplest use of this class is with positional string interpolation. Here, %s is used as a placeholder, and property names are given as subsequent arguments:

from buildbot.plugins import steps, util
    command=["tar", "czf",
            util.WithProperties("build-%s-%s.tar.gz", "branch", "revision"),

If this BuildStep were used in a tree obtained from Git, it would create a tarball with a name like build-master-a7d3a333db708e786edb34b6af646edd8d4d3ad9.tar.gz.

The more common pattern is to use Python dictionary-style string interpolation by using the %(propname)s syntax. In this form, the property name goes in the parentheses, as above. A common mistake is to omit the trailing “s”, leading to a rather obscure error from Python (“ValueError: unsupported format character”).

from buildbot.plugins import steps, util

This example will result in a make command with an argument like REVISION=12098.

The dictionary-style interpolation supports a number of more advanced syntaxes in the parentheses.

If propname exists, substitute its value; otherwise, substitute replacementreplacement may be empty (%(propname:-)s)
Like propname:-replacement, but only substitutes the value of property propname if it is something Python regards as True. Python considers None, 0, empty lists, and the empty string to be false, so such values will be replaced by replacement.
If propname exists, substitute replacement; otherwise, substitute an empty string.

Although these are similar to shell substitutions, no other substitutions are currently supported, and replacement in the above cannot contain more substitutions.

Note: like Python, you can use either positional interpolation or dictionary-style interpolation, not both. Thus you cannot use a string like WithProperties("foo-%(revision)s-%s", "branch").

Custom Renderables

If the options described above are not sufficient, more complex substitutions can be achieved by writing custom renderables.

The IRenderable interface is simple - objects must provide a getRenderingFor method. The method should take one argument - an IProperties provider - and should return the rendered value or a deferred firing with one. Pass instances of the class anywhere other renderables are accepted. For example:

import time
from buildbot.interfaces import IRenderable
from zope.interface import implementer

class DetermineFoo(object):
    def getRenderingFor(self, props):
        if props.hasProperty('bar'):
            return props['bar']
        elif props.hasProperty('baz'):
            return props['baz']
        return 'qux'
ShellCommand(command=['echo', DetermineFoo()])

or, more practically,

from buildbot.interfaces import IRenderable
from zope.interface import implementer
from buildbot.plugins import util

class Now(object):
    def getRenderingFor(self, props):
        return time.clock()
ShellCommand(command=['make', util.Interpolate('TIME=%(kw:now)s', now=Now())])

This is equivalent to:

from buildbot.plugins import util

def now(props):
    return time.clock()
ShellCommand(command=['make', util.Interpolate('TIME=%(kw:now)s', now=now)])

Note that a custom renderable must be instantiated (and its constructor can take whatever arguments you’d like), whereas a function decorated with renderer can be used directly.

URL for build

Its common to need to use the URL for the build in a step. For this you can use a special custom renderer as following:

from buildbot.plugins import *

ShellCommand(command=['make', util.Interpolate('BUILDURL=%(kw:url)s', url=util.URLForBuild)])

2.5.10. Build Steps

BuildSteps are usually specified in the buildmaster’s configuration file, in a list that goes into the BuildFactory. The BuildStep instances in this list are used as templates to construct new independent copies for each build (so that state can be kept on the BuildStep in one build without affecting a later build). Each BuildFactory can be created with a list of steps, or the factory can be created empty and then steps added to it using the addStep method:

from buildbot.plugins import util, steps

f = util.BuildFactory()
    steps.ShellCommand(command=["make", "all"]),
    steps.ShellCommand(command=["make", "test"])

The basic behavior for a BuildStep is to:

  • run for a while, then stop
  • possibly invoke some RemoteCommands on the attached worker
  • possibly produce a set of log files
  • finish with a status described by one of four values defined in buildbot.status.builderSUCCESSWARNINGSFAILURESKIPPED
  • provide a list of short strings to describe the step

The rest of this section describes all the standard BuildStep objects available for use in a Build, and the parameters which can be used to control each. A full list of build steps is available in the Build Step Index. Common Parameters

All BuildSteps accept some common parameters. Some of these control how their individual status affects the overall build. Others are used to specify which Locks (see Interlocks) should be acquired before allowing the step to run.

Arguments common to all BuildStep subclasses:

the name used to describe the step on the status display. Since 0.9.8, this argument might be renderable.
if True, a FAILURE of this build step will cause the build to halt immediately. Steps with alwaysRun=True are still run. Generally speaking, haltOnFailure implies flunkOnFailure (the default for most BuildSteps). In some cases, particularly series of tests, it makes sense to haltOnFailure if something fails early on but not flunkOnFailure. This can be achieved with haltOnFailure=TrueflunkOnFailure=False.
when True, a WARNINGS or FAILURE of this build step will mark the overall build as FAILURE. The remaining steps will still be executed.
when True, a FAILURE of this build step will mark the overall build as a FAILURE. The remaining steps will still be executed.
when True, a WARNINGS or FAILURE of this build step will mark the overall build as having WARNINGS. The remaining steps will still be executed.
when True, a FAILURE of this build step will mark the overall build as having WARNINGS. The remaining steps will still be executed.
if True, this build step will always be run, even if a previous buildstep with haltOnFailure=True has failed.
This will be used to describe the command (on the Waterfall display) while the command is still running. It should be a single imperfect-tense verb, like compiling or testing. The preferred form is a single, short string, but for historical reasons a list of strings is also acceptable.

This will be used to describe the command once it has finished. A simple noun like compile or tests should be used. Like description, this may either be a string or a list of short strings.

If neither description nor descriptionDone are set, the actual command arguments will be used to construct the description. This may be a bit too wide to fit comfortably on the Waterfall display.

All subclasses of BuildStep will contain the description attributes. Consequently, you could add a ShellCommand step like so:

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "test"],

This is an optional suffix appended to the end of the description (ie, after description and descriptionDone). This can be used to distinguish between build steps that would display the same descriptions in the waterfall. This parameter may be a string, a list of short strings or None.

For example, a builder might use the Compile step to build two different codebases. The descriptionSuffix could be set to projectFoo and projectBar, respectively for each step, which will result in the full descriptions compiling projectFoo and compiling projectBar to be shown in the waterfall.

A step can be configured to only run under certain conditions. To do this, set the step’s doStepIfto a boolean value, or to a function that returns a boolean value or Deferred. If the value or function result is false, then the step will return SKIPPED without doing anything. Otherwise, the step will be executed normally. If you set doStepIf to a function, that function should accept one parameter, which will be the Step object itself.

A step can be optionally hidden from the waterfall and build details web pages. To do this, set the step’s hideStepIf to a boolean value, or to a function that takes two parameters – the results and the BuildStep – and returns a boolean value. Steps are always shown while they execute, however after the step has finished, this parameter is evaluated (if a function) and if the value is True, the step is hidden. For example, in order to hide the step if the step has been skipped:

factory.addStep(Foo(..., hideStepIf=lambda results, s: results==SKIPPED))
a list of Locks (instances of buildbot.locks.WorkerLock or buildbot.locks.MasterLock) that should be acquired before starting this BuildStep. Alternatively this could be a renderable that returns this list during build execution. This lets you defer picking the locks to acquire until the build step is about to start running. The Locks will be released when the step is complete. Note that this is a list of actual Lock instances, not names. Also note that all Locks must have unique names. See Interlocks.
The character encoding to use to decode logs produced during the execution of this step. This overrides the default logEncoding; see Log Handling.

The policy to use to propagate the step summary to the build summary. If False, the build summary will never include step summary If True, the build summary will always include step summary If set to a list (e.g. [FAILURE, EXCEPTION]), it will propagate if the step results id is present in that list. If not set or None, the default is computed according to other BuildStep parameters using following algorithm:

self.updateBuildSummaryPolicy = [EXCEPTION, RETRY, CANCELLED]
if self.flunkOnFailure or self.haltOnFailure or self.warnOnFailure:
if self.warnOnWarnings or self.flunkOnWarnings:

Note that in a custom step, if BuildStep.getResultSummary is overridden and setting the buildsummary, updateBuildSummaryPolicy is ignored and build summary will be used regardless. Source Checkout


Support for the old worker-side source checkout steps was removed in Buildbot-0.9.0.

The old source steps used to be imported like this:

from buildbot.steps.source.oldsource import Git

... Git ...


from buildbot.steps.source import Git

while new source steps are in separate Python modules for each version-control system and, using the plugin infrastructure are available as:

from buildbot.plugins import steps

... steps.Git ...
Common Parameters of source checkout operations

All source checkout steps accept some common parameters to control how they get the sources and where they should be placed. The remaining per-VC-system parameters are mostly to specify where exactly the sources are coming from.

mode method

These two parameters specify the means by which the source is checked out. modespecifies the type of checkout and method tells about the way to implement it.

from buildbot.plugins import steps

factory = BuildFactory()
factory.addStep(steps.Mercurial(repourl='path/to/repo', mode='full',

The mode parameter a string describing the kind of VC operation that is desired, defaulting to incremental. The options are

Update the source to the desired revision, but do not remove any other files generated by previous builds. This allows compilers to take advantage of object files from previous builds. This mode is exactly same as the old update mode.
Update the source, but delete remnants of previous builds. Build steps that follow will need to regenerate all object files.

Methods are specific to the version-control system in question, as they may take advantage of special behaviors in that version-control system that can make checkouts more efficient or reliable.

like all Steps, this indicates the directory where the build will take place. Source Steps are special in that they perform some operations outside of the workdir (like creating the workdir itself).
if True, bypass the usual behavior of checking out the revision in the source stamp, and always update to the latest revision in the repository instead. If the specific VC system supports branches and a specific branch is specified in the step parameters via branch or defaultBranch parameters then the latest revision on that branch is checked out.
If set, this specifies a tuple of (delay, repeats) which means that when a full VC checkout fails, it should be retried up to repeats times, waiting delay seconds between attempts. If you don’t provide this, it defaults to None, which means VC operations should not be retried. This is provided to make life easier for workers which are stuck behind poor network connections.

The name of this parameter might vary depending on the Source step you are running. The concept explained here is common to all steps and applies to repourl as well as for baseURL (when applicable).

A common idiom is to pass Property('repository', 'url://default/repo/path') as repository. This grabs the repository from the source stamp of the build. This can be a security issue, if you allow force builds from the web, or have the WebStatus change hooks enabled; as the worker will download code from an arbitrary repository.

This specifies which codebase the source step should use to select the right source stamp. The default codebase value is ''. The codebase must correspond to a codebase assigned by the codebaseGenerator. If there is no codebaseGenerator defined in the master then codebase doesn’t need to be set, the default value will then match all changes.
Specifies the timeout for worker-side operations, in seconds. If your repositories are particularly large, then you may need to increase this value from its default of 1200 (20 minutes).
If this option is true (the default), then the step’s logfile will describe the environment variables on the worker. In situations where the environment is not relevant and is long, it may be easier to set logEnviron=False.
a dictionary of environment strings which will be added to the child command’s environment. The usual property interpolations can be used in environment variable names and values - see Properties.
class buildbot.steps.source.mercurial.Mercurial

The Mercurial build step performs a Mercurial (aka hg) checkout or update.

Branches are available in two modes: dirname, where the name of the branch is a suffix of the name of the repository, or inrepo, which uses Hg’s named-branches support. Make sure this setting matches your changehook, if you have that installed.

from buildbot.plugins import steps

factory.addStep(steps.Mercurial(repourl='path/to/repo', mode='full',
                                method='fresh', branchType='inrepo'))

The Mercurial step takes the following arguments:

where the Mercurial source repository is available.
this specifies the name of the branch to use when a Build does not provide one of its own. This will be appended to repourl to create the string that will be passed to the hg clone command. If alwaysUseLatest is True then the branch and revision information that comes with the Build is ignored and branch specified in this parameter is used.
either ‘dirname’ (default) or ‘inrepo’ depending on whether the branch name should be appended to the repourl or the branch is a Mercurial named branch and can be found within the repourl.
boolean, defaults to True. If set and using inrepos branches, clobber the tree at each branch change. Otherwise, just update to the branch.

mode method

Mercurial’s incremental mode does not require a method. The full mode has three methods defined:

It removes the build directory entirely then makes full clone from repo. This can be slow as it need to clone whole repository
This remove all other files except those tracked by VCS. First it does hg purge --allthen pull/update
All the files which are tracked by Mercurial and listed ignore files are not deleted. Remaining all other files will be deleted before pull/update. This is equivalent to hg purge then pull/update.
class buildbot.steps.source.git.Git

The Git build step clones or updates a Git repository and checks out the specified branch or revision.


The Buildbot supports Git version 1.2.0 and later: earlier versions (such as the one shipped in Ubuntu ‘Dapper’) do not support the git init command that the Buildbot uses.

from buildbot.plugins import steps

factory.addStep(steps.Git(repourl='git://path/to/repo', mode='full',
                          method='clobber', submodules=True))

The Git step takes the following arguments:

repourl (required)
The URL of the upstream Git repository.
branch (optional)
This specifies the name of the branch or the tag to use when a Build does not provide one of its own. If this parameter is not specified, and the Build does not provide a branch, the default branch of the remote repository will be used. If alwaysUseLatest is True then the branch and revision information that comes with the Build is ignored and branch specified in this parameter is used.
submodules (optional, default: False)
When initializing/updating a Git repository, this tells Buildbot whether to handle Git submodules.
shallow (optional)
Instructs Git to attempt shallow clones (--depth 1). The depth defaults to 1 and can be changed by passing an integer instead of True. This option can be used only in full builds with clobber method.
reference (optional)
Use the specified string as a path to a reference repository on the local machine. Git will try to grab objects from this path first instead of the main repository, if they exist.
origin (optional)
By default, any clone will use the name “origin” as the remote repository (eg, “origin/master”). This renderable option allows that to be configured to an alternate name.
progress (optional)
Passes the (--progress) flag to (git fetch). This solves issues of long fetches being killed due to lack of output, but requires Git 1.7.2 or later.
retryFetch (optional, default: False)
If true, if the git fetch fails then Buildbot retries to fetch again instead of failing the entire source checkout.
clobberOnFailure (optional, default: False)
If a fetch or full clone fails we can checkout source removing everything. This way new repository will be cloned. If retry fails it fails the source checkout step.
mode (optional, default: 'incremental')

Specifies whether to clean the build tree or not.

The source is update, but any built files are left untouched.
The build tree is clean of any built files. The exact method for doing this is controlled by the method argument.
method (optional, default: fresh when mode is full)

Git’s incremental mode does not require a method. The full mode has four methods defined:

It removes the build directory entirely then makes full clone from repo. This can be slow as it need to clone whole repository. To make faster clones enable shallow option. If shallow options is enabled and build request have unknown revision value, then this step fails.
This remove all other files except those tracked by Git. First it does git clean -d -f -f -x then fetch/checkout to a specified revision(if any). This option is equal to update mode with ignore_ignores=True in old steps.
All the files which are tracked by Git and listed ignore files are not deleted. Remaining all other files will be deleted before fetch/checkout. This is equivalent to git clean -d -f -f then fetch. This is equivalent to ignore_ignores=False in old steps.
This first checkout source into source directory then copy the source directory to builddirectory then performs the build operation in the copied directory. This way we make fresh builds with very less bandwidth to download source. The behavior of source checkout follows exactly same as incremental. It performs all the incremental checkout behavior in source directory.
getDescription (optional)

After checkout, invoke a git describe on the revision and save the result in a property; the property’s name is either commit-description or commit-description-foo, depending on whether the codebase argument was also provided. The argument should either be a bool or dict, and will change how git describe is called:

  • getDescription=False: disables this feature explicitly

  • getDescription=True or empty dict(): Run git describe with no args

  • getDescription={...}: a dict with keys named the same as the Git option. Each key’s value can be False or None to explicitly skip that argument.

    For the following keys, a value of True appends the same-named Git argument:

    • all : –all
    • always–always
    • contains–contains
    • debug–debug
    • long–long`
    • exact-match–exact-match
    • tags–tags
    • dirty–dirty

    For the following keys, an integer or string value (depending on what Git expects) will set the argument’s parameter appropriately. Examples show the key-value pair:

    • match=foo–match foo
    • abbrev=7–abbrev=7
    • candidates=7–candidates=7
    • dirty=foo–dirty=foo
config (optional)
A dict of Git configuration settings to pass to the remote Git commands.
sshPrivateKey (optional)
The private key to use when running Git for fetch operations. The ssh utility must be in the system path in order to use this option. On Windows only Git distribution that embeds MINGW has been tested (as of July 2017 the official distribution is MINGW-based). The worker must either have the host in the known hosts file or the host key must be specified via the sshHostKey option.
sshHostKey (optional)
Specifies public host key to match when authenticating with SSH public key authentication. This may be either a Secret or just a string. sshPrivateKey must be specified in order to use this option. The host key must be in the form of <key type> <base64-encoded string>, e.g. ssh-rsa AAAAB3N<…>FAaQ==.
class buildbot.steps.source.svn.SVN

The SVN build step performs a Subversion checkout or update. There are two basic ways of setting up the checkout step, depending upon whether you are using multiple branches or not.

The SVN step should be created with the repourl argument:

(required): this specifies the URL argument that will be given to the svn checkout command. It dictates both where the repository is located and which sub-tree should be extracted. One way to specify the branch is to use Interpolate. For example, if you wanted to check out the trunk repository, you could use repourl=Interpolate(""). Alternatively, if you are using a remote Subversion repository which is accessible through HTTP at a URL of, and you wanted to check out the trunk/calc sub-tree, you would directly use repourl="" as an argument to your SVN step.

If you are building from multiple branches, then you should create the SVN step with the repourl and provide branch information with Interpolate:

from buildbot.plugins import steps, util


Alternatively, the repourl argument can be used to create the SVN step without Interpolate:

from buildbot.plugins import steps

(optional): if specified, this will be passed to the svn binary with a --username option.
(optional): if specified, this will be passed to the svn binary with a --password option.
(optional): if specified, an array of strings that will be passed as extra arguments to the svn binary.
(optional): specific files or directories to keep between purges, like some build outputs that can be reused between builds.

(optional): Specify depth argument to achieve sparse checkout. Only available if worker has Subversion 1.5 or higher.

If set to empty updates will not pull in any files or subdirectories not already present. If set to files, updates will pull in any files not already present, but not directories. If set to immediates, updates will pull in any files or subdirectories not already present, the new subdirectories will have depth: empty. If set to infinity, updates will pull in any files or subdirectories not already present; the new subdirectories will have depth-infinity. Infinity is equivalent to SVN default update behavior, without specifying any depth argument.

(optional): By default, the got_revision property is set to the repository’s global revision (“Revision” in the svn info output). Set this parameter to True to have it set to the “Last Changed Rev” instead.

mode method

SVN’s incremental mode does not require a method. The full mode has five methods defined:

It removes the working directory for each build then makes full checkout.
This always always purges local changes before updating. This deletes unversioned files and reverts everything that would appear in a svn status --no-ignore. This is equivalent to the old update mode with always_purge.
This is same as fresh except that it deletes all unversioned files generated by svn status.
This first checkout source into source directory then copy the source directory to builddirectory then performs the build operation in the copied directory. This way we make fresh builds with very less bandwidth to download source. The behavior of source checkout follows exactly same as incremental. It performs all the incremental checkout behavior in source directory.
Similar to method='copy', except using svn export to create build directory so that there are no .svn directories in the build directory.

If you are using branches, you must also make sure your ChangeSource will report the correct branch names.

class buildbot.steps.source.cvs.CVS

The CVS build step performs a CVS checkout or update.

from buildbot.plugins import steps


This step takes the following arguments:

(required): specify the CVSROOT value, which points to a CVS repository, probably on a remote machine. For example, if Buildbot was hosted in CVS then the CVSROOT value you would use to get a copy of the Buildbot source code might be
(required): specify the cvs module, which is generally a subdirectory of the CVSROOT. The cvsmodule for the Buildbot source code is buildbot.
a string which will be used in a -r argument. This is most useful for specifying a branch to work on. Defaults to HEAD. If alwaysUseLatest is True then the branch and revision information that comes with the Build is ignored and branch specified in this parameter is used.
a list of flags to be put before the argument checkout in the CVS command.
a list of flags to be put after the checkout in the CVS command.

mode method

No method is needed for incremental mode. For full mode, method can take the values shown below. If no value is given, it defaults to fresh.

This specifies to remove the workdir and make a full checkout.
This method first runs cvsdisard in the build directory, then updates it. This requires cvsdiscard which is a part of the cvsutil package.
This method is the same as method='fresh', but it runs cvsdiscard --ignore instead of cvsdiscard.
This maintains a source directory for source, which it updates copies to the build directory. This allows Buildbot to start with a fresh directory, without downloading the entire repository on every build.
Password to use while performing login to the remote CVS server. Default is None meaning that no login needs to be performed.
class buildbot.steps.source.bzr.Bzr

bzr is a descendant of Arch/Baz, and is frequently referred to as simply Bazaar. The repository-vs-workspace model is similar to Darcs, but it uses a strictly linear sequence of revisions (one history per branch) like Arch. Branches are put in subdirectories. This makes it look very much like Mercurial.

from buildbot.plugins import steps


The step takes the following arguments:

(required unless baseURL is provided): the URL at which the Bzr source repository is available.
(required unless repourl is provided): the base repository URL, to which a branch name will be appended. It should probably end in a slash.
(allowed if and only if baseURL is provided): this specifies the name of the branch to use when a Build does not provide one of its own. This will be appended to baseURL to create the string that will be passed to the bzr checkout command. If alwaysUseLatest is True then the branch and revision information that comes with the Build is ignored and branch specified in this parameter is used.

mode method

No method is needed for incremental mode. For full mode, method can take the values shown below. If no value is given, it defaults to fresh.

This specifies to remove the workdir and make a full checkout.
This method first runs bzr clean-tree to remove all the unversioned files then updatethe repo. This remove all unversioned files including those in .bzrignore.
This is same as fresh except that it doesn’t remove the files mentioned in .bzrginorei.e, by running bzr clean-tree --ignore.
A local bzr repository is maintained and the repo is copied to build directory for each build. Before each build the local bzr repo is updated then copied to build for next steps.
class buildbot.steps.source.p4.P4

The P4 build step creates a Perforce client specification and performs an update.

from buildbot.plugins import steps, util


You can specify the client spec in two different ways. You can use the p4basep4branch, and (optionally) p4extra_views to build up the viewspec, or you can utilize the p4viewspec to specify the whole viewspec as a set of tuples.

Using p4viewspec will allow you to add lines such as:

//depot/branch/mybranch/...             //<p4client>/...
-//depot/branch/mybranch/notthisdir/... //<p4client>/notthisdir/...

If you specify p4viewspec and any of p4basep4branch, and/or p4extra_views you will receive a configuration error exception.

A view into the Perforce depot without branch name or trailing /.... Typically //depot/proj.
(optional): A single string, which is appended to the p4base as follows <p4base>/<p4branch>/... to form the first line in the viewspec
(optional): a list of (depotpath, clientpath) tuples containing extra views to be mapped into the client specification. Both will have /... appended automatically. The client name and source directory will be prepended to the client path.

This will override any p4branch, p4base, and/or p4extra_views specified. The viewspec will be an array of tuples as follows:


It yields a viewspec with just:

//depot/main/... //<p4client>/...

(optional): The p4viewspec lets you customize the client spec for a builder but, as the previous example shows, it automatically adds ... at the end of each line. If you need to also specify file-level remappings, you can set the p4viewspec_suffix to None so that nothing is added to your viewspec:

[('//depot/main/...', '...'),
 ('-//depot/main/config.xml', 'config.xml'),
 ('//depot/main/config.vancouver.xml', 'config.xml')]

It yields a viewspec with:

//depot/main/...                  //<p4client>/...
-//depot/main/config.xml          //<p4client/main/config.xml
//depot/main/config.vancouver.xml //<p4client>/main/config.xml

Note how, with p4viewspec_suffix set to None, you need to manually add ... where you need it.

(optional): By default, clients are created with the allwrite rmdir options. This string lets you change that.
(optional): the host:port string describing how to get to the P4 Depot (repository), used as the option -p argument for all p4 commands.
(optional): the Perforce user, used as the option -u argument to all p4 commands.
(optional): the Perforce password, used as the option -p argument to all p4 commands.
(optional): The name of the client to use. In mode='full' and mode='incremental', it’s particularly important that a unique name is used for each checkout directory to avoid incorrect synchronization. For this reason, Python percent substitution will be performed on this value to replace %(prop:workername)s with the worker name and %(prop:buildername)s with the builder name. The default is buildbot_%(prop:workername)s_%(prop:buildername)s.
(optional): The type of line ending handling P4 should use. This is added directly to the client spec’s LineEnd property. The default is local.

(optional): Extra arguments to be added to the P4 command-line for the sync command. So for instance if you want to sync only to populate a Perforce proxy (without actually syncing files to disk), you can do:

P4(p4extra_args=['-Zproxyload'], ...)
Set to True to use ticket-based authentication, instead of passwords (but you still need to specify p4passwd).
class buildbot.steps.source.repo.Repo

The Repo build step performs a Repo init and sync.

The Repo step takes the following arguments:

(required): the URL at which the Repo’s manifests source repository is available.
(optional, defaults to master): the manifest repository branch on which repo will take its manifest. Corresponds to the -b argument to the repo init command.
(optional, defaults to default.xml): the manifest filename. Corresponds to the -m argument to the repo init command.

(optional, defaults to None): the repo tarball used for fast bootstrap. If not present the tarball will be created automatically after first sync. It is a copy of the .repo directory which contains all the Git objects. This feature helps to minimize network usage on very big projects with lots of workers.

The suffix of the tarball determines if the tarball is compressed and which compressor is chosen. Supported suffixes are bz2gzlzmalzop, and pigz.

(optional, defaults to None): Number of projects to fetch simultaneously while syncing. Passed to repo sync subcommand with “-j”.
(optional, defaults to False): renderable boolean to control whether repo syncs all branches. I.e. repo sync -c
(optional, defaults to 0): Depth argument passed to repo init. Specifies the amount of git history to store. A depth of 1 is useful for shallow clones. This can save considerable disk space on very large projects.
(optional, defaults to “one week”): renderable to control the policy of updating of the tarball given properties. Returns: max age of tarball in seconds, or None, if we want to skip tarball update. The default value should be good trade off on size of the tarball, and update frequency compared to cost of tarball creation

(optional, defaults to None): list of repo download commands to perform at the end of the Repo step each string in the list will be prefixed repo download, and run as is. This means you can include parameter in the string. For example:

  • ["-c project 1234/4"] will cherry-pick patchset 4 of patch 1234 in project project
  • ["-f project 1234/4"] will enforce fast-forward on patchset 4 of patch 1234 in project project
class buildbot.steps.source.repo.RepoDownloadsFromProperties

util.repo.DownloadsFromProperties can be used as a renderable of the repoDownload parameter it will look in passed properties for string with following possible format:

  • repo download project change_number/patchset_number
  • project change_number/patchset_number
  • project/change_number/patchset_number

All of these properties will be translated into a repo download. This feature allows integrators to build with several pending interdependent changes, which at the moment cannot be described properly in Gerrit, and can only be described by humans.

class buildbot.steps.source.repo.RepoDownloadsFromChangeSource

util.repo.DownloadsFromChangeSource can be used as a renderable of the repoDownload parameter

This rendereable integrates with GerritChangeSource, and will automatically use the repo downloadcommand of repo to download the additional changes introduced by a pending changeset.


You can use the two above Rendereable in conjunction by using the class

For example:

from buildbot.plugins import steps, util

class buildbot.steps.source.gerrit.Gerrit

Gerrit step is exactly like the Git step, except that it integrates with GerritChangeSource, and will automatically checkout the additional changes.

Gerrit integration can be also triggered using forced build with property named gerrit_change with values in format change_number/patchset_number. This property will be translated into a branch name. This feature allows integrators to build with several pending interdependent changes, which at the moment cannot be described properly in Gerrit, and can only be described by humans.

class buildbot.steps.source.github.GitHub

GitHub step is exactly like the Git step, except that it will ignore the revision sent by GitHub change hook, and rather take the branch if the branch ends with /merge.

This allows to test github pull requests merged directly into the mainline.

GitHub indeed provides refs/origin/pull/NNN/merge on top of refs/origin/pull/NNN/head which is a magic ref that always create a merge commit to the latest version of the mainline (i.e. the target branch for the pull request).

The revision in the GitHub event points to /head is important for the GitHub reporter as this is the revision that will be tagged with a CI status when the build is finished.

If you want to use Trigger to create sub tests and want to have the GitHub reporter still update the original revision, make sure you set updateSourceStamp=False in the Trigger configuration.

class buildbot.steps.source.gitlab.GitLab

GitLab step is exactly like the Git step, except that it uses the source repo and branch sent by the GitLab change hook when processing merge requests.

When configuring builders, you can use a ChangeFilter with category = "push" to select normal commits, and category = "merge_request" to select merge requests.

See master/docs/examples/gitlab.cfg in the Buildbot distribution for a tutorial example of integrating Buildbot with GitLab.


Your build worker will need access to the source project of the changeset, or it won’t be able to check out the source. This means authenticating the build worker via ssh credentials in the usual way, then granting it access [via a GitLab deploy key or GitLab project membership]( This needs to be done not only for the main git repo, but also for each fork that wants to be able to submit merge requests against the main repo.

class buildbot.steps.source.darcs.Darcs

The Darcs build step performs a Darcs checkout or update.

from buildbot.plugins import steps

                            mode='full', method='clobber', retry=(10, 1)))

Darcs step takes the following arguments:

(required): The URL at which the Darcs source repository is available.


(optional): defaults to 'incremental'. Specifies whether to clean the build tree or not.

The source is update, but any built files are left untouched.
The build tree is clean of any built files. The exact method for doing this is controlled by the method argument.

(optional): defaults to copy when mode is full. Darcs’ incremental mode does not require a method. The full mode has two methods defined:

It removes the working directory for each build then makes full checkout.
This first checkout source into source directory then copy the source directory to builddirectory then performs the build operation in the copied directory. This way we make fresh builds with very less bandwidth to download source. The behavior of source checkout follows exactly same as incremental. It performs all the incremental checkout behavior in source directory.

The Monotone build step performs a Monotone checkout or update.

from buildbot.plugins import steps

                               mode='full', method='clobber',
                               branch='', retry=(10, 1)))

Monotone step takes the following arguments:

the URL at which the Monotone source repository is available.
this specifies the name of the branch to use when a Build does not provide one of its own. If alwaysUseLatest is True then the branch and revision information that comes with the Build is ignored and branch specified in this parameter is used.
this is a boolean that has a pull from the repository use --ticker=dot instead of the default --ticker=none.


(optional): defaults to 'incremental'. Specifies whether to clean the build tree or not. In any case, the worker first pulls from the given remote repository to synchronize (or possibly initialize) its local database. The mode and method only affect how the build tree is checked-out or updated from the local database.

The source is update, but any built files are left untouched.
The build tree is clean of any built files. The exact method for doing this is controlled by the method argument. Even in this mode, the revisions already pulled remain in the database and a fresh pull is rarely needed.


(optional): defaults to copy when mode is full. Monotone’s incremental mode does not require a method. The full mode has four methods defined:

It removes the build directory entirely then makes fresh checkout from the database.
This remove all other files except those tracked and ignored by Monotone. It will remove all the files that appear in mtn ls unknown. Then it will pull from remote and update the working directory.
This remove all other files except those tracked by Monotone. It will remove all the files that appear in mtn ls ignored and mtn ls unknows. Then pull and update similar to clean
This first checkout source into source directory then copy the source directory to builddirectory then performs the build operation in the copied directory. This way we make fresh builds with very less bandwidth to download source. The behavior of source checkout follows exactly same as incremental. It performs all the incremental checkout behavior in source directory. Other Source operations

Currently the only non-checkout step that is related to version control is GitPush.

class buildbot.steps.source.git.GitPush

The GitPush build step pushes new commits to a Git repository.

The GitPush step takes the following arguments:

(required) The path to the local repository to push commits from.
(required) The URL of the upstream Git repository.
(required) The branch to push. The branch should already exist on the local repository.
(optional) If True, forces overwrite of refs on the remote repository. Corresponds to the --forceflag of the git push command.
(optional) If this option is true (the default), then the step’s logfile will describe the environment variables on the worker. In situations where the environment is not relevant and is long, it may be easier to set logEnviron=False.
(optional) A dictionary of environment strings which will be added to the child command’s environment. The usual property interpolations can be used in environment variable names and values - see Properties.
(optional) Specifies the timeout for worker-side operations, in seconds. If your repositories are particularly large, then you may need to increase this value from its default of 1200 (20 minutes).


(optional) A dict of git configuration settings to pass to the remote git commands.


(optional) The private key to use when running git for fetch operations. The ssh utility must be in the system path in order to use this option. On Windows only git distribution that embeds MINGW has been tested (as of July 2017 the official distribution is MINGW-based). The worker must either have the host in the known hosts file or the host key must be specified via the sshHostKey option.


(optional) Specifies public host key to match when authenticating with SSH public key authentication. This may be either a Secret or just a string. sshPrivateKey must be specified in order to use this option. The host key must be in the form of <key type> <base64-encodedstring>, e.g. ssh-rsa AAAAB3N<...>FAaQ==. ShellCommand

Most interesting steps involve executing a process of some sort on the worker. The ShellCommand class handles this activity.

Several subclasses of ShellCommand are provided as starting points for common build steps.

Using ShellCommands

This is a useful base class for just about everything you might want to do during a build (except for the initial source checkout). It runs a single command in a child shell on the worker. All stdout/stderr is recorded into a LogFile. The step usually finishes with a status of FAILURE if the command’s exit code is non-zero, otherwise it has a status of SUCCESS.

The preferred way to specify the command is with a list of argv strings, since this allows for spaces in filenames and avoids doing any fragile shell-escaping. You can also specify the command with a single string, in which case the string is given to /bin/sh -c COMMAND for parsing.

On Windows, commands are run via cmd.exe /c which works well. However, if you’re running a batch file, the error level does not get propagated correctly unless you add ‘call’ before your batch file’s name: cmd=['call', 'myfile.bat', ...].

The ShellCommand arguments are:


a list of strings (preferred) or single string (discouraged) which specifies the command to be run. A list of strings is preferred because it can be used directly as an argv array. Using a single string (with embedded spaces) requires the worker to pass the string to /bin/sh for interpretation, which raises all sorts of difficult questions about how to escape or interpret shell metacharacters.

If command contains nested lists (for example, from a properties substitution), then that list will be flattened before it is executed.


All ShellCommands are run by default in the workdir, which defaults to the build subdirectory of the worker builder’s base directory. The absolute path of the workdir will thus be the worker’s basedir (set as an option to buildbot-worker create-workerCreating a worker) plus the builder’s basedir (set in the builder’s builddir key in master.cfg) plus the workdir itself (a class-level attribute of the BuildFactory, defaults to build).

For example:

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "test"],

a dictionary of environment strings which will be added to the child command’s environment. For example, to run tests with a different i18n language setting, you might use:

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "test"],
                             env={'LANG': 'fr_FR'}))

These variable settings will override any existing ones in the worker’s environment or the environment specified in the Builder. The exception is PYTHONPATH, which is merged with (actually prepended to) any existing PYTHONPATH setting. The following example will prepend /home/buildbot/lib/python to any existing PYTHONPATH:

from buildbot.plugins import steps

              command=["make", "test"],
              env={'PYTHONPATH': "/home/buildbot/lib/python"}))

To avoid the need of concatenating path together in the master config file, if the value is a list, it will be joined together using the right platform dependent separator.

Those variables support expansion so that if you just want to prepend /home/buildbot/bin to the PATH environment variable, you can do it by putting the value ${PATH} at the end of the value like in the example below. Variables that don’t exist on the worker will be replaced by "".

from buildbot.plugins import steps

              command=["make", "test"],
              env={'PATH': ["/home/buildbot/bin",

Note that environment values must be strings (or lists that are turned into strings). In particular, numeric properties such as buildnumber must be substituted using Interpolate.

if False, stdout from the child process is discarded rather than being sent to the buildmaster for inclusion in the step’s LogFile.
like want_stdout but for stderr. Note that commands run through a PTY do not have separate stdout/stderr streams: both are merged into stdout.

Should this command be run in a ptyFalse by default. This option is not available on Windows.

In general, you do not want to use a pseudo-terminal. This is only useful for running commands that require a terminal - for example, testing a command-line application that will only accept passwords read from a terminal. Using a pseudo-terminal brings lots of compatibility problems, and prevents Buildbot from distinguishing the standard error (red) and standard output (black) streams.

In previous versions, the advantage of using a pseudo-terminal was that grandchild processes were more likely to be cleaned up if the build was interrupted or times out. This occurred because using a pseudo-terminal incidentally puts the command into its own process group.

As of Buildbot-0.8.4, all commands are placed in process groups, and thus grandchild processes will be cleaned up properly.


Sometimes commands will log interesting data to a local file, rather than emitting everything to stdout or stderr. For example, Twisted’s trial command (which runs unit tests) only presents summary information to stdout, and puts the rest into a file named _trial_temp/test.log. It is often useful to watch these files as the command runs, rather than using /bin/cat to dump their contents afterwards.

The logfiles= argument allows you to collect data from these secondary logfiles in near-real-time, as the step is running. It accepts a dictionary which maps from a local Log name (which is how the log data is presented in the build results) to either a remote filename (interpreted relative to the build’s working directory), or a dictionary of options. Each named file will be polled on a regular basis (every couple of seconds) as the build runs, and any new text will be sent over to the buildmaster.

If you provide a dictionary of options instead of a string, you must specify the filename key. You can optionally provide a follow key which is a boolean controlling whether a logfile is followed or concatenated in its entirety. Following is appropriate for logfiles to which the build step will append, where the pre-existing contents are not interesting. The default value for follow is False, which gives the same behavior as just providing a string filename.

from buildbot.plugins import steps

                   command=["make", "test"],
                   logfiles={"triallog": "_trial_temp/test.log"}))

The above example will add a log named ‘triallog’ on the master, based on _trial_temp/test.logon the worker.

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "test"],
                                 "triallog": {
                                    "filename": "_trial_temp/test.log",
                                    "follow": True
If set to True, logfiles will be tracked lazily, meaning that they will only be added when and if something is written to them. This can be used to suppress the display of empty or missing log files. The default is False.
if the command fails to produce any output for this many seconds, it is assumed to be locked up and will be killed. This defaults to 1200 seconds. Pass None to disable.
if the command takes longer than this many seconds, it will be killed. This is disabled by default.
If this option is True (the default), then the step’s logfile will describe the environment variables on the worker. In situations where the environment is not relevant and is long, it may be easier to set logEnviron=False.
If the command should be interrupted (either by buildmaster or timeout etc.), what signal should be sent to the process, specified by name. By default this is “KILL” (9). Specify “TERM” (15) to give the process a chance to cleanup. This functionality requires a 0.8.6 worker or newer.


If set, when interrupting, try to kill the command with SIGTERM and wait for sigtermTime seconds before firing interuptSignal. If None, interruptSignal will be fired immediately on interrupt.

If the command expects input on stdin, that can be supplied a a string with this parameter. This value should not be excessively large, as it is handled as a single string throughout Buildbot – for example, do not pass the contents of a tarball with this parameter.
This is a dictionary that decodes exit codes into results value. For example, {0:SUCCESS,1:FAILURE,2:WARNINGS}, will treat the exit code 2 as WARNINGS. The default is to treat just 0 as successful. ({0:SUCCESS}) any exit code not present in the dictionary will be treated as FAILURE
Shell Sequence

Some steps have a specific purpose, but require multiple shell commands to implement them. For example, a build is often configure; make; make install. We have two ways to handle that:

  • Create one shell command with all these. To put the logs of each commands in separate logfiles, we need to re-write the script as configure 1> configure_log; ... and to add these configure_log files as logfiles argument of the buildstep. This has the drawback of complicating the shell script, and making it harder to maintain as the logfile name is put in different places.
  • Create three ShellCommand instances, but this loads the build UI unnecessarily.

ShellSequence is a class to execute not one but a sequence of shell commands during a build. It takes as argument a renderable, or list of commands which are ShellArg objects. Each such object represents a shell invocation.

The single ShellSequence argument aside from the common parameters is:


A list of ShellArg objects or a renderable the returns a list of ShellArg objects.

from buildbot.plugins import steps, util

        util.ShellArg(command=['make'], logfile='make'),
        util.ShellArg(command=['make', 'check_warning'], logfile='warning', warnOnFailure=True),
        util.ShellArg(command=['make', 'install'], logfile='make install')

All these commands share the same configuration of environmentworkdir and pty usage that can be setup the same way as in ShellCommand.

class buildbot.steps.shellsequence.ShellArg(selfcommand=Nonelogfile=NonehaltOnFailure=FalseflunkOnWarnings=FalseflunkOnFailure=FalsewarnOnWarnings=FalsewarnOnFailure=False)
  • command – (see the ShellCommand command argument),
  • logfile – optional log file name, used as the stdio log of the command

The haltOnFailureflunkOnWarningsflunkOnFailurewarnOnWarningswarnOnFailure parameters drive the execution of the sequence, the same way steps are scheduled in the build. They have the same default values as for buildsteps - see Common Parameters.

Any of the arguments to this class can be renderable.

Note that if logfile name does not start with the prefix stdio, that prefix will be set like stdio<logfile>.

The two ShellSequence methods below tune the behavior of how the list of shell commands are executed, and can be overridden in subclasses.

class buildbot.steps.shellsequence.ShellSequence
Parameters: oneCmd – a string or a list of strings, as rendered from a ShellArginstance’s command argument.

Determine whether the command oneCmd should be executed. If shouldRunTheCommand returns False, the result of the command will be recorded as SKIPPED. The default methods skips all empty strings and empty lists.


Return the status text of the step in the end. The default value is to set the text describing the execution of the last shell command.

Parameters: commands – list of shell args

This method actually runs the shell sequence. The default run method calls runShellSequence, but subclasses can override run to perform other operations, if desired.


This is intended to handle the ./configure step from autoconf-style projects, or the perl Makefile.PLstep from perl modules. The default command is ./configure but you can change this by providing a command= parameter. The arguments are identical to ShellCommand.

from buildbot.plugins import steps

class buildbot.steps.cmake.CMake

This is intended to handle the cmake step for projects that use CMake-based build systems.


Links below point to the latest CMake documentation. Make sure that you check the documentation for the CMake you use.

In addition to the parameters ShellCommand supports, this step accepts the following parameters:

Either a path to a source directory to (re-)generate a build system for it in the current working directory. Or an existing build directory to re-generate its build system.
A build system generator. See cmake-generators(7) for available options.
A dictionary that contains parameters that will be converted to -D{name}={value} when passed to CMake. A renderable which renders to a dictionary can also be provided, see Properties. Refer to cmake(1) for more information.
A list or a tuple that contains options that will be passed to CMake as is. A renderable which renders to a tuple or list can also be provided, see Properties. Refer to cmake(1) for more information.
Path to the CMake binary. Default is cmake
from buildbot.plugins import steps


            'CMAKE_BUILD_TYPE': Property('BUILD_TYPE')


This is meant to handle compiling or building a project written in C. The default command is make all. When the compilation is finished, the log file is scanned for GCC warning messages, a summary log is created with any problems that were seen, and the step is marked as WARNINGS if any were discovered. Through the WarningCountingShellCommand superclass, the number of warnings is stored in a Build Property named warnings-count, which is accumulated over all Compile steps (so if two warnings are found in one step, and three are found in another step, the overall build will have a warnings-count property of 5). Each step can be optionally given a maximum number of warnings via the maxWarnCount parameter. If this limit is exceeded, the step will be marked as a failure.

The default regular expression used to detect a warning is '.*warning[: ].*' , which is fairly liberal and may cause false-positives. To use a different regexp, provide a warningPattern= argument, or use a subclass which sets the warningPattern attribute:

from buildbot.plugins import steps

f.addStep(steps.Compile(command=["make", "test"],
                        warningPattern="^Warning: "))

The warningPattern= can also be a pre-compiled Python regexp object: this makes it possible to add flags like re.I (to use case-insensitive matching).

Note that the compiled warningPattern will have its match method called, which is subtly different from a search. Your regular expression must match the from the beginning of the line. This means that to look for the word “warning” in the middle of a line, you will need to prepend '.*' to your regular expression.

The suppressionFile= argument can be specified as the (relative) path of a file inside the workdir defining warnings to be suppressed from the warning counting and log file. The file will be uploaded to the master from the worker before compiling, and any warning matched by a line in the suppression file will be ignored. This is useful to accept certain warnings (e.g. in some special module of the source tree or in cases where the compiler is being particularly stupid), yet still be able to easily detect and fix the introduction of new warnings.

The file must contain one line per pattern of warnings to ignore. Empty lines and lines beginning with # are ignored. Other lines must consist of a regexp matching the file name, followed by a colon (:), followed by a regexp matching the text of the warning. Optionally this may be followed by another colon and a line number range. For example:

# Sample warning suppression file

mi_packrec.c : .*result of 32-bit shift implicitly converted to 64 bits.* : 560-600
DictTabInfo.cpp : .*invalid access to non-static.*
kernel_types.h : .*only defines private constructors and has no friends.* : 51

If no line number range is specified, the pattern matches the whole file; if only one number is given it matches only on that line.

The suppressionList= argument can be specified as a list of four-tuples as addition or instead of suppressionFile=. The tuple should be [ FILE-RE, WARNING-RE, START, END ]. If FILE-RE is None, then the suppression applies to any file. START and END can be specified as in suppression file, or None.

The default warningPattern regexp only matches the warning text, so line numbers and file names are ignored. To enable line number and file name matching, provide a different regexp and provide a function (callable) as the argument of warningExtractor=. The function is called with three arguments: the BuildStep object, the line in the log file with the warning, and the SRE_Match object of the regexp search for warningPattern. It should return a tuple (filename, linenumber, warning_test). For example:

                  warningPattern="^(.\*?):([0-9]+): [Ww]arning: (.\*)$",

(Compile.warnExtractFromRegexpGroups is a pre-defined function that returns the filename, linenumber, and text from groups (1,2,3) of the regexp match).

In projects with source files in multiple directories, it is possible to get full path names for file names matched in the suppression file, as long as the build command outputs the names of directories as they are entered into and left again. For this, specify regexps for the arguments directoryEnterPattern= and directoryLeavePattern=. The directoryEnterPattern= regexp should return the name of the directory entered into in the first matched group. The defaults, which are suitable for GNU Make, are these:

directoryEnterPattern="make.*: Entering directory [\"`'](.*)['`\"]"
directoryLeavePattern="make.*: Leaving directory"

(TODO: this step needs to be extended to look for GCC error messages as well, and collect them into a separate logfile, along with the source code filenames involved).

Visual C++

These steps are meant to handle compilation using Microsoft compilers. VC++ 6-141 (aka Visual Studio 2003-2015 and VCExpress9) are supported via calling devenv. Msbuild as well as Windows Driver Kit 8 are supported via the MsBuild4MsBuild12MsBuild14 and MsBuild141 steps. These steps will take care of setting up a clean compilation environment, parsing the generated output in real time, and delivering as detailed as possible information about the compilation executed.

All of the classes are in buildbot.steps.vstudio. The available classes are:

  • VC6
  • VC7
  • VC8
  • VC9
  • VC10
  • VC11
  • VC12
  • VC14
  • VC141
  • VS2003
  • VS2005
  • VS2008
  • VS2010
  • VS2012
  • VS2013
  • VS2015
  • VS2017
  • VCExpress9
  • MsBuild4
  • MsBuild12
  • MsBuild14
  • MsBuild141

The available constructor arguments are

The mode default to rebuild, which means that first all the remaining object files will be cleaned by the compiler. The alternate values are build, where only the updated files will be recompiled, and clean, where the current build files are removed and no compilation occurs.
This is a mandatory argument which specifies the project file to be used during the compilation.
This argument defaults to release an gives to the compiler the configuration to use.
This is the place where the compiler is installed. The default value is compiler specific and is the default place where the compiler is installed.
This boolean parameter, defaulting to False instruct the compiler to use its own settings or the one defined through the environment variables PATHINCLUDE, and LIB. If any of the INCLUDE or LIBparameter is defined, this parameter automatically switches to True.
This is a list of path to be added to the PATH environment variable. The default value is the one defined in the compiler options.
This is a list of path where the compiler will first look for include files. Then comes the default paths defined in the compiler options.
This is a list of path where the compiler will first look for libraries. Then comes the default path defined in the compiler options.
That one is only available with the class VS2005 (VC8). It gives the target architecture of the built artifact. It defaults to x86 and does not apply to MsBuild4 or MsBuild12. Please see platform below.
This gives the specific project to build from within a workspace. It defaults to building all projects. This is useful for building cmake generate projects.
This is a mandatory argument for MsBuild4 and MsBuild12 specifying the target platform such as ‘Win32’, ‘x64’ or ‘Vista Debug’. The last one is an example of driver targets that appear once Windows Driver Kit 8 is installed.

Here is an example on how to drive compilation with Visual Studio 2013:

from buildbot.plugins import steps

    steps.VS2013(projectfile="project.sln", config="release",
        arch="x64", mode="build",

Here is a similar example using “MsBuild12”:

from buildbot.plugins import steps

# Build one project in Release mode for Win32
    steps.MsBuild12(projectfile="trunk.sln", config="Release", platform="Win32",

# Build the entire solution in Debug mode for x64
    steps.MsBuild12(projectfile="trunk.sln", config='Debug', platform='x64',

This step runs cppcheck, analyse its output, and set the outcome in Properties.

from buildbot.plugins import steps

f.addStep(steps.Cppcheck(enable=['all'], inconclusive=True]))

This class adds the following arguments:

(Optional, default to cppcheck) Use this if you need to give the full path to the cppcheck binary or if your binary is called differently.
(Optional, default to ['.']) This is the list of paths for the sources to be checked by this step.
(Optional) Use this to give a list of the message classes that should be in cppcheck report. See the cppcheck man page for more information.
(Optional) Set this to True if you want cppcheck to also report inconclusive results. See the cppcheck man page for more information.
(Optional) This is the list of extra arguments to be given to the cppcheck command.

All other arguments are identical to ShellCommand.

class buildbot.steps.mswin.Robocopy

This step runs robocopy on Windows.

Robocopy is available in versions of Windows starting with Windows Vista and Windows Server 2008. For previous versions of Windows, it’s available as part of the Windows Server 2003 Resource Kit Tools.

from buildbot.plugins import steps, util

        description='Deploying binaries...',
        descriptionDone='Deployed binaries.',

Available constructor arguments are:

The path to the source directory (mandatory).
The path to the destination directory (mandatory).
An array of file names or patterns to copy.
Copy files and directories recursively (/E parameter).
Mirror the source directory in the destination directory, including removing files that don’t exist anymore (/MIR parameter).
Delete the source directory after the copy is complete (/MOVE parameter).
An array of file names or patterns to exclude from the copy (/XF parameter).
An array of directory names or patterns to exclude from the copy (/XD parameter).
An array of custom parameters to pass directly to the robocopy command.
Whether to output verbose information (/V /TS /FP parameters).

Note that parameters /TEE /NP will always be appended to the command to signify, respectively, to output logging to the console, use Unicode logging, and not print any percentage progress information for each file.

from buildbot.plugins import steps


This is meant to handle unit tests. The default command is make test, and the warnOnFailure flag is set. The other arguments are identical to ShellCommand.

from buildbot.plugins import steps


This is a simple command that uses the du tool to measure the size of the code tree. It puts the size (as a count of 1024-byte blocks, aka ‘KiB’ or ‘kibibytes’) on the step’s status text, and sets a build property named tree-size-KiB with the same value. All arguments are identical to ShellCommand.

from buildbot.plugins import steps


This is a simple command that knows how to run tests of perl modules. It parses the output to determine the number of tests passed and failed and total number executed, saving the results for later query. The command is prove --lib lib -r t, although this can be overridden with the commandargument. All other arguments are identical to those for ShellCommand.

MTR (mysql-test-run)

The MTR class is a subclass of Test. It is used to run test suites using the mysql-test-run program, as used in MySQL, Drizzle, MariaDB, and MySQL storage engine plugins.

The shell command to run the test suite is specified in the same way as for the Test class. The MTRclass will parse the output of running the test suite, and use the count of tests executed so far to provide more accurate completion time estimates. Any test failures that occur during the test are summarized on the Waterfall Display.

Server error logs are added as additional log files, useful to debug test failures.

Optionally, data about the test run and any test failures can be inserted into a database for further analysis and report generation. To use this facility, create an instance of twisted.enterprise.adbapi.ConnectionPool with connections to the database. The necessary tables can be created automatically by setting autoCreateTables to True, or manually using the SQL found in the source file.

One problem with specifying a database is that each reload of the configuration will get a new instance of ConnectionPool (even if the connection parameters are the same). To avoid that Buildbot thinks the builder configuration has changed because of this, use the steps.mtrlogobserver.EqConnectionPool subclass of ConnectionPool, which implements an equality operation that avoids this problem.

Example use:

from buildbot.plugins import steps, util

myPool = util.EqConnectionPool("MySQLdb", "host", "buildbot", "password", "db")
myFactory.addStep(steps.MTR(workdir="mysql-test", dbpool=myPool,
                            command=["perl", "", "--force"]))

The MTR step’s arguments are:

Maximum number of test failures to show on the waterfall page (to not flood the page in case of a large number of test failures. Defaults to 5.
Maximum length of test names to show unabbreviated in the waterfall page, to avoid excessive column width. Defaults to 16.
Value of option –parallel option used for (number of processes used to run the test suite in parallel). Defaults to 4. This is used to determine the number of server error log files to download from the worker. Specifying a too high value does not hurt (as nonexistent error logs will be ignored), however if using option –parallel value greater than the default it needs to be specified, or some server error logs will be missing.
An instance of twisted.enterprise.adbapi.ConnectionPool, or None. Defaults to None. If specified, results are inserted into the database using the ConnectionPool.
Boolean, defaults to False. If True (and dbpool is specified), the necessary database tables will be created automatically if they do not exist already. Alternatively, the tables can be created manually from the SQL statements found in the source file.
Short string that will be inserted into the database in the row for the test run. Defaults to the empty string, but can be specified to identify different types of test runs.
Descriptive string that will be inserted into the database in the row for the test run. Defaults to the empty string, but can be specified as a user-readable description of this particular test run.
The subdirectory in which to look for server error log files. Defaults to mysql-test, which is usually correct. Interpolate is supported.
class buildbot.steps.subunit.SubunitShellCommand

This buildstep is similar to ShellCommand, except that it runs the log content through a subunit filter to extract test and failure counts.

from buildbot.plugins import steps

f.addStep(steps.SubunitShellCommand(command="make test"))

This runs make test and filters it through subunit. The ‘tests’ and ‘test failed’ progress metrics will now accumulate test data from the test run.

If failureOnNoTests is True, this step will fail if no test is run. By default failureOnNoTests is False. Worker Filesystem Steps

Here are some buildsteps for manipulating the worker’s filesystem.


This step will assert that a given file exists, failing if it does not. The filename can be specified with a property.

from buildbot.plugins import steps


This step requires worker version 0.8.4 or later.


This command copies a directory on the worker.

from buildbot.plugins import steps

f.addStep(steps.CopyDirectory(src="build/data", dest="tmp/data"))

This step requires worker version 0.8.5 or later.

The CopyDirectory step takes the following arguments:

if the copy command fails to produce any output for this many seconds, it is assumed to be locked up and will be killed. This defaults to 120 seconds. Pass None to disable.
if the command takes longer than this many seconds, it will be killed. This is disabled by default.

This command recursively deletes a directory on the worker.

from buildbot.plugins import steps


This step requires worker version 0.8.4 or later.


This command creates a directory on the worker.

from buildbot.plugins import steps


This step requires worker version 0.8.5 or later. Python BuildSteps

Here are some BuildSteps that are specifically useful for projects implemented in Python.

class buildbot.steps.python.BuildEPYDoc

epydoc is a tool for generating API documentation for Python modules from their docstrings. It reads all the .py files from your source tree, processes the docstrings therein, and creates a large tree of .html files (or a single .pdf file).

The BuildEPYDoc step will run epydoc to produce this API documentation, and will count the errors and warnings from its output.

You must supply the command line to be used. The default is make epydocs, which assumes that your project has a Makefile with an epydocs target. You might wish to use something like epydoc -o apirefsource/PKGNAME instead. You might also want to add option –pdf to generate a PDF file instead of a large tree of HTML files.

The API docs are generated in-place in the build tree (under the workdir, in the subdirectory controlled by the option -o argument). To make them useful, you will probably have to copy them to somewhere they can be read. For example if you have server with configured nginx web server, you can place generated docs to it’s public folder with command like rsync -ad apiref/ You might instead want to bundle them into a tarball and publish it in the same place where the generated install tarball is placed.

from buildbot.plugins import steps

f.addStep(steps.BuildEPYDoc(command=["epydoc", "-o", "apiref", "source/mypkg"]))
class buildbot.steps.python.PyFlakes

PyFlakes is a tool to perform basic static analysis of Python code to look for simple errors, like missing imports and references of undefined names. It is like a fast and simple form of the C lintprogram. Other tools (like pychecker) provide more detailed results but take longer to run.

The PyFlakes step will run pyflakes and count the various kinds of errors and warnings it detects.

You must supply the command line to be used. The default is make pyflakes, which assumes you have a top-level Makefile with a pyflakes target. You might want to use something like pyflakes . or pyflakes src.

from buildbot.plugins import steps

f.addStep(steps.PyFlakes(command=["pyflakes", "src"]))
class buildbot.steps.python.Sphinx

Sphinx is the Python Documentation Generator. It uses RestructuredText as input format.

The Sphinx step will run sphinx-build or any other program specified in its sphinx argument and count the various warnings and error it detects.

from buildbot.plugins import steps


This step takes the following arguments:

(required) Name of the directory where the documentation will be generated.
(optional, defaulting to .), Name the directory where the file will be found
(optional) Indicates the builder to use.
(optional, defaulting to sphinx-build) Indicates the executable to run.
(optional) List of tags to pass to sphinx-build
(optional) Dictionary of defines to overwrite values of the file.
(optional) String, one of full or incremental (the default). If set to full, indicates to Sphinx to rebuild everything without re-using the previous build results.

Similarly, the PyLint step will run pylint and analyze the results.

You must supply the command line to be used. There is no default.

from buildbot.plugins import steps

f.addStep(steps.PyLint(command=["pylint", "src"]))
class buildbot.steps.python_twisted.Trial

This step runs a unit test suite using trial, a unittest-like testing framework that is a component of Twisted Python. Trial is used to implement Twisted’s own unit tests, and is the unittest-framework of choice for many projects that use Twisted internally.

Projects that use trial typically have all their test cases in a ‘test’ subdirectory of their top-level library directory. For example, for a package petmail, the tests might be in petmail/test/test_*.py. More complicated packages (like Twisted itself) may have multiple test directories, like twisted/test/test_*.py for the core functionality and twisted/mail/test/test_*.py for the email-specific tests.

To run trial tests manually, you run the trial executable and tell it where the test cases are located. The most common way of doing this is with a module name. For petmail, this might look like trial petmail.test, which would locate all the test_*.py files under petmail/test/, running every test case it could find in them. Unlike the that comes with Python, it is not necessary to run the as a script; you always let trial do the importing and running. The step’s tests` parameter controls which tests trial will run: it can be a string or a list of strings.

To find the test cases, the Python search path must allow something like import petmail.test to work. For packages that don’t use a separate top-level lib directory, PYTHONPATH=. will work, and will use the test cases (and the code they are testing) in-place. PYTHONPATH=build/lib or PYTHONPATH=build/lib.somearch are also useful when you do a python build step first. The testpath attribute of this class controls what PYTHONPATH is set to before running trial.

Trial has the ability, through the --testmodule flag, to run only the set of test cases named by special test-case-name tags in source files. We can get the list of changed source files from our parent Build and provide them to trial, thus running the minimal set of test cases needed to cover the Changes. This is useful for quick builds, especially in trees with a lot of test cases. The testChanges parameter controls this feature: if set, it will override tests.

The trial executable itself is typically just trial, and is typically found in the shell search path. It can be overridden with the trial parameter. This is useful for Twisted’s own unittests, which want to use the copy of bin/trial that comes with the sources.

To influence the version of Python being used for the tests, or to add flags to the command, set the python parameter. This can be a string (like python2.2) or a list (like ['python2.3', '-Wall']).

Trial creates and switches into a directory named _trial_temp/ before running the tests, and sends the twisted log (which includes all exceptions) to a file named test.log. This file will be pulled up to the master where it can be seen as part of the status output.

from buildbot.plugins import steps


Trial has the ability to run tests on several workers in parallel (beginning with Twisted 12.3.0). Set jobsto the number of workers you want to run. Note that running trial in this way will create multiple log files (named test.N.logerr.N.log and out.N.log starting with N=0) rather than a single test.log.

This step takes the following arguments:

(optional) Number of worker-resident trial workers to use when running the tests. Defaults to 1 worker. Only works with Twisted>=12.3.0.
class buildbot.steps.python_twisted.RemovePYCs

This is a simple built-in step that will remove .pyc files from the workdir. This is useful in builds that update their source (and thus do not automatically delete .pyc files) but where some part of the build process is dynamically searching for Python modules. Notably, trial has a bad habit of finding old test modules.

from buildbot.plugins import steps

f.addStep(steps.RemovePYCs()) Transferring Files
class buildbot.steps.transfer.FileUpload
class buildbot.steps.transfer.FileDownload

Most of the work involved in a build will take place on the worker. But occasionally it is useful to do some work on the buildmaster side. The most basic way to involve the buildmaster is simply to move a file from the worker to the master, or vice versa. There are a pair of steps named FileUpload and FileDownload to provide this functionality. FileUpload moves a file up to the master, while FileDownloadmoves a file down from the master.

As an example, let’s assume that there is a step which produces an HTML file within the source tree that contains some sort of generated project documentation. And let’s assume that we run nginx web server on buildmaster host for serving static files. We want to move this file to the buildmaster, into a /usr/share/nginx/www/ directory, so it can be visible to developers. This file will wind up in the worker-side working directory under the name docs/reference.html. We want to put it into the master-side /usr/share/nginx/www/ref.html, and add a link to the HTML status to the uploaded file.

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "docs"]))

The masterdest= argument will be passed to os.path.expanduser, so things like ~ will be expanded properly. Non-absolute paths will be interpreted relative to the buildmaster’s base directory. Likewise, the workersrc= argument will be expanded and interpreted relative to the builder’s working directory.


The copied file will have the same permissions on the master as on the worker, look at the mode=parameter to set it differently.

To move a file from the master to the worker, use the FileDownload command. For example, let’s assume that some step requires a configuration file that, for whatever reason, could not be recorded in the source code repository or generated on the worker side:

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "config"]))

Like FileUpload, the mastersrc= argument is interpreted relative to the buildmaster’s base directory, and the workerdest= argument is relative to the builder’s working directory. If the worker is running in ~worker, and the builder’s builddir is something like tests-i386, then the workdir is going to be ~worker/tests-i386/build, and a workerdest= of foo/bar.html will get put in ~worker/tests-i386/build/foo/bar.html. Both of these commands will create any missing intervening directories.

Other Parameters

The maxsize= argument lets you set a maximum size for the file to be transferred. This may help to avoid surprises: transferring a 100MB coredump when you were expecting to move a 10kB status file might take an awfully long time. The blocksize= argument controls how the file is sent over the network: larger blocksizes are slightly more efficient but also consume more memory on each end, and there is a hard-coded limit of about 640kB.

The mode= argument allows you to control the access permissions of the target file, traditionally expressed as an octal integer. The most common value is probably 0755, which sets the x executable bit on the file (useful for shell scripts and the like). The default value for mode= is None, which means the permission bits will default to whatever the umask of the writing process is. The default umask tends to be fairly restrictive, but at least on the worker you can make it less restrictive with a --umaskcommand-line option at creation time (Worker Options).

The keepstamp= argument is a boolean that, when True, forces the modified and accessed time of the destination file to match the times of the source file. When False (the default), the modified and accessed times of the destination file are set to the current time on the buildmaster.

The url= argument allows you to specify an url that will be displayed in the HTML status. The title of the url will be the name of the item transferred (directory for DirectoryUpload or file for FileUpload). This allows the user to add a link to the uploaded item if that one is uploaded to an accessible place.

For FileUpload, the urlText= argument allows you to specify the url title that will be displayed in the web UI.

Transferring Directories
class buildbot.steps.transfer.DirectoryUpload

To transfer complete directories from the worker to the master, there is a BuildStep named DirectoryUpload. It works like FileUpload, just for directories. However it does not support the maxsizeblocksize and mode arguments. As an example, let’s assume an generated project documentation, which consists of many files (like the output of doxygen or epydoc). And let’s assume that we run nginx web server on buildmaster host for serving static files. We want to move the entire documentation to the buildmaster, into a /usr/share/nginx/www/docs directory, and add a link to the uploaded documentation on the HTML status page. On the worker-side the directory can be found under docs:

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "docs"]))

The DirectoryUpload step will create all necessary directories and transfers empty directories, too.

The maxsize and blocksize parameters are the same as for FileUpload, although note that the size of the transferred data is implementation-dependent, and probably much larger than you expect due to the encoding used (currently tar).

The optional compress argument can be given as 'gz' or 'bz2' to compress the datastream.


The permissions on the copied files will be the same on the master as originally on the worker, see option buildbot-worker create-worker --umask to change the default one.

Transferring Multiple Files At Once
class buildbot.steps.transfer.MultipleFileUpload

In addition to the FileUpload and DirectoryUpload steps there is the MultipleFileUpload step for uploading a bunch of files (and directories) in a single BuildStep. The step supports all arguments that are supported by FileUpload and DirectoryUpload, but instead of a the single workersrc parameter it takes a (plural) workersrcs parameter. This parameter should either be a list, something that can be rendered as a list or a string which will be converted to a list. Additionally it supports the globparameter if this parameter is set to True all arguments in workersrcs will be parsed through glob and the results will be uploaded to masterdest.:

from buildbot.plugins import steps

f.addStep(steps.ShellCommand(command=["make", "test"]))
f.addStep(steps.ShellCommand(command=["make", "docs"]))
f.addStep(steps.MultipleFileUpload(workersrcs=["docs", "test-results.html"],

The url= parameter, can be used to specify a link to be displayed in the HTML status of the step.

The way URLs are added to the step can be customized by extending the MultipleFileUpload class. The allUploadsDone method is called after all files have been uploaded and sets the URL. The uploadDonemethod is called once for each uploaded file and can be used to create file-specific links.

import os

from buildbot.plugins import steps

class CustomFileUpload(steps.MultipleFileUpload):
    linkTypes = ('.html', '.txt')

    def linkFile(self, basename):
        name, ext = os.path.splitext(basename)
        return ext in self.linkTypes

    def uploadDone(self, result, source, masterdest):
        if self.url:
            basename = os.path.basename(source)
            if self.linkFile(basename):
                self.addURL(self.url + '/' + basename, basename)

    def allUploadsDone(self, result, sources, masterdest):
        if self.url:
            notLinked = [src for src in sources if not self.linkFile(src)]
            numFiles = len(notLinked)
            if numFiles:
                self.addURL(self.url, '... %d more' % numFiles) Transferring Strings
class buildbot.steps.transfer.StringDownload
class buildbot.steps.transfer.JSONStringDownload
class buildbot.steps.transfer.JSONPropertiesDownload

Sometimes it is useful to transfer a calculated value from the master to the worker. Instead of having to create a temporary file and then use FileDownload, you can use one of the string download steps.

from buildbot.plugins import steps, util


StringDownload works just like FileDownload except it takes a single argument, s, representing the string to download instead of a mastersrc argument.

from buildbot.plugins import steps

buildinfo = {
    'branch': Property('branch'),
    'got_revision': Property('got_revision')
f.addStep(steps.JSONStringDownload(buildinfo, workerdest="buildinfo.json"))

JSONStringDownload is similar, except it takes an o argument, which must be JSON serializable, and transfers that as a JSON-encoded string to the worker.

from buildbot.plugins import steps


JSONPropertiesDownload transfers a json-encoded string that represents a dictionary where properties maps to a dictionary of build property name to property value; and sourcestamp represents the build’s sourcestamp. Running Commands on the Master
class buildbot.steps.master.MasterShellCommand

Occasionally, it is useful to execute some task on the master, for example to create a directory, deploy a build result, or trigger some other centralized processing. This is possible, in a limited fashion, with the MasterShellCommand step.

This step operates similarly to a regular ShellCommand, but executes on the master, instead of the worker. To be clear, the enclosing Build object must still have a worker object, just as for any other step – only, in this step, the worker does not do anything.

In this example, the step renames a tarball based on the day of the week.

from buildbot.plugins import steps

    command="mv widgetsoft-new.tar.gz widgetsoft-`date +%a`.tar.gz",


By default, this step passes a copy of the buildmaster’s environment variables to the subprocess. To pass an explicit environment instead, add an env={..} argument.

Environment variables constructed using the env argument support expansion so that if you just want to prepend /home/buildbot/bin to the PATH environment variable, you can do it by putting the value ${PATH} at the end of the value like in the example below. Variables that don’t exist on the master will be replaced by "".

from buildbot.plugins import steps

              command=["make", "www"],
              env={'PATH': ["/home/buildbot/bin",

Note that environment values must be strings (or lists that are turned into strings). In particular, numeric properties such as buildnumber must be substituted using Interpolate.

(optional) The directory from which the command will be ran.
(optional) Signal to use to end the process, if the step is interrupted.
class buildbot.steps.master.LogRenderable

This build step takes content which can be renderable and logs it in a pretty-printed format. It can be useful for debugging properties during a build.

class buildbot.steps.master.Assert

This build step takes a Renderable or constant passed in as first argument. It will test if the expression evaluates to True and succeed the step or fail the step otherwise. Setting Properties

These steps set properties on the master based on information from the worker.

class buildbot.steps.master.SetProperty

SetProperty takes two arguments of property and value where the value is to be assigned to the property key. It is usually called with the value argument being specified as a Interpolate object which allows the value to be built from other property values:

from buildbot.plugins import steps, util

        value=util.Interpolate("sch=%(prop:scheduler)s, worker=%(prop:workername)s")
SetProperties step
class buildbot.steps.master.SetProperty

SetProperties takes a dictionary to be turned into build properties.

It is similar to SetProperty, and meant to be used with a Renderer function or a dictionary ofInterpolate objects which allows the value to be built from other property values:

"""Example borrowed from Julia's master.cfg (MIT)"""
from buildbot.plugins import *

def compute_artifact_filename(props):
    # Get the output of the `make print-BINARYDIST_FILENAME` step
    reported_filename = props.getProperty('artifact_filename')

    # First, see if we got a BINARYDIST_FILENAME output
    if reported_filename[:26] == "BINARYDIST_FILENAME=":
        local_filename = util.Interpolate(reported_filename[26:].strip()+"%(prop:os_pkg_ext)s")
        # If not, use non-sf/consistent_distnames naming
        if is_mac(props):
            local_filename = util.Interpolate("contrib/mac/app/Julia-%(prop:version)s-%(prop:shortcommit)s.%(prop:os_pkg_ext)s")
        elif is_winnt(props):
            local_filename = util.Interpolate("julia-%(prop:version)s-%(prop:tar_arch)s.%(prop:os_pkg_ext)s")
            local_filename = util.Interpolate("julia-%(prop:shortcommit)s-Linux-%(prop:tar_arch)s.%(prop:os_pkg_ext)s")

    # upload_filename always follows sf/consistent_distname rules
    upload_filename = util.Interpolate("julia-%(prop:shortcommit)s-%(prop:os_name)s%(prop:bits)s.%(prop:os_pkg_ext)s")
    return {
        "local_filename": local_filename
        "upload_filename": upload_filename


This buildstep is similar to ShellCommand, except that it captures the output of the command into a property. It is usually used like this:

from buildbot.plugins import steps

f.addStep(steps.SetPropertyFromCommand(command="uname -a", property="uname"))

This runs uname -a and captures its stdout, stripped of leading and trailing whitespace, in the property uname. To avoid stripping, add strip=False.

The property argument can be specified as a Interpolate object, allowing the property name to be built from other property values.

Passing includeStdout=False (default True) stops capture from stdout.

Passing includeStderr=True (default False) allows capture from stderr.

The more advanced usage allows you to specify a function to extract properties from the command output. Here you can use regular expressions, string interpolation, or whatever you would like. In this form, extract_fn should be passed, and not Property. The extract_fn function is called with three arguments: the exit status of the command, its standard output as a string, and its standard error as a string. It should return a dictionary containing all new properties.

Note that passing in extract_fn will set includeStderr to True.

def glob2list(rc, stdout, stderr):
    jpgs = [l.strip() for l in stdout.split('\n')]
    return {'jpgs': jpgs}

f.addStep(SetPropertyFromCommand(command="ls -1 *.jpg", extract_fn=glob2list))

Note that any ordering relationship of the contents of stdout and stderr is lost. For example, given:

    command="echo output1; echo error >&2; echo output2",

Then my_extract will see stdout="output1\noutput2\n" and stderr="error\n".

Avoid using the extract_fn form of this step with commands that produce a great deal of output, as the output is buffered in memory until complete.

class buildbot.steps.worker.SetPropertiesFromEnv

Buildbot workers (later than version 0.8.3) provide their environment variables to the master on connect. These can be copied into Buildbot properties with the SetPropertiesFromEnv step. Pass a variable or list of variables in the variables parameter, then simply use the values as properties in a later step.

Note that on Windows, environment variables are case-insensitive, but Buildbot property names are case sensitive. The property will have exactly the variable name you specify, even if the underlying environment variable is capitalized differently. If, for example, you use variables=['Tmp'], the result will be a property named Tmp, even though the environment variable is displayed as TMP in the Windows GUI.

from buildbot.plugins import steps, util

f.addStep(steps.SetPropertiesFromEnv(variables=["SOME_JAVA_LIB_HOME", "JAVAC"]))

Note that this step requires that the worker be at least version 0.8.3. For previous versions, no environment variables are available (the worker environment will appear to be empty). Triggering Schedulers
class buildbot.steps.trigger.Trigger

The counterpart to the Triggerable scheduler is the Trigger build step:

from buildbot.plugins import steps

                        set_properties={ 'quick' : False }))

The SourceStamps to use for the triggered build are controlled by the arguments updateSourceStampalwaysUseLatest, and sourceStamps.

Hyperlinks are added to the build detail web pages for each triggered build.


lists the Triggerable schedulers that should be triggered when this step is executed.


It is possible, but not advisable, to create a cycle where a build continually triggers itself, because the schedulers are specified by name.

When waitForFinish is True, all schedulers in this list will not cause the trigger step to fail. unimportantSchedulerNames must be a subset of schedulerNames If waitForFinish is False, unimportantSchedulerNames will simply be ignored.

If True, the step will not finish until all of the builds from the triggered schedulers have finished.

If False (the default) or not given, then the buildstep succeeds immediately after triggering the schedulers.


If True (the default), then step updates the source stamps given to the Triggerable schedulers to include got_revision (the revision actually used in this build) as revision (the revision to use in the triggered builds). This is useful to ensure that all of the builds use exactly the same source stamps, even if other Changes have occurred while the build was running.

If False (and neither of the other arguments are specified), then the exact same SourceStamps are used.

If True, then no SourceStamps are given, corresponding to using the latest revisions of the repositories specified in the Source steps. This is useful if the triggered builds use to a different source repository.
Accepts a list of dictionaries containing the keys branchrevisionrepositoryproject, and optionally patch_levelpatch_bodypatch_subdirpatch_author and patch_comment and creates the corresponding SourceStamps. If only one sourceStamp has to be specified then the argument sourceStamp can be used for a dictionary containing the keys mentioned above. The arguments updateSourceStampalwaysUseLatest, and sourceStamp can be specified using properties.

allows control of the properties that are passed to the triggered scheduler. The parameter takes a dictionary mapping property names to values. You may use Interpolate here to dynamically construct new property values. For the simple case of copying a property, this might look like:

set_properties={"my_prop1" : Property("my_prop1"),
                "my_prop2" : Property("my_prop2")}

where Property is an instance of


The copy_properties parameter, given a list of properties to copy into the new build request, has been deprecated in favor of explicit use of set_properties.

Dynamic Trigger

Sometimes it is desirable to select which scheduler to trigger, and which properties to set dynamically, at the time of the build. For this purpose, Trigger step supports a method that you can customize in order to override statically defined schedulernamesset_properties and optionally unimportant.

Returns: list of dictionaries containing the keys ‘sched_name’, ‘props_to_set’ and ‘unimportant’ optionally via deferred

This method returns a list of dictionaries describing what scheduler to trigger, with which properties and if the scheduler is unimportant. Old style list of tuples is still supported, in which case unimportant is considered False. The properties should already be rendered (ie, concrete value, not objects wrapped by Interpolate or Property). Since this function happens at build-time, the property values are available from the step and can be used to decide what schedulers or properties to use.

With this method, you can also trigger the same scheduler multiple times with different set of properties. The sourcestamp configuration is however the same for each triggered build request. RPM-Related Steps

These steps work with RPMs and spec files.


The RpmBuild step builds RPMs based on a spec file:

from buildbot.plugins import steps

f.addStep(steps.RpmBuild(specfile="proj.spec", dist='.el5'))

The step takes the following parameters

The .spec file to build from
Definition for _topdir, defaulting to the workdir.
Definition for _builddir, defaulting to the workdir.
Definition for _rpmdir, defaulting to the workdir.
Definition for _sourcedir, defaulting to the workdir.
Definition for _srcrpmdir, defaulting to the workdir.
Distribution to build, used as the definition for _dist.
A dictionary of additional definitions to declare.
If true, use the auto-release mechanics.
If true, use the version-control revision mechanics. This uses the got_revision property to determine the revision and define _revision. Note that this will not work with multi-codebase builds.

The RpmLint step checks for common problems in RPM packages or spec files:

from buildbot.plugins import steps


The step takes the following parameters

The file or directory to check. In case of a directory, it is recursively searched for RPMs and spec files to check.
Path to a rpmlint config file. This is passed as the user configuration file if present.
Mock Steps

Mock ( creates chroots and builds packages in them. It populates the changeroot with a basic system and the packages listed as build requirement. The type of chroot to build is specified with the root parameter. To use mock your Buildbot user must be added to the mock group.

MockBuildSRPM Step

The MockBuildSRPM step builds a SourceRPM based on a spec file and optionally a source directory:

from buildbot.plugins import steps

f.addStep(steps.MockBuildSRPM(root='default', spec='mypkg.spec'))

The step takes the following parameters

Use chroot configuration defined in /etc/mock/<root>.cfg.
The directory where the logfiles and the SourceRPM are written to.
Build the SourceRPM from this spec file.
Path to the directory containing the sources, defaulting to ..
MockRebuild Step

The MockRebuild step rebuilds a SourceRPM package:

from buildbot.plugins import steps

f.addStep(steps.MockRebuild(root='default', spec='mypkg-1.0-1.src.rpm'))

The step takes the following parameters

Uses chroot configuration defined in /etc/mock/<root>.cfg.
The directory where the logfiles and the SourceRPM are written to.
The path to the SourceRPM to rebuild. Debian Build Steps

The DebPbuilder step builds Debian packages within a chroot built by pbuilder. It populates the chroot with a basic system and the packages listed as build requirement. The type of the chroot to build is specified with the distributiondistribution and mirror parameter. To use pbuilder your Buildbot user must have the right to run pbuilder as root using sudo.

from buildbot.plugins import steps


The step takes the following parameters

Architecture to build chroot for.
Name, or nickname, of the distribution. Defaults to ‘stable’.
Path of the basetgz to use for building.
URL of the mirror used to download the packages from.
List if packages to install in addition to the base system.
Path to a gpg keyring to verify the downloaded packages. This is necessary if you build for a foreign distribution.
Repos to activate for chroot building.

The DebCowbuilder step is a subclass of DebPbuilder, which use cowbuilder instead of pbuilder.


The DebLintian step checks a build .deb for bugs and policy violations. The packages or changes file to test is specified in fileloc

from buildbot.plugins import steps, util

f.addStep(steps.DebLintian(fileloc=util.Interpolate("%(prop:deb-changes)s"))) Miscellaneous BuildSteps

A number of steps do not fall into any particular category.


The HLint step runs Twisted Lore, a lint-like checker over a set of .xhtml files. Any deviations from recommended style is flagged and put in the output log.

The step looks at the list of changes in the build to determine which files to check - it does not check all files. It specifically excludes any .xhtml files in the top-level sandbox/ directory.

The step takes a single, optional, parameter: python. This specifies the Python executable to use to run Lore.

from buildbot.plugins import steps


MaxQ ( is a web testing tool that allows you to record HTTP sessions and play them back. The MaxQ step runs this framework.

from buildbot.plugins import steps


The single argument, testdir, specifies where the tests should be run. This directory will be passed to the command, and the results analyzed.

HTTP Requests

Using the HTTPStep step, it is possible to perform HTTP requests in order to trigger another REST service about the progress of the build.


This step requires the txrequests and requests Python libraries.

The parameters are the following:

(mandatory) The URL where to send the request
The HTTP method to use (out of POSTGETPUTDELETEHEAD or OPTIONS), default to POST.
Dictionary of URL parameters to append to the URL.
The body to attach the request. If a dictionary is provided, form-encoding will take place.
Dictionary of headers to send.
other params

Any other keywords supported by the requests api can be passed to this step.


The entire Buildbot master process shares a single Requests Session object. This has the advantage of supporting connection re-use and other HTTP/1.1 features. However, it also means that any cookies or other state changed by one step will be visible to other steps, causing unexpected results. This behavior may change in future versions.

When the method is known in advance, class with the name of the method can also be used. In this case, it is not necessary to specify the method.


from buildbot.plugins import steps, util

                     data = {
                        'builder': util.Property('buildername'),
                        'buildnumber': util.Property('buildnumber'),
                        'workername': util.Property('workername'),
                        'revision': util.Property('got_revision')

2.5.11. Interlocks

Until now, we assumed that a master can run builds at any worker whenever needed or desired. Some times, you want to enforce additional constraints on builds. For reasons like limited network bandwidth, old worker machines, or a self-willed data base server, you may want to limit the number of builds (or build steps) that can access a resource. Access Modes

The mechanism used by Buildbot is known as the read/write lock [1]. It allows either many readers or a single writer but not a combination of readers and writers. The general lock has been modified and extended for use in Buildbot. Firstly, the general lock allows an infinite number of readers. In Buildbot, we often want to put an upper limit on the number of readers, for example allowing two out of five possible builds at the same time. To do this, the lock counts the number of active readers. Secondly, the terms read mode and write mode are confusing in Buildbot context. They have been replaced by counting mode (since the lock counts them) and exclusive mode. As a result of these changes, locks in Buildbot allow a number of builds (up to some fixed number) in counting mode, or they allow one build in exclusive mode.


Access modes are specified when a lock is used. That is, it is possible to have a single lock that is used by several workers in counting mode, and several workers in exclusive mode. In fact, this is the strength of the modes: accessing a lock in exclusive mode will prevent all counting-mode accesses. Count

Often, not all workers are equal. To allow for this situation, Buildbot allows to have a separate upper limit on the count for each worker. In this way, you can have at most 3 concurrent builds at a fast worker, 2 at a slightly older worker, and 1 at all other workers. Scope

The final thing you can specify when you introduce a new lock is its scope. Some constraints are global – they must be enforced over all workers. Other constraints are local to each worker. A master lock is used for the global constraints. You can ensure for example that at most one build (of all builds running at all workers) accesses the data base server. With a worker lock you can add a limit local to each worker. With such a lock, you can for example enforce an upper limit to the number of active builds at a worker, like above. Examples

Time for a few examples. Below a master lock is defined to protect a data base, and a worker lock is created to limit the number of builds at each worker.

from buildbot.plugins import util

db_lock = util.MasterLock("database")
build_lock = util.WorkerLock("worker_builds",
                             maxCountForWorker={'fast': 3, 'new': 2})

db_lock is defined to be a master lock. The database string is used for uniquely identifying the lock. At the next line, a worker lock called build_lock is created. It is identified by the worker_builds string. Since the requirements of the lock are a bit more complicated, two optional arguments are also specified. The maxCount parameter sets the default limit for builds in counting mode to 1. For the worker called 'fast' however, we want to have at most three builds, and for the worker called 'new'the upper limit is two builds running at the same time.

The next step is accessing the locks in builds. Buildbot allows a lock to be used during an entire build (from beginning to end), or only during a single build step. In the latter case, the lock is claimed for use just before the step starts, and released again when the step ends. To prevent deadlocks, [2] it is not possible to claim or release locks at other times.

To use locks, you add them with a locks argument to a build or a step. Each use of a lock is either in counting mode (that is, possibly shared with other builds) or in exclusive mode, and this is indicated with the syntax lock.access(mode), where mode is one of "counting" or "exclusive".

A build or build step proceeds only when it has acquired all locks. If a build or step needs a lot of locks, it may be starved [3] by other builds that need fewer locks.

To illustrate use of locks, a few examples.

from buildbot.plugins import util, steps

db_lock = util.MasterLock("database")
build_lock = util.WorkerLock("worker_builds",
                             maxCountForWorker={'fast': 3, 'new': 2})

f = util.BuildFactory()
f.addStep(steps.ShellCommand(command="make all"))
f.addStep(steps.ShellCommand(command="make test",

b1 = {'name': 'full1', 'workername': 'fast',  'builddir': 'f1', 'factory': f,
       'locks': [build_lock.access('counting')] }

b2 = {'name': 'full2', 'workername': 'new',   'builddir': 'f2', 'factory': f,
       'locks': [build_lock.access('counting')] }

b3 = {'name': 'full3', 'workername': 'old',   'builddir': 'f3', 'factory': f,
       'locks': [build_lock.access('counting')] }

b4 = {'name': 'full4', 'workername': 'other', 'builddir': 'f4', 'factory': f,
       'locks': [build_lock.access('counting')] }

c['builders'] = [b1, b2, b3, b4]

Here we have four workers fastnewold, and other. Each worker performs the same checkout, make, and test build step sequence. We want to enforce that at most one test step is executed between all workers due to restrictions with the data base server. This is done by adding the locks= parameter with the third step. It takes a list of locks with their access mode. Alternatively, this can take a renderable that returns an list of locks with their access mode.

In this case only the db_lock is needed. The exclusive access mode is used to ensure there is at most one worker that executes the test step.

In addition to exclusive accessing the data base, we also want workers to stay responsive even under the load of a large number of builds being triggered. For this purpose, the worker lock called build_lock is defined. Since the restraint holds for entire builds, the lock is specified in the builder with 'locks': [build_lock.access('counting')].

Note that you will occasionally see lock.access(mode) written as LockAccess(lock, mode). The two are equivalent, but the former is preferred.

[1] See for more information.
[2] Deadlock is the situation where two or more workers each hold a lock in exclusive mode, and in addition want to claim the lock held by the other worker exclusively as well. Since locks allow at most one exclusive user, both workers will wait forever.
[3] Starving is the situation that only a few locks are available, and they are immediately grabbed by another build. As a result, it may take a long time before all locks needed by the starved build are free at the same time.

2.5.12. Reporters

The Buildmaster has a variety of ways to present build status to various users. Each such delivery method is a Reporter Target object in the configuration’s services list. To add reporter targets, you just append more objects to this list:

c['services'] = []

m = reporters.MailNotifier(fromaddr="buildbot@localhost",

c['services'].append(reporters.IRC(host="", nick="bb",
                                  channels=[{"channel": "#example1"},
                                            {"channel": "#example2",
                                             "password": "somesecretpassword"}]))

Most reporter objects take a tags= argument, which can contain a list of tag names: in this case, it will only show status for Builders that contains the named tags.


Implementation Note

Each of these objects should be a service.BuildbotService which will be attached to the BuildMaster object when the configuration is processed.

The remainder of this section describes each built-in reporters. A full list of reporters is available in the Reporter Target Index. MailNotifier
class buildbot.reporters.mail.MailNotifier

The Buildbot can send email when builds finish. The most common use of this is to tell developers when their change has caused the build to fail. It is also quite common to send a message to a mailing list (usually named builds or similar) about every build.

The MailNotifier reporter is used to accomplish this. You configure it by specifying who mail should be sent to, under what circumstances mail should be sent, and how to deliver the mail. It can be configured to only send out mail for certain builders, and only send messages when the build fails, or when the builder transitions from success to failure. It can also be configured to include various build logs in each message.

If a proper lookup function is configured, the message will be sent to the “interested users” list (Doing Things With Users), which includes all developers who made changes in the build. By default, however, Buildbot does not know how to construct an email addressed based on the information from the version control system. See the lookup argument, below, for more information.

You can add additional, statically-configured, recipients with the extraRecipients argument. You can also add interested users by setting the owners build property to a list of users in the scheduler constructor (Configuring Schedulers).

Each MailNotifier sends mail to a single set of recipients. To send different kinds of mail to different recipients, use multiple MailNotifiers. TODO: or subclass MailNotifier and override getRecipients()

The following simple example will send an email upon the completion of each build, to just those developers whose Changes were included in the build. The email contains a description of the Build, its results, and URLs where more information can be obtained.

from buildbot.plugins import reporters
mn = reporters.MailNotifier(fromaddr="",

To get a simple one-message-per-build (say, for a mailing list), use the following form instead. This form does not send mail to individual developers (and thus does not need the lookup= argument, explained below), instead it only ever sends mail to the extra recipients named in the arguments:

mn = reporters.MailNotifier(fromaddr="",

If your SMTP host requires authentication before it allows you to send emails, this can also be done by specifying smtpUser and smtpPassword:

mn = reporters.MailNotifier(fromaddr="",
                            relayhost="", smtpPort=587,


If for some reasons you are not able to send a notification with TLS enabled and specified user name and password, you might want to use master/contrib/ to see if it works at all.

If you want to require Transport Layer Security (TLS), then you can also set useTls:

mn = reporters.MailNotifier(fromaddr="",
                            useTls=True, relayhost="",
                            smtpPort=587, smtpUser="",


If you see twisted.mail.smtp.TLSRequiredError exceptions in the log while using TLS, this can be due either to the server not supporting TLS or to a missing PyOpenSSL package on the BuildMaster system.

In some cases it is desirable to have different information then what is provided in a standard MailNotifier message. For this purpose MailNotifier provides the argument messageFormatter (an instance of MessageFormatter) which allows for the creation of messages with unique content.

For example, if only short emails are desired (e.g., for delivery to phones):

from buildbot.plugins import reporters
mn = reporters.MailNotifier(fromaddr="",
                            messageFormatter=reporters.MessageFormatter(template="STATUS: {{ summary }}"))

Another example of a function delivering a customized html email is given below:

from buildbot.plugins import reporters

<h4>Build status: {{ summary }}</h4>
<p> Worker used: {{ workername }}</p>
{% for step in build['steps'] %}
<p> {{ step['name'] }}: {{ step['result'] }}</p>
{% endfor %}
<p><b> -- The Buildbot</b></p>

mn = reporters.MailNotifier(fromaddr="",
                                template=template, template_type='html',
                                wantProperties=True, wantSteps=True))
MailNotifier arguments
The email address to be used in the ‘From’ header.
(boolean). If True (the default), send mail to all of the Interested Users. Interested Users are authors of changes and users from the owners build property. Override MailNotifiergetResponsibleUsersForBuild method to change that. If False, only send mail to the extraRecipientslist.
(list of strings). A list of email addresses to which messages should be sent (in addition to the InterestedUsers list, which includes any developers who made Changes that went into this build). It is a good idea to create a small mailing list and deliver to that, then let subscribers come and go as they please.
(string). A string to be used as the subject line of the message. %(builder)s will be replaced with the name of the builder which provoked the message.

Mode is a list of strings; however there are two strings which can be used as shortcuts instead of the full lists. The possible shortcuts are:

Always send mail about builds. Equivalent to (changefailingpassingproblemwarningsexception).
Equivalent to (warningsfailing).

Set these shortcuts as actual strings in the configuration:

from buildbot.plugins import reporters
mn = reporters.MailNotifier(fromaddr="",

(list of strings). A combination of:

Send mail about builds which were cancelled.
Send mail about builds which change status.
Send mail about builds which fail.
Send mail about builds which succeed.
Send mail about a build which failed when the previous build has passed.
Send mail about builds which generate warnings.
Send mail about builds which generate exceptions.

Defaults to (failingpassingwarnings).

(list of strings). A list of builder names for which mail should be sent. Defaults to None (send mail for all builds). Use either builders or tags, but not both.
(list of strings). A list of tag names to serve status information for. Defaults to None (all tags). Use either builders or tags, but not both.
(list of strings). A list of scheduler names to serve status information for. Defaults to None (all schedulers).
(list of strings). A list of branch names to serve status information for. Defaults to None (all branches).
(boolean). If True, include all build logs as attachments to the messages. These can be quite large. This can also be set to a list of log names, to send a subset of the logs. Defaults to False.
(boolean). If True, include the patch content if a patch was present. Patches are usually used on a Try server. Defaults to True.
(boolean). If True, send a single summary email consisting of the concatenation of all build completion messages rather than a completion message for each build. Defaults to False.
(string). The host to which the outbound SMTP connection should be made. Defaults to ‘localhost’
(int). The port that will be used on outbound SMTP connections. Defaults to 25.
(boolean). When this argument is True (default is FalseMailNotifier requires that STARTTLS encryption is used for the connection with the relayhost. Authentication is required for STARTTLS so the arguments smtpUser and smtpPassword must also be specified.
(boolean). When this argument is True (default is FalseMailNotifier connects to relayhost over an encrypted SSL/TLS connection. This configuration is typically used over port 465.
(string). The user name to use when authenticating with the relayhost. Can be a Secret.
(string). The password that will be used when authenticating with the relayhost. Can be a Secret.

(implementer of IEmailLookup). Object which provides IEmailLookup, which is responsible for mapping User names (which come from the VC system) into valid email addresses.

If the argument is not provided, the MailNotifier will attempt to build the sendToInterestedUsersfrom the authors of the Changes that led to the Build via User Objects. If the author of one of the Build’s Changes has an email address stored, it will added to the recipients list. With this method, owners are still added to the recipients. Note that, in the current implementation of user objects, email addresses are not stored; as a result, unless you have specifically added email addresses to the user database, this functionality is unlikely to actually send any emails.

Most of the time you can use a simple Domain instance. As a shortcut, you can pass as string: this will be treated as if you had provided Domain(str). For example, lookup='' will allow mail to be sent to all developers whose SVN usernames match their account names. See master/buildbot/reporters/ for more details.

Regardless of the setting of lookupMailNotifier will also send mail to addresses in the extraRecipients list.

This is an optional instance of the reporters.MessageFormatter class that can be used to generate a custom mail message. This class uses the Jinja2 templating language to generate the body and optionally the subject of the mails. Templates can either be given inline (as string), or read from the filesystem.
(dictionary). A dictionary containing key/value pairs of extra headers to add to sent e-mails. Both the keys and the values may be a Interpolate instance.
This is a list of names of workers, which should be watched. In case a worker get missing, a notification is sent. The value of watchedWorkers can also be set to all (default) or None. You also need to specify email address to which the notification is sent in the worker configuration.
This is an optional instance of the reporters.messageFormatterMissingWorker class that can be used to generate a custom mail message for missing workers. This class uses the Jinja2 templating language to generate the body and optionally the subject of the mails. Templates can either be given inline (as string), or read from the filesystem.
MessageFormatter arguments

The easiest way to use the messageFormatter parameter is to create a new instance of the reporters.MessageFormatter class. The constructor to that class takes the following arguments:

This is the directory that is used to look for the various templates.
This is the name of the file in the template_dir directory that will be used to generate the body of the mail. It defaults to default_mail.txt.
If this parameter is set, this parameter indicates the content of the template used to generate the body of the mail as string.
This indicates the type of the generated template. Use either ‘plain’ (the default) or ‘html’.
This is the name of the file in the template_dir directory that contains the content of the subject of the mail.
Alternatively, this is the content of the subject of the mail as string.

This is an extension of the standard context that will be given to the templates. Use this to add content to the templates that is otherwise not available.

Alternatively, you can subclass MessageFormatter and override the buildAdditionalContext in order to grab more context from the data API.

  • master – the master object
  • ctx – the context dictionary to enhance

optionally deferred

default implementation will add self.ctx into the current template context

This parameter (defaults to True) will extend the content of the given build object with the Properties from the build.
This parameter (defaults to False) will extend the content of the given build object with information about the steps of the build. Use it only when necessary as this increases the overhead in term of CPU and memory on the master.
This parameter (defaults to False) will extend the content of the steps of the given build object with the full Logs of each steps from the build. This requires wantSteps to be True. Use it only when mandatory as this increases the overhead in term of CPU and memory on the master greatly.

As a help to those writing Jinja2 templates the following table describes how to get some useful pieces of information from the various data objects:

Name of the builder that generated this event
{{ buildername }}
Title of the BuildMaster
{{ projects }}
MailNotifier mode
{{ mode }} (a combination of changefailingpassingproblemwarningsexceptionall)
URL to build page
{{ build_url }}
URL to buildbot main page
{{ buildbot_url }}
Status of the build as string.

This require extending the context of the Formatter via the ctx parameter with: ctx=dict(statuses=util.Results).

{{ statuses[results] }}

Build text
{{ build['state_string'] }}
Mapping of property names to (values, source)
{{ build['properties'] }}
For instance the build reason (from a forced build)
{{ build['properties']['reason'][0] }}
Worker name
{{ workername }}
List of responsible users
{{ blamelist | join(', ') }}
MessageFormatterMissingWorkers arguments

The easiest way to use the messageFormatterMissingWorkers parameter is to create a new instance of the reporters.MessageFormatterMissingWorkers class.

The constructor to that class takes the same arguments as MessageFormatter, minus wantLogswantPropertieswantSteps.

The default ctx for the missing worker email is made of:

The buildbot title as per c['title'] from the master.cfg
The buildbot title as per c['title'] from the master.cfg

The worker object as defined in the REST api plus two attributes:

List of emails to be notified for this worker.
String describing the approximate the time of last connection for this worker. Pushover Notifications
class buildbot.reporters.pushover.PushoverNotifier

Apart of sending mail, Buildbot can send Pushover notifications. It can be used by administrators to receive an instant message to an iPhone or an Android device if a build fails. The PushoverNotifierreporter is used to accomplish this. Its configuration is very similar to the mail notifications, however—due to the notification size constrains—the logs and patches cannot be attached.

To use this reporter, you need to generate and application on the Pushover website and provide your user key and the API token.

The following simple example will send a Pushover notification upon the completion of each build. The notification contains a description of the Build, its results, and URLs where more information can be obtained. The user_key and api_token values should be replaced with proper ones obtained from the Pushover website for your application.

from buildbot.plugins import reporters
pn = reporters.PushoverNotifier(user_key="1234", api_token='abcd')

This notifier supports parameters subjectmodebuilderstagsschedulersbranchesbuildSetSummarymessageFormatterwatchedWorkers, and messageFormatterMissingWorker from the mail notifier. See above for their explanation. However, watchedWorkers defaults to None.

The following additional parameters are accepted by this class:

The user key from the Pushover website. It is used to identify the notification recipient. Can be a Secret.
API token for a custom application from the Pushover website. Can be a Secret.
Dictionary of Pushover notification priorities. The keys of the dictionary can be changefailingpassingwarningsexception and are equivalent to the mode strings. The values are integers between -2…2, specifying notification priority. In case a mode is missing from this dictionary, the default value of 0 is used.
Other parameters send to Pushover API. Check for their list. Pushjet Notifications
class buildbot.reporters.pushover.PushjetNotifier

Pushjet is another instant notification service, similar to Pushover. To use this reporter, you need to generate a Pushjet service and provide its secret.

The parameters subjectmodebuilderstagsschedulersbranchesbuildSetSummarymessageFormatterwatchedWorkers, and messageFormatterMissingWorker are common with mail and Pushover notifier.

The Pushjet specific parameters are:

This is a secret token for your Pushjet service. See to learn how to create a new Pushjet service and get its secret token. Can be a Secret.
Dictionary of Pushjet notification levels. The keys of the dictionary can be changefailingpassingwarningsexception and are equivalent to the mode strings. The values are integers between 0…5, specifying notification priority. In case a mode is missing from this dictionary, the default value set by Pushover is used.
Base URL for custom Pushjet instances. Defaults to IRC Bot

The IRC reporter creates an IRC bot which will attach to certain channels and be available for status queries. It can also be asked to announce builds as they occur, or be told to shut up.

The IRC Bot in buildbot nine, is mostly a rewrite, and not all functionality has been ported yet. Patches are very welcome for restoring the full functionality.


Security Note

Please note that any user having access to your irc channel or can PM the bot will be able to create or stop builds bug #3377.

from buildbot.plugins import reporters
irc = reporters.IRC("", "botnickname",
                 channels=[{"channel": "#example1"},
                           {"channel": "#example2",
                            "password": "somesecretpassword"}],
                   'exception': 1,
                   'successToFailure': 1,
                   'failureToSuccess': 1,

The following parameters are accepted by this class:

(mandatory) The IRC server address to connect to.
(mandatory) The name this bot will use on the IRC server.
(mandatory) This is a list of channels to join on the IRC server. Each channel can be a string (e.g. #buildbot), or a dictionary {'channel': '#buildbot', 'password': 'secret'} if each channel requires a different password. A global password can be set with the password parameter.
(optional) This is a list of person to contact on the IRC server.
(optional, default to 6667) The port to connect to on the IRC server.
(optional, disabled by default) This allow user to force builds via this bot.
(optional) When set, this bot will only communicate about builders containing those tags. (tags functionality is not yet ported)
(optional) The global password used to register the bot to the IRC server. If provided, it will be sent to Nickserv to claim the nickname: some IRC servers will not allow clients to send private messages until they have logged in with a password. Can be a Secret.
(optional) A dictionary of events to be notified on the IRC channels. At the moment, irc bot can listen to build ‘start’ and ‘finish’ events. This parameter can be changed during run-time by sending the notify command to the bot.
(optional, disabled by default) Whether to send notices rather than messages when communicating with a channel.
(optional, disabled by default) Whether or not to display the blame list for failed builds. (blame list functionality is not ported yet)
(optional, disabled by default) Whether or not to display the revision leading to the build the messages are about. (useRevisions functionality is not ported yet)
(optional, disabled by default) Whether or not to use SSL when connecting to the IRC server. Note that this option requires PyOpenSSL.
(optional) Delay to wait before reconnecting to the server when the connection has been lost.
(optional) Delay to wait before reconnecting to the IRC server when the connection failed.
(optional, enabled by default) The bot can add color to some of its messages. You might turn it off by setting this parameter to False.
(optional, disabled by default) This allow users to shutdown the master.

To use the service, you address messages at the Buildbot, either normally (botnickname: status) or with private messages (/msg botnickname status). The Buildbot will respond in kind.

If you issue a command that is currently not available, the Buildbot will respond with an error message. If the noticeOnChannel=True option was used, error messages will be sent as channel notices instead of messaging.

Some of the commands currently available:

list builders
Emit a list of all configured builders
status BUILDER
Announce the status of a specific Builder: what it is doing right now.
status all
Announce the status of all Builders
If the given Builder is currently running, wait until the Build is finished and then announce the results.
Return the results of the last build to run on the given Builder.
Join the given IRC channel
Leave the given IRC channel
notify on|off|list EVENT

Report events relating to builds. If the command is issued as a private message, then the report will be sent back as a private message to the user who issued the command. Otherwise, the report will be sent to the channel. Available events to be notified are:

A build has started
A build has finished
A build finished successfully
A build failed
A build generated and exception
The previous build was x, but this one is Y, where x and Y are each one of success, warnings, failure, exception (except Y is capitalized). For example: successToFailure will notify if the previous build was successful, but this one failed
Describe a command. Use help commands to get a list of known commands.
shutdown ARG

Control the shutdown process of the Buildbot master. Available arguments are:

Check if the Buildbot master is running or shutting down
Start clean shutdown
Stop clean shutdown
Shutdown immediately without waiting for the builders to finish
Announce the URL of the Buildbot’s home page.
Announce the version of this Buildbot.

Additionally, the config file may specify default notification options as shown in the example earlier.

If the allowForce=True option was used, some additional commands will be available:

force build [--codebase=CODEBASE] [--branch=BRANCH] [--revision=REVISION] [--props=PROP1=VAL1,PROP2=VAL2...] BUILDER REASON
Tell the given Builder to start a build of the latest code. The user requesting the build and REASONare recorded in the Build status. The Buildbot will announce the build’s status when it finishes.The user can specify a branch and/or revision with the optional parameters --branch=BRANCH and --revision=REVISION. The user can also give a list of properties with --props=PROP1=VAL1,PROP2=VAL2...
Terminate any running build in the given BuilderREASON will be added to the build status to explain why it was stopped. You might use this if you committed a bug, corrected it right away, and don’t want to wait for the first build (which is destined to fail) to complete before starting the second (hopefully fixed) build.

If the tags is set (see the tags option in Builder Configuration) changes related to only builders belonging to those tags of builders will be sent to the channel.

If the useRevisions option is set to True, the IRC bot will send status messages that replace the build number with a list of revisions that are contained in that build. So instead of seeing build #253 of …, you would see something like build containing revisions [a87b2c4]. Revisions that are stored as hashes are shortened to 7 characters in length, as multiple revisions can be contained in one build and may exceed the IRC message length limit.

Two additional arguments can be set to control how fast the IRC bot tries to reconnect when it encounters connection issues. lostDelay is the number of seconds the bot will wait to reconnect when the connection is lost, where as failedDelay is the number of seconds until the bot tries to reconnect when the connection failed. lostDelay defaults to a random number between 1 and 5, while failedDelay defaults to a random one between 45 and 60. Setting random defaults like this means multiple IRC bots are less likely to deny each other by flooding the server. GerritStatusPush
class buildbot.status.status_gerrit.GerritStatusPush

GerritStatusPush sends review of the Change back to the Gerrit server, optionally also sending a message when a build is started. GerritStatusPush can send a separate review for each build that completes, or a single review summarizing the results for all of the builds.

class GerritStatusPush(serverusernamereviewCBstartCBportreviewArgstartArgsummaryCBsummaryArgidentity_filebuildersnotify...)
  • server (string) – Gerrit SSH server’s address to use for push event notifications.
  • username (string) – Gerrit SSH server’s username.
  • identity_file – (optional) Gerrit SSH identity file.
  • port (int) – (optional) Gerrit SSH server’s port (default: 29418)
  • reviewCB – (optional) Called each time a build finishes. Build properties are available. Can be a deferred.
  • reviewArg –

    (optional) argument passed to the review callback.

    If reviewCB callback is specified, it must return a message and optionally labels. If no message is specified, nothing will be sent to Gerrit. It should return a dictionary:

    {'message': message,
     'labels': {label-name: label-score,

    For example:

    def gerritReviewCB(builderName, build, result, master, arg):
        if result == util.RETRY:
            return dict()
        message =  "Buildbot finished compiling your patchset\n"
        message += "on configuration: %s\n" % builderName
        message += "The result is: %s\n" % util.Results[result].upper()
        if arg:
            message += "\nFor more details visit:\n"
            message += build['url'] + "\n"
        if result == util.SUCCESS:
            verified = 1
            verified = -1
        return dict(message=message, labels={'Verified': verified})

    Which require an extra import in the config:

    from buildbot.plugins import util
  • startCB – (optional) Called each time a build is started. Build properties are available. Can be a deferred.
  • startArg –

    (optional) argument passed to the start callback.

    If startCB is specified, it must return a message and optionally labels. If no message is specified, nothing will be sent to Gerrit. It should return a dictionary:

    {'message': message,
     'labels': {label-name: label-score,

    For example:

    def gerritStartCB(builderName, build, arg):
        message = "Buildbot started compiling your patchset\n"
        message += "on configuration: %s\n" % builderName
        message += "See your build here: %s" % build['url']
        return dict(message=message)
  • summaryCB – (optional) Called each time a buildset finishes. Each build in the buildset has properties available. Can be a deferred.
  • summaryArg –

    (optional) argument passed to the summary callback.

    If summaryCB callback is specified, it must return a message and optionally labels. If no message is specified, nothing will be sent to Gerrit. The message and labels should be a summary of all the builds within the buildset. It should return a dictionary:

    {'message': message,
     'labels': {label-name: label-score,

    For example:

    def gerritSummaryCB(buildInfoList, results, status, arg):
        success = False
        failure = False
        msgs = []
        for buildInfo in buildInfoList:
            msg = "Builder %(name)s %(resultText)s (%(text)s)" % buildInfo
            link = buildInfo.get('url', None)
            if link:
                msg += " - " + link
                msg += "."
            if buildInfo['result'] == util.SUCCESS:
                success = True
                failure = True
        if success and not failure:
            verified = 1
            verified = -1
        return dict(message='\n\n'.join(msgs),
                        'Verified': verified
  • builders – (optional) list of builders to send results for. This method allows to filter results for a specific set of builder. By default, or if builders is None, then no filtering is performed.
  • notify – (optional) control who gets notified by Gerrit once the status is posted. The possible values for notify can be found in your version of the Gerrit documentation for the gerrit review command.
  • wantSteps – (optional, defaults to False) Extends the given build object with information about steps of the build. Use it only when necessary as this increases the overhead in term of CPU and memory on the master.
  • wantLogs – (optional, default to False) Extends the steps of the given build object with the full logs of the build. This requires wantSteps to be True. Use it only when mandatory as this increases the overhead in term of CPU and memory on the master greatly.


By default, a single summary review is sent; that is, a default summaryCB is provided, but no reviewCBor startCB.


If reviewCB or summaryCB do not return any labels, only a message will be pushed to the Gerrit server.

See also

master/docs/examples/git_gerrit.cfg and master/docs/examples/repo_gerrit.cfg in the Buildbot distribution provide a full example setup of Git+Gerrit or Repo+Gerrit of GerritStatusPush. HttpStatusPush
from buildbot.plugins import reporters
sp = reporters.HttpStatusPush(serverUrl="")

HttpStatusPush builds on StatusPush and sends HTTP requests to serverUrl, with all the items json-encoded. It is useful to create a status front end outside of Buildbot for better scalability.

It requires either txrequests or treq to be installed to allow interaction with http server.


The json data object sent is completely different from the one that was generated by 0.8.x buildbot. It is indeed generated using data api.

class HttpStatusPush(serverUrluser=Nonepassword=Noneauth=Noneformat_fn=Nonebuilders=NonewantProperties=FalsewantSteps=FalsewantPreviousBuild=FalsewantLogs=False)
  • serverUrl (string) – the url where to do the http post
  • user (string) – the BasicAuth user to post as
  • password (string) – the BasicAuth user’s password (can be a Secret).
  • auth – the authentication method to use. Refer to the documentation of the requests library for more information.
  • format_fn (function) – a function that takes the build as parameter and returns a dictionary to be pushed to the server (as json).
  • builders (list) – only send update for specified builders
  • wantProperties (boolean) – include ‘properties’ in the build dictionary
  • wantSteps (boolean) – include ‘steps’ in the build dictionary
  • wantLogs (boolean) – include ‘logs’ in the steps dictionaries. This needs wantSteps=True. This dumps the full content of logs and may consume lots of memory and CPU depending on the log size.
  • wantPreviousBuild (boolean) – include ‘prev_build’ in the build dictionary
Json object spec

The default json object sent is a build object augmented with some more data as follow.

    "url": "http://yourbot/path/to/build",
    "<build data api values>": "[...]",
    "buildset": "<buildset data api values>",
    "builder": "<builder data api values>",
    "buildrequest": "<buildrequest data api values>"

If you want another format, don’t hesitate to use the format_fn parameter to customize the payload. The build parameter given to that function is of type build, optionally enhanced with properties, steps, and logs information. GitHubStatusPush
class buildbot.reporters.github.GitHubStatusPush
from buildbot.plugins import reporters, util

context = Interpolate("buildbot/%(prop:buildername)s")
gs = reporters.GitHubStatusPush(token='githubAPIToken',
                                startDescription='Build started.',
                                endDescription='Build done.')
factory = util.BuildFactory()
buildbot_bbtools = util.BuilderConfig(

GitHubStatusPush publishes a build status using GitHub Status API.

It requires txrequests package to allow interaction with GitHub REST API.

It is configured with at least a GitHub API token.

You can create a token from you own GitHub - Profile - Applications - Register new application or use an external tool to generate one.

class GitHubStatusPush(tokenstartDescription=NoneendDescription=Nonecontext=NonebaseURL=Noneverbose=Falsebuilders=None)
  • token (string) – token used for authentication. (can be a Secret)
  • string startDescription (rendereable) – Custom start message (default: ‘Build started.’)
  • string endDescription (rendereable) – Custom end message (default: ‘Build done.’)
  • string context (rendereable) – Passed to GitHub to differentiate between statuses. A static string can be passed or Interpolate for dynamic substitution. The default context is buildbot/%(prop:buildername)s.
  • baseURL (string) – specify the github api endpoint if you work with GitHub Enterprise
  • verbose (boolean) – if True, logs a message for each successful status push
  • builders (list) – only send update for specified builders GitHubCommentPush
class buildbot.reporters.github.GitHubCommentPush
from buildbot.plugins import reporters, util

gc = reporters.GitHubCommentPush(token='githubAPIToken',
                                 startDescription='Build started.',
                                 endDescription='Build done.')
factory = util.BuildFactory()
buildbot_bbtools = util.BuilderConfig(

GitHubCommentPush publishes a comment on a PR using GitHub Review Comments API.

It requires txrequests package to allow interaction with GitHub REST API.

It is configured with at least a GitHub API token. By default, it will only comment at the end of a build unless a startDescription is provided.

You can create a token from you own GitHub - Profile - Applications - Register new application or use an external tool to generate one.

class GitHubCommentPush(tokenstartDescription=NoneendDescription=NonebaseURL=Noneverbose=Falsebuilders=None)
  • token (string) – token used for authentication. (can be a Secret)
  • string startDescription (rendereable) – Custom start message (default: None)
  • string endDescription (rendereable) – Custom end message (default: ‘Build done.’)
  • baseURL (string) – specify the github api endpoint if you work with GitHub Enterprise
  • verbose (boolean) – if True, logs a message for each successful status push
  • builders (list) – only send update for specified builders
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • debug (boolean) – logs every requests and their response

string for comment, must be less than 65536 bytes.

Here’s a complete example of posting build results as a github comment:

def getresults(props):
    master = props.master
    steps = yield'builders', props.getProperty('buildername'), 'builds', props.getProperty('buildnumber'), 'steps'))
    for step in steps:
        if step['results'] == util.Results.index('failure'):
            logs = yield"steps", step['stepid'], 'logs'))
            for l in logs:
                all_logs.append('Step : {0} Result : {1}'.format(step['name'], util.Results[step['results']]))
                l['stepname'] = step['name']
                l['content'] = yield"logs", l['logid'], 'contents'))
                step_logs = l['content']['content'].split('\n')
                include = False
                for i, sl in enumerate(step_logs):

gc = GitHubCommentPush(token='githubAPIToken',
c['services'].append(gc) BitbucketServerStatusPush
class buildbot.reporters.BitbucketServer.BitbucketServerStatusPush
from buildbot.plugins import reporters

ss = reporters.BitbucketServerStatusPush('',

BitbucketServerStatusPush publishes build status using BitbucketServer Build Integration REST API. The build status is published to a specific commit SHA in Bitbucket Server. It tracks the last build for each builderName for each commit built.

Specifically, it follows the Updating build status for commits document.

It requires txrequests package to allow interaction with Bitbucket Server REST API.

It uses HTTP Basic AUTH. As a result, we recommend you use https in your base_url rather than http.

class BitbucketServerStatusPush(base_urluserpasswordkey=NonestatusName=NonestartDescription=NoneendDescription=Noneverbose=Falsebuilders=None)
  • base_url (string) – The base url of the Bitbucket Server host, up to and optionally including the first / of the path.
  • user (string) – The Bitbucket Server user to post as. (can be a Secret)
  • password (string) – The Bitbucket Server user’s password. (can be a Secret)
  • string key (renderable) – Passed to Bitbucket Server to differentiate between statuses. A static string can be passed or Interpolate for dynamic substitution. The default key is %(prop:buildername)s.
  • string statusName (renderable) – The name that is displayed for this status. The default name is nothing, so Bitbucket Server will use the key parameter.
  • string startDescription (renderable) – Custom start message (default: ‘Build started.’)
  • string endDescription (renderable) – Custom end message (default: ‘Build done.’)
  • verbose (boolean) – If True, logs a message for each successful status push.
  • builders (list) – Only send update for specified builders.
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • debug (boolean) – logs every requests and their response BitbucketServerPRCommentPush
class buildbot.reporters.BitbucketServer.BitbucketServerPRCommentPush
from buildbot.plugins import reporters

ss = reporters.BitbucketServerPRCommentPush('',

BitbucketServerPRCommentPush publishes a comment on a PR using Bitbucket Server REST API.

BitBucketServerPRCommentPush(base_url, user, password, messageFormatter=None, verbose=False, debug=None, verify=None, mode=('failing', 'passing', 'warnings'), tags=None, builders=None, schedulers=None, branches=None, buildSetSummary=False):
  • base_url (string) – The base url of the Bitbucket server host
  • user (string) – The Bitbucket server user to post as. (can be a Secret)
  • password (string) – The Bitbucket server user’s password. (can be a Secret)
  • messageFormatter – This is an optional instance of MessageFormatter that can be used to generate a custom comment.
  • verbose (boolean) – If True, logs a message for each successful status push.
  • debug (boolean) – logs every requests and their response
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • mode (list) –

    A list of strings which will determine the build status that will be reported. The values could be changefailingpassingproblemwarnings or exception. There are two shortcuts:

    Equivalent to (changefailingpassingproblemwarningsexception)
    Equivalent to (warningsfailing).
  • tags (list) – A list of tag names to serve status information for. Defaults to None(all tags). Use either builders or tags, but not both.
  • builders (list) – Only send update for specified builders. Defaults to None (all builders). Use either builders or tags, but not both
  • schedulers (list) – A list of scheduler names to serve status information for. Defaults to None (all schedulers).
  • branches (list) – A list of branch names to serve status information for. Defaults to None (all branches).
  • buildSetSummary (boolean) – If true, post a comment when a build set is finished with all build completion messages in it, instead of doing it for each separate build.


This reporter depends on the Bitbucket server hook to get the pull request url. BitbucketStatusPush
class buildbot.reporters.bitbucket.BitbucketStatusPush
from buildbot.plugins import reporters
bs = reporters.BitbucketStatusPush('oauth_key', 'oauth_secret')

BitbucketStatusPush publishes build status using Bitbucket Build Status API. The build status is published to a specific commit SHA in Bitbucket. It tracks the last build for each builderName for each commit built.

It requires txrequests package to allow interaction with the Bitbucket REST and OAuth APIs.

It uses OAuth 2.x to authenticate with Bitbucket. To enable this, you need to go to your Bitbucket Settings -> OAuth page. Click “Add consumer”. Give the new consumer a name, eg ‘buildbot’, and put in any URL as the callback (this is needed for Oauth 2.x but is not used by this reporter, eg ‘http://localhost:8010/callback’). Give the consumer Repositories:Write access. After creating the consumer, you will then be able to see the OAuth key and secret.

class BitbucketStatusPush(oauth_keyoauth_secretbase_url=''oauth_url=''builders=None)
  • oauth_key (string) – The OAuth consumer key. (can be a Secret)
  • oauth_secret (string) – The OAuth consumer secret. (can be a Secret)
  • base_url (string) – Bitbucket’s Build Status API URL
  • oauth_url (string) – Bitbucket’s OAuth API URL
  • builders (list) – only send update for specified builders
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • debug (boolean) – logs every requests and their response GitLabStatusPush
class buildbot.reporters.gitlab.GitLabStatusPush
from buildbot.plugins import reporters

gl = reporters.GitLabStatusPush('private-token', context='continuous-integration/buildbot', baseURL='')

GitLabStatusPush publishes build status using GitLab Commit Status API. The build status is published to a specific commit SHA in GitLab.

It requires txrequests package to allow interaction with GitLab Commit Status API.

It uses private token auth, and the token owner is required to have at least developer access to each repository. As a result, we recommend you use https in your base_url rather than http.

class GitLabStatusPush(tokenstartDescription=NoneendDescription=Nonecontext=NonebaseURL=Noneverbose=False)
  • token (string) – Private token of user permitted to update status for commits. (can be a Secret)
  • startDescription (string) – Description used when build starts
  • endDescription (string) – Description used when build ends
  • context (string) – Name of your build system, eg. continuous-integration/buildbot
  • baseURL (string) – the base url of the GitLab host, up to and optionally including the first / of the path. Do not include /api/
  • verbose (string) – Be more verbose
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • debug (boolean) – logs every requests and their response HipchatStatusPush
class buildbot.reporters.hipchat.HipchatStatusPush
from buildbot.plugins import reporters

hs = reporters.HipchatStatusPush('private-token', endpoint='')

HipchatStatusPush publishes a custom message using Hipchat API v2. The message is published to a user and/or room in Hipchat,

It requires txrequests package to allow interaction with Hipchat API.

It uses API token auth, and the token owner is required to have at least message/notification access to each destination.

HipchatStatusPush(auth_token, endpoint="",
builder_room_map=None, builder_user_map=None,
wantProperties=False, wantSteps=False, wantPreviousBuild=False, wantLogs=False)
  • auth_token (string) – Private API token with access to the “Send Message” and “Send Notification” scopes. (can be a Secret)
  • endpoint (string) – (optional) URL of your Hipchat server. Defaults to
  • builder_room_map (dictionary) – (optional) If specified, will forward events about a builder (based on name) to the corresponding room ID.
  • builder_user_map (dictionary) – (optional) If specified, will forward events about a builder (based on name) to the corresponding user ID.
  • wantProperties (boolean) – (optional) include ‘properties’ in the build dictionary
  • wantSteps (boolean) – (optional) include ‘steps’ in the build dictionary
  • wantLogs (boolean) – (optional) include ‘logs’ in the steps dictionaries. This needs wantSteps=True. This dumps the full content of logs.
  • wantPreviousBuild (boolean) – (optional) include ‘prev_build’ in the build dictionary
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • debug (boolean) – logs every requests and their response


No message will be sent if the message is empty or there is no destination found.


If a builder name appears in both the room and user map, the same message will be sent to both destinations.

Json object spec

The default json object contains the minimal required parameters to send a message to Hipchat.

    "message": "Buildbot started/finished build MyBuilderName (with result success) here:",
    "id_or_email": "12"

If you require different parameters, the Hipchat reporter utilizes the template design pattern and will call getRecipientList getMessage getExtraParams before sending a message. This allows you to easily override the default implementation for those methods. All of those methods can be deferred.

Method signatures:

  • build – A Build object
  • event_name (string) – the name of the event trigger for this invocation. either ‘new’ or ‘finished’


The deferred should return a dictionary containing the key(s) ‘id_or_email’ for a private user message and/or ‘room_id_or_name’ for room notifications.

  • build – A Build object
  • event_name (string) – the name of the event trigger for this invocation. either ‘new’ or ‘finished’


The deferred should return a string to send to Hipchat.

  • build – A Build object
  • event_name (string) – the name of the event trigger for this invocation. either ‘new’ or ‘finished’


The deferred should return a dictionary containing any extra parameters you wish to include in your JSON POST request that the Hipchat API can consume.

Here’s a complete example:

class MyHipchatStatusPush(HipChatStatusPush):
    name = "MyHipchatStatusPush"

    # send all messages to the same room
    def getRecipientList(self, build, event_name):
        return {
            'room_id_or_name': 'AllBuildNotifications'

    # only send notifications on finished events
    def getMessage(self, build, event_name):
        event_messages = {
            'finished': 'Build finished.'
        return event_messages.get(event_name, '')

    # color notifications based on the build result
    # and alert room on build failure
    def getExtraParams(self, build, event_name):
        result = {}
        if event_name == 'finished':
            result['color'] = 'green' if build['results'] == 0 else 'red'
            result['notify'] = (build['results'] != 0)
        return result GerritVerifyStatusPush
class buildbot.status.status_gerrit_verify_status.GerritVerifyStatusPush

GerritVerifyStatusPush sends a verify status to Gerrit using the verify-status Gerrit plugin.

It is an alternate method to GerritStatusPush, which uses the SSH API to send reviews.

The verify-status plugin allows several CI statuses to be sent for the same change, and display them separately in the Gerrit UI.

Most parameters are renderables

baseURL, auth,
startDescription="Build started.", endDescription="Build done.",
verification_name=Interpolate("%(prop:buildername)s"), abstain=False, category=None, reporter=None,
verbose=False, **kwargs)
  • baseURL (string) – Gerrit HTTP base URL
  • auth (string) – a requests authentication configuration. (can be a Secret) if Gerrit is configured with BasicAuth, then it shall be ('login', 'password') if Gerrit is configured with DigestAuth, then it shall be requests.auth.HTTPDigestAuth('login', 'password') from the requests module.
  • string startDescription (renderable) – the comment sent when the build is starting.
  • string endDescription (renderable) – the comment sent when the build is finishing.
  • string verification_name (renderable) – the name of the job displayed in the Gerrit UI.
  • boolean abstain (renderable) – whether this results should be counted as voting.
  • boolean category (renderable) – Category of the build.
  • boolean reporter (renderable) – The user that verified this build
  • verbose (boolean) – Whether to log every requests.
  • builders (list) – only send update for specified builders
  • verify (boolean) – disable ssl verification for the case you use temporary self signed certificates
  • debug (boolean) – logs every requests and their response

This reporter is integrated with GerritChangeSource, and will update changes detected by this change source.

This reporter can also send reports for changes triggered manually provided that there is a property in the build named gerrit_changes, containing the list of changes that were tested. This property must be a list of dictionaries, containing change_id and revision_id keys, as defined in the revision endpoints of the Gerrit documentation

2.5.13. Web Server


As of Buildbot 0.9.0, the built-in web server replaces the old WebStatus plugin.

Buildbot contains a built-in web server. This server is configured with the www configuration key, which specifies a dictionary with the following keys:

The TCP port on which to serve requests. Note that SSL is not supported. To host Buildbot with SSL, use an HTTP proxy such as lighttpd, nginx, or Apache. If this is None, the default, then the master will not implement a web server.
The number of seconds into the future at which an HTTP API response should expire.
The minimum supported REST API version. Any versions less than this value will not be available. This can be used to ensure that no clients are depending on API versions that will soon be removed from Buildbot.

This key gives a dictionary of additional UI plugins to load, along with configuration for those plugins. These plugins must be separately installed in the Python environment, e.g., pip installbuildbot-waterfall-view. See UI plugins For example:

c['www'] = {
    'plugins': {'waterfall_view': True}
If true, then debugging information will be output to the browser. This is best set to false (the default) on production systems, to avoid the possibility of information leakage.
This gives a list of origins which are allowed to access the Buildbot API (including control via JSONRPC 2.0). It implements cross-origin request sharing (CORS), allowing pages at origins other than the Buildbot UI to use the API. Each origin is interpreted as filename match expression, with ? matching one character and * matching anything. Thus ['*'] will match all origins, and ['https://*'] will match secure sites under The Buildbot UI will operate correctly without this parameter; it is only useful for allowing access from other web applications.
Authentication module to use for the web server. See Authentication plugins.

List of methods that can be used to get avatar pictures to use for the web server. By default, buildbot uses Gravatar to get images associated with each users, if you want to disable this you can just specify empty list:

c['www'] = {
    'avatar_methods': []

For use of corporate pictures, you can use LdapUserInfo, which can also acts as an avatar provider. See Authentication plugins.

Filename used for http access logs, relative to the master directory. If set to None or the empty string, the content of the logs will land in the main twisted.log log file. (Default to http.log)
The amount of bytes after which the http.log file will be rotated. (Default to the same value as for the twisted.log file, set in buildbot.tac)
The amount of log files that will be kept when rotating (Default to the same value as for the twisted.log file, set in buildbot.tac)

Custom component versions that you’d like to display on the About page. Buildbot will automatically prepend the versions of Python, twisted and buildbot itself to the list.

versions should be a list of tuples. for example:

c['www'] = {
    # ...
    'versions': [
        ('master.cfg', '0.1'),
        ('OS', 'Ubuntu 14.04'),

The first element of a tuple stands for the name of the component, the second stands for the corresponding version.


This directory will be parsed for custom angularJS templates to replace the one of the original website templates. if the directory string is relative, it will be joined to the master’s basedir. Either *.jade files or *.html files can be used, and will be used to override views/<filename>.htmltemplates in the angularjs templateCache. Unlike with the regular nodejs based angularjs build system, Python only jade interpreter is used to parse the jade templates. pip install pyjade is be required to use jade templates. You can also override plugin’s directives, but they have to be in another directory.

# replace the template whose source is in:
# www/base/src/app/builders/build/build.tpl.jade

# replace the template whose source is in
# www/console_view/src/module/view/builders-header/buildersheader.tpl.jade

Known differences between nodejs jade and pyjade:

See Change Hooks.


This allows to define the timeout of the session cookie. Should be a datetime.timedelta. Default is one week.

import datetime
c['www'] = {
    # ...
    'cookie_expiration_time': datetime.timedelta(weeks=2)


Settings in the settings page are stored per browser. This configuration parameter allows to override the default settings for all your users. If a user already have changed a value from the default, this will have no effect to him/her. The settings page in the UI will tell you what to insert in your master.cfg to reproduce the configuration you have in your own browser. Example use:

c['www']['ui_default_config'] = {
    'Builders.buildFetchLimit': 500,
    'Workers.showWorkerBuilders': True,


The buildbotURL configuration value gives the base URL that all masters will use to generate links. The www configuration gives the settings for the webserver. In simple cases, the buildbotURL contains the hostname and port of the master, e.g., In more complex cases, with multiple masters, web proxies, or load balancers, the correspondence may be less obvious. UI plugins
Waterfall View

Waterfall shows the whole buildbot activity in vertical time line. Builds are represented with boxes whose height vary according to their duration. Builds are sorted by builders in the horizontal axes, which allows you to see how builders are scheduled together.

pip install buildbot-waterfall-view
c['www'] = {
    'plugins': {'waterfall_view': True}


Waterfall is the emblematic view of Buildbot Eight. It allowed to see the whole Buildbot activity very quickly. Waterfall however had big scalability issues, and larger installs had to disable the page in order to avoid tens of seconds master hang because of a big waterfall page rendering. The whole Buildbot Eight internal status API has been tailored in order to make Waterfall possible. This is not the case anymore with Buildbot Nine, which has a more generic and scalable Data API and REST API. This is the reason why Waterfall does not display the steps details anymore. However nothing is impossible. We could make a specific REST api available to generate all the data needed for waterfall on the server. Please step-in if you want to help improve Waterfall view.

Console View

Console view shows the whole buildbot activity arranged by changes as discovered by Change Sources and Changes vertically and builders horizontally. If a builder has no build in the current time range, it will not be displayed. If no change is available for a build, then it will generate a fake change according to the got_revision property.

Console view will also group the builders by tags. When there are several tags defined per builders, it will first group the builders by the tag that is defined for most builders. Then given those builders, it will group them again in another tag cluster. In order to keep the UI usable, you have to keep your tags short!

pip install buildbot-console-view
c['www'] = {
    'plugins': {'console_view': True}


Nine’s Console View is the equivalent of Buildbot Eight’s Console and tgrid views. Unlike Waterfall, we think it is now feature equivalent and even better, with its live update capabilities. Please submit an issue if you think there is an issue displaying your data, with screen shots of what happen and suggestion on what to improve.

Grid View

Grid view shows the whole buildbot activity arranged by builders vertically and changes horizontally. It is equivalent to Buildbot Eight’s grid view.

By default, changes on all branches are displayed but only one branch may be filtered by the user. Builders can also be filtered by tags. This feature is similar to the one in the builder list.

pip install buildbot-grid-view
c['www'] = {
    'plugins': {'grid_view': True}

Buildbot badges plugin produces an image in SVG or PNG format with information about the last build for the given builder name. PNG generation is based on the CAIRO SVG engine, it requires a bit more CPU to generate.

pip install buildbot-badges
c['www'] = {
    'plugins': {'badges': {}}

You can the access your builder’s badges using urls like http://<buildbotURL>/badges/<buildername>.svg. The default templates are very much configurable via the following options.

    "left_text": "Build Status",  # text on the left part of the image
    "left_color": "#555",  # color of the left part of the image
    "style": "flat",  # style of the template availables are "flat", "flat-square", "plastic"
    "template_name": "{style}.svg.j2",  # name of the template
    "font_face": "DejaVu Sans",
    "font_size": 11,
    "color_scheme": {  # color to be used for right part of the image
        "exception": "#007ec6",  # blue
        "failure": "#e05d44",    # red
        "retry": "#007ec6",      # blue
        "running": "#007ec6",    # blue
        "skipped": "a4a61d",     # yellowgreen
        "success": "#4c1",       # brightgreen
        "unknown": "#9f9f9f",    # lightgrey
        "warnings": "#dfb317"    # yellow

Those options can be configured either using the plugin configuration:

c['www'] = {
    'plugins': {'badges': {"left_color": "#222"}}

Or via the URL arguments like http://<buildbotURL>/badges/<buildername>.svg?left_color=222. Custom templates can also be specified in a template directory nearby the master.cfg. Authentication plugins

By default, Buildbot does not require people to authenticate in order to access control features in the web UI. To secure Buildbot, you will need to configure an authentication plugin.


To secure the Buildbot web interface, authorization rules must be provided via the ‘authz’ configuration. If you simply wish to lock down a Buildbot instance so that only read only access is permitted, you can restrict access to control endpoints to an unpopulated ‘admin’ role. For example:

c['www']['authz'] = util.Authz(allowRules=[util.AnyControlEndpointMatcher(role="admins")],roleMatchers=[])


As of Buildbot 0.9.4, user session is managed via a JWT token, using HS256 algorithm. The session secret is stored in the database in the object_state table with name column being session_secret. Please make sure appropriate access restriction is made to this database table.

Authentication plugins are implemented as classes, and passed as the auth parameter to www.

The available classes are described here:

class buildbot.www.auth.NoAuth

This class is the default authentication plugin, which disables authentication

class buildbot.www.auth.UserPasswordAuth(users)
Parameters: users – list of ("user","password") tuples, or a dictionary of {"user": "password",..}

Simple username/password authentication using a list of user/password tuples provided in the configuration file.

from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.UserPasswordAuth({"homer": "doh!"}),
class buildbot.www.auth.CustomAuth

This authentication class means to be overridden with a custom check_credentials method that gets username and password as arguments and check if the user can login. You may use it e.g. to check the credentials against an external database or file.


from buildbot.plugins import util

class MyAuth(util.CustomAuth):
def check_credentials(self, user, password):
if user == ‘snow’ and password == ‘white’:
return True
return False

from buildbot.plugins import util c[‘www’][‘auth’] = MyAuth()

class buildbot.www.auth.HTPasswdAuth(passwdFile)
Parameters: passwdFile – An .htpasswd file to read

This class implements simple username/password authentication against a standard .htpasswdfile.

from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.HTPasswdAuth("my_htpasswd"),
class buildbot.www.oauth2.GoogleAuth(clientIdclientSecret)
  • clientId – The client ID of your buildbot application
  • clientSecret – The client secret of your buildbot application

This class implements an authentication with Google single sign-on. You can look at the Googleoauth2 documentation on how to register your Buildbot instance to the Google systems. The developer console will give you the two parameters you have to give to GoogleAuth

Register your Buildbot instance with the BUILDBOT_URL/auth/login url as the allowed redirect URI.


from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.GoogleAuth("clientid", "clientsecret"),

in order to use this module, you need to install the Python requests module

pip install requests
class buildbot.www.oauth2.GitHubAuth(clientIdclientSecret)
param clientId: The client ID of your buildbot application
param clientSecret:
The client secret of your buildbot application
param serverURL:
The server URL if this is a GitHub Enterprise server.
param apiVersion:
The GitHub API version to use. One of 3 or 4 (V3/REST or V4/GraphQL). Default=3.
param getTeamsMembership:
When True fetch all team memberships for each or the organizations the user belongs to. The teams will be included in the user’s groups as org-name/team-name.
param debug: When True and using apiVersion=4 show some additional log calls with the GraphQL queries and responses for debugging purposes.

This class implements an authentication with GitHub single sign-on. It functions almost identically to the GoogleAuth class.

Register your Buildbot instance with the BUILDBOT_URL/auth/login url as the allowed redirect URI.

The user’s email-address (for e.g. authorization) is set to the “primary” address set by the user in GitHub. When using group-based authorization, the user’s groups are equal to the names of the GitHub organizations the user is a member of.


from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.GitHubAuth("clientid", "clientsecret"),

Example for Enterprise GitHub:

from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.GitHubAuth("clientid", "clientsecret", ""),

An example on fetching team membership could be:

from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.GitHubAuth("clientid", "clientsecret", apiVersion=4, getTeamsMembership=True),
    'authz': util.Authz(

If the buildbot organization had two teams, for example, ‘core-developers’ and ‘contributors’, with the above example, any user belonging to those teams would be granted the roles matching those team names.

class buildbot.www.oauth2.GitLabAuth(instanceUriclientIdclientSecret)
  • instanceUri – The URI of your GitLab instance
  • clientId – The client ID of your buildbot application
  • clientSecret – The client secret of your buildbot application

This class implements an authentication with GitLab single sign-on. It functions almost identically to the GoogleAuth class.

Register your Buildbot instance with the BUILDBOT_URL/auth/login url as the allowed redirect URI.


from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.GitLabAuth("", "clientid", "clientsecret"),
class buildbot.www.oauth2.BitbucketAuth(clientIdclientSecret)
  • clientId – The client ID of your buildbot application
  • clientSecret – The client secret of your buildbot application

This class implements an authentication with Bitbucket single sign-on. It functions almost identically to the GoogleAuth class.

Register your Buildbot instance with the BUILDBOT_URL/auth/login url as the allowed redirect URI.


from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.BitbucketAuth("clientid", "clientsecret"),
class buildbot.www.auth.RemoteUserAuth
  • header – header to use to get the username (defaults to REMOTE_USER)
  • headerRegex – regular expression to get the username from header value (defaults to "(?P<username>[^ @]+)@(?P<realm>[^ @]+)"). Note that your at least need to specify a ?P<username> regular expression named group.
  • userInfoProvider – user info provider; see User Information

If the Buildbot UI is served through a reverse proxy that supports HTTP-based authentication (like apache or lighttpd), it’s possible to to tell Buildbot to trust the web server and get the username from th request headers.

Administrator must make sure that it’s impossible to get access to Buildbot using other way than through frontend. Usually this means that Buildbot should listen for incoming connections only on localhost (or on some firewall-protected port). The reverse proxy must require HTTP authentication to access Buildbot pages (using any source for credentials, such as htpasswd, PAM, LDAP, Kerberos).


from buildbot.plugins import util
c['www'] = {
    # ...
    'auth': util.RemoteUserAuth(),

A corresponding Apache configuration example

<Location "/">
        AuthType Kerberos
        AuthName "Buildbot login via Kerberos"
        KrbMethodNegotiate On
        KrbMethodK5Passwd On
        KrbAuthRealms <<YOUR CORP REALMS>>
        KrbVerifyKDC off
        KrbServiceName Any
        Krb5KeyTab /etc/krb5/krb5.keytab
        KrbSaveCredentials Off
        require valid-user
        Order allow,deny

        Satisfy Any

        #] SSO
        RewriteEngine On
        RewriteCond %{LA-U:REMOTE_USER} (.+)$
        RewriteRule . - [E=RU:%1,NS]
        RequestHeader set REMOTE_USER %{RU}e


The advantage of this sort of authentication is that it is uses a proven and fast implementation for authentication. The problem is that the only information that is passed to Buildbot is the username, and there is no way to pass any other information like user email, user groups, etc. That information can be very useful to the mailstatus plugin, or for authorization processes. See User Information for a mechanism to supply that information. User Information

For authentication mechanisms which cannot provide complete information about a user, Buildbot needs another way to get user data. This is useful both for authentication (to fetch more data about the logged-in user) and for avatars (to fetch data about other users).

This extra information is provided by, appropriately enough, user info providers. These can be passed to RemoteUserAuth and as an element of avatar_methods.

This can also be passed to oauth2 authentication plugins. In this case the username provided by oauth2 will be used, and all other information will be taken from ldap (Full Name, email, and groups):

Currently only one provider is available:

class buildbot.ldapuserinfo.LdapUserInfo(uribindUserbindPwaccountBaseaccountPatterngroupBase=NonegroupMemberPattern=NonegroupName=NoneaccountFullNameaccountEmailavatarPattern=NoneavatarData=NoneaccountExtraFields=None)
  • uri – uri of the ldap server
  • bindUser – username of the ldap account that is used to get the infos for other users (usually a “faceless” account)
  • bindPw – password of the bindUser
  • accountBase – the base dn (distinguished name)of the user database
  • accountPattern – the pattern for searching in the account database. This must contain the %(username)s string, which is replaced by the searched username
  • accountFullName – the name of the field in account ldap database where the full user name is to be found.
  • accountEmail – the name of the field in account ldap database where the user email is to be found.
  • groupBase – the base dn of the groups database.
  • groupMemberPattern – the pattern for searching in the group database. This must contain the %(dn)s string, which is replaced by the searched username’s dn
  • groupName – the name of the field in groups ldap database where the group name is to be found.
  • avatarPattern – the pattern for searching avatars from emails in the account database. This must contain the %(email)s string, which is replaced by the searched email
  • avatarData – the name of the field in groups ldap database where the avatar picture is to be found. This field is supposed to contain the raw picture, format is automatically detected from jpeg, png or git.
  • accountExtraFields – extra fields to extracts for use with the authorization policies.

If one of the three optional groups parameters is supplied, then all of them become mandatory. If none is supplied, the retrieved user info has an empty list of groups.


from buildbot.plugins import util

# this configuration works for MS Active Directory ldap implementation
# we use it for user info, and avatars
userInfoProvider = util.LdapUserInfo(
c['www'] = dict(port=PORT, allowed_origins=["*"],


In order to use this module, you need to install the ldap3 module:

pip install ldap3

In the case of oauth2 authentications, you have to pass the userInfoProvider as keyword argument:

from buildbot.plugins import util
userInfoProvider = util.LdapUserInfo(...)
c['www'] = {
    # ...
    'auth': util.GoogleAuth("clientid", "clientsecret", userInfoProvider=userInfoProvider),
} Reverse Proxy Configuration

It is usually better to put buildbot behind a reverse proxy in production.

  • Provides automatic gzip compression
  • Provides SSL support with a widely used implementation
  • Provides support for http/2 or spdy for fast parallel REST api access from the browser

Reverse proxy however might be problematic for websocket, you have to configure it specifically to pass web socket requests. Here is an nginx configuration that is known to work (nginx 1.6.2):

server {
        # Enable SSL and http2
        listen 443 ssl http2 default_server;


        root html;
        index index.html index.htm;

        ssl on;
        ssl_certificate /etc/nginx/ssl/server.cer;
        ssl_certificate_key /etc/nginx/ssl/server.key;

        # put a one day session timeout for websockets to stay longer
        ssl_session_cache      shared:SSL:10m;
        ssl_session_timeout  1440m;

        # please consult latest nginx documentation for current secure encryption settings
        ssl_protocols ..
        ssl_ciphers ..
        ssl_prefer_server_ciphers   on;

        # force https
        add_header Strict-Transport-Security "max-age=31536000; includeSubdomains;";
        spdy_headers_comp 5;

        proxy_set_header HOST $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto  $scheme;
        proxy_set_header X-Forwarded-Server  $host;
        proxy_set_header X-Forwarded-Host  $host;

        # you could use / if you use domain based proxy instead of path based proxy
        location /buildbot/ {
        location /buildbot/sse/ {
            # proxy buffering will prevent sse to work
            proxy_buffering off;
        # required for websocket
        location /buildbot/ws {
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";
            # raise the proxy timeout for the websocket
            proxy_read_timeout 6000s;

To run with Apache2, you’ll need mod_proxy_wstunnel in addition to mod_proxy_http. Serving HTTPS (mod_ssl) is advised to prevent issues with enterprise proxies (see Server Sent Events), even if you don’t need the encryption itself.

Here is a configuration that is known to work (Apache 2.4.10 / Debian 8, Apache 2.4.25 / Debian 9, Apache 2.4.6 / CentOS 7), directly at the top of the domain.

If you want to add access control directives, just put them in a <Location />.

<VirtualHost *:443>
    ServerName buildbot.example
    ServerAdmin webmaster@buildbot.example

    # replace with actual port of your Buildbot master
    ProxyPass /ws ws://
    ProxyPassReverse /ws ws://
    ProxyPass /
    ProxyPassReverse /

    SetEnvIf X-Url-Scheme https HTTPS=1
    ProxyPreserveHost On

    SSLEngine on
    SSLCertificateFile /path/to/cert.pem
    SSLCertificateKeyFile /path/to/cert.key

    # check Apache2 documentation for current safe SSL settings
    # This is actually the Debian 8 default at the time of this writing:
    SSLProtocol all -SSLv3

</VirtualHost> Authorization rules

The authorization framework in Buildbot is very generic and flexible. Drawback is that it is not very obvious for newcomers. The ‘simple’ example will however allow you to easily start by implementing an admins-have-all-rights setup.

Please carefully read the following documentation to understand how to setup authorization in Buildbot.

Authorization framework is tightly coupled to the REST API. Authorization framework only works for HTTP, not for other means of interaction like IRC or try scheduler. It allows or denies access to the REST APIs according to rules.

UserAuthenticatedUserRoleMatcherRoleEndpointMatcherREST API EndpointAuth

  • Roles is a label that you give to a user.

    It is similar but different to the usual notion of group:

    • A user can have several roles, and a role can be given to several users.
    • Role is an application specific notion, while group is more organization specific notion.
    • Groups are given by the auth plugin, e.g ldapgithub, and are not always in the precise control of the buildbot admins.
    • Roles can be dynamically assigned, according to the context. For example, there is the owner role, which can be given to a user for a build that he is at the origin, so that he can stop or rebuild only builds of his own.
  • Endpoint matchers associate role requirements to REST API endpoints. The default policy is allow in case no matcher matches (see below why)

  • Role matchers associate authenticated users to roles.

Authz Configuration
class buildbot.www.authz.Authz(allowRules=[]roleMatcher=[]stringsMatcher=util.fnmatchStrMatcher)
  • allowRules – List of EndpointMatcherBase processed in order for each endpoint grant request.
  • roleMatcher – List of RoleMatchers
  • stringsMatcher – Selects algorithm used to make strings comparison (used to compare roles and builder names). can be util.fnmatchStrMatcher or util.reStrMatcher from from buildbot.plugins import util

Authz needs to be configured in c['www']['authz']

Endpoint matchers

Endpoint matchers are responsible for creating rules to match REST endpoints, and requiring roles for them. Endpoint matchers are processed in the order they are configured. The first rule matching an endpoint will prevent further rules from being checked. To continue checking other rules when the result is deny, set defaultDeny=False. If no endpoint matcher matches, then the access is granted.

One can implement the default deny policy by putting an AnyEndpointMatcher with nonexistent role in the end of the list. Please note that this will deny all REST apis, and most of the UI do not implement proper access denied message in case of such error.

The following sequence is implemented by each EndpointMatcher class.

  • Check whether the requested endpoint is supported by this matcher
  • Get necessary info from data api, and decides whether it matches.
  • Look if the users has the required role.

Several endpoints matchers are currently implemented. If you need a very complex setup, you may need to implement your own endpoint matchers. In this case, you can look at the source code for detailed examples on how to write endpoint matchers.

class buildbot.www.authz.endpointmatchers.EndpointMatcherBase(roledefaultDeny=True)
  • role – The role which grants access to this endpoint. List of roles is not supported, but a fnmatch expression can be provided to match several roles.
  • defaultDeny – The role matcher algorithm will stop if this value is true, and if the endpoint matched.

This is the base endpoint matcher. Its arguments are inherited by all the other endpoint matchers.

class buildbot.www.authz.endpointmatchers.AnyEndpointMatcher(role)
Parameters: role – The role which grants access to any endpoint.

AnyEndpointMatcher grants all rights to people with given role (usually “admins”)

class buildbot.www.authz.endpointmatchers.AnyControlEndpointMatcher(role)
Parameters: role – The role which grants access to any control endpoint.

AnyControlEndpointMatcher grants control rights to people with given role (usually “admins”) This endpoint matcher is matches current and future control endpoints. You need to add this in the end of your configuration to make sure it is future proof.

class buildbot.www.authz.endpointmatchers.ForceBuildEndpointMatcher(builderrole)
  • builder – name of the builder.
  • role – The role needed to get access to such endpoints.

ForceBuildEndpointMatcher grants right to force builds.

class buildbot.www.authz.endpointmatchers.StopBuildEndpointMatcher(builderrole)
  • builder – name of the builder.
  • role – The role needed to get access to such endpoints.

StopBuildEndpointMatcher grants rights to stop builds.

class buildbot.www.authz.endpointmatchers.RebuildBuildEndpointMatcher(builderrole)
  • builder – name of the builder.
  • role – The role needed to get access to such endpoints.

RebuildBuildEndpointMatcher grants rights to rebuild builds.

class buildbot.www.authz.endpointmatchers.EnableSchedulerEndpointMatcher(builderrole)
  • builder – name of the builder.
  • role – The role needed to get access to such endpoints.

EnableSchedulerEndpointMatcher grants rights to enable and disable schedulers via the UI.

Role matchers

Endpoint matchers are responsible for creating rules to match people and grant them roles. You can grant roles from groups information provided by the Auth plugins, or if you prefer directly to people’s email.

class buildbot.www.authz.roles.RolesFromGroups(groupPrefix)
Parameters: groupPrefix – prefix to remove from each group

RolesFromGroups grants roles from the groups of the user. If a user has group buildbot-admin, and groupPrefix is buildbot-, then user will be granted the role ‘admin’


class buildbot.www.authz.roles.RolesFromEmails(roledict)
Parameters: roledict – dictionary with key=role, and value=list of email strings

RolesFromEmails grants roles to users according to the hardcoded emails.


class buildbot.www.authz.roles.RolesFromDomain(roledict)
Parameters: roledict – dictionary with key=role, and value=list of domain strings

RolesFromDomain grants roles to users according to their email domains. If a user tried to login with email, then user will be granted the role ‘admins’.


class buildbot.www.authz.roles.RolesFromOwner(roledict)
Parameters: roledict – dictionary with key=role, and value=list of email strings

RolesFromOwner grants a given role when property owner matches the email of the user


class buildbot.www.authz.roles.RolesFromUsername(rolesusernames)
  • roles – roles to assign when the username matches.
  • usernames – list of usernames that have the roles.

RolesFromUsername grants the given roles when the username property is within the list of usernames.


    RolesFromUsername(roles=["admins"], usernames=["root"]),
    RolesFromUsername(roles=["developers", "integrators"], usernames=["Alice", "Bob"])
Example Configs

Simple config which allows admin people to control everything, but allow anonymous to look at build results:

from buildbot.plugins import *
authz = util.Authz(
auth=util.UserPasswordAuth({'': 'mypass'})
c['www']['auth'] = auth
c['www']['authz'] = authz

More complex config with separation per branch:

from buildbot.plugins import *

authz = util.Authz(
    stringsMatcher=util.fnmatchStrMatcher,  # simple matcher with '*' glob character
    # stringsMatcher = util.reStrMatcher,   # if you prefer regular expressions
        # admins can do anything,
        # defaultDeny=False: if user does not have the admin role, we continue parsing rules
        util.AnyEndpointMatcher(role="admins", defaultDeny=False),


        # *-try groups can start "try" builds
        util.ForceBuildEndpointMatcher(builder="try", role="*-try"),
        # *-mergers groups can start "merge" builds
        util.ForceBuildEndpointMatcher(builder="merge", role="*-mergers"),
        # *-releasers groups can start "release" builds
        util.ForceBuildEndpointMatcher(builder="release", role="*-releasers"),
        # if future Buildbot implement new control, we are safe with this last rule
        # role owner is granted when property owner matches the email of the user
c['www']['authz'] = authz

Using GitHub authentication and allowing access to control endpoints for users in the “Buildbot” organization:

from buildbot.plugins import *
authz = util.Authz(
auth=util.GitHubAuth('CLIENT_ID', 'CLIENT_SECRET')
c['www']['auth'] = auth
c['www']['authz'] = authz

2.5.14. Change Hooks

The /change_hook url is a magic URL which will accept HTTP requests and translate them into changes for buildbot. Implementations (such as a trivial json-based endpoint and a GitHub implementation) can be found in master/buildbot/www/hooks. The format of the url is /change_hook/DIALECT where DIALECT is a package within the hooks directory. Change_hook is disabled by default and each DIALECT has to be enabled separately, for security reasons

An example www configuration line which enables change_hook and two DIALECTS:

c['www'] = dict(
                          'base': True,
                          'somehook': {'option1':True,

Within the www config dictionary arguments, the change_hook key enables/disables the module and change_hook_dialects whitelists DIALECTs where the keys are the module names and the values are optional arguments which will be passed to the hooks.

The master/contrib/ script allows for the submission of an arbitrary change request. Run --help for more information. The base dialect must be enabled for this to work. Change Hooks Auth

By default change hook URL is not protected. Some hooks implement their own authentication method. Other requires the generic method to be secured.

To protect URL against unauthorized access you you may use change_hook_auth option.


This method uses HTTP BasicAuth, it implies the use of SSL via Reverse Proxy Configuration in order to be fully secured.

from twisted.cred import strcred
c['www'] = dict(...,

create a file changehook.passwd with content:


change_hook_auth should be a list of ICredentialsChecker. See the details of available options in Twisted documentation. Mercurial hook

The Mercurial hook uses the base dialect:

c['www'] = dict(
    change_hook_dialects={'base': True},

Once this is configured on your buildmaster add the following hook on your server-side Mercurial repository’s hgrc:

changegroup.buildbot = python:/path/to/

You’ll find master/contrib/, and its inline documentation, in the buildbot-contribrepository. GitHub hook


There is a standalone HTTP server available for receiving GitHub notifications as well: master/contrib/ This script may be useful in cases where you cannot expose the WebStatus for public consumption. Alternatively, you can setup a reverse proxy Reverse Proxy Configuration

The GitHub hook has the following parameters:

secret (default None)
Secret token to use to validate payloads.
strict (default False)
If the hook must be strict regarding valid payloads. If the value is False (default), the signature will only be checked if a secret is specified and a signature was supplied with the payload. If the value is True, a secret must be provided, and payloads without signature will be ignored.
codebase (default None)
The codebase value to include with created changes. If the value is a function (or any other callable), it will be called with the GitHub event payload as argument and the function must return the codebase value to use for the event.
class (default None)

A class to be used for processing incoming payloads. If the value is None (default), the default class – buildbot.www.hooks.github.GitHubEventHandler – will be used. The default class handles pingpush and pull_request events only. If you’d like to handle other events (see Event Types & Payloads for more information), you’d need to subclass GitHubEventHandler and add handler methods for the corresponding events. For example, if you’d like to handle blah events, your code should look something like this:

from buildbot.www.hooks.github import GitHubEventHandler

class MyBlahHandler(GitHubEventHandler):

    def handle_blah(self, payload):
        # Do some magic here
        return [], 'git'
skips (default [r'\[ *skip *ci *\]', r'\[ *ci *skip *\]'])

A list of regex pattern makes buildbot ignore the push event. For instance, if user push 3 commits and the commit message of branch head contains a key string [ci skip], buildbot will ignore this push event.

If you want to disable the skip checking, please set it to [].

github_api_endpoint (default
If you have a self-host GitHub Enterprise installation, please set this url properly.
If your GitHub or GitHub Enterprise instance does not allow anonymous communication, you need to provide an access token. Instructions can be found here <>
pullrequest_ref (default merge)
Remote ref to test if a pull request is sent to the endpoint. See the GitHub developer manual for possible values for pull requests. (e.g. head)

The simplest way to use GitHub hook is as follows:

c['www'] = dict(
    change_hook_dialects={'github': {}},

Having added this line, you should add a webhook for your GitHub project (see Creating Webhooks page at GitHub). The parameters are:

Payload URL
This URL should point to /change_hook/github relative to the root of the web status. For example, if the base URL is, then point GitHub to To specify a project associated to the repository, append ?project=name to the URL.
Content Type
Specify application/x-www-form-urlencoded or application/json.

Any value. If you provide a non-empty value (recommended), make sure that your hook is configured to use it:

c['www'] = dict(
        'github': {
            'secret': 'MY-SECRET',
Which events would you like to trigger this webhook?
Click – Let me select individual events, then select Push and Pull request – other kind of events are not currently supported.

And then press the Add Webhook button.

Github hook creates 3 kinds of changes, distinguishable by their category field:

  • None: This change is a push to a branch.

    Use util.ChangeFilter(category=None, repository="<org>/<project>")

  • 'tag': This change is a push to a tag.

    Use util.ChangeFilter(category='tag', repository="<org>/<project>")

  • 'pull': This change is from a pull-request creation or update.

    Use util.ChangeFilter(category='pull', repository="<org>/<project>") In this case, the GitHub step must be used instead of the standard Git in order to be able to pull GitHub’s magic refs. With this method, the GitHub step will always checkout the branch merged with latest master. This allows to test the result of the merge instead of just the source branch. Note that you can use the GitHub for all categories of event.


The incoming HTTP requests for this hook are not authenticated by default. Anyone who can access the web server can “fake” a request from GitHub, potentially causing the buildmaster to run arbitrary code.

To protect URL against unauthorized access you should use Change Hooks Auth option. Then change the the Payload URL of your GitHub webhook to BitBucket hook

The BitBucket hook is as simple as GitHub one and it takes no options.

c['www'] = dict(...,
    change_hook_dialects={'bitbucket': True},

When this is setup you should add a POST service pointing to /change_hook/bitbucket relative to the root of the web status. For example, it the grid URL is, then point BitBucket to To specify a project associated to the repository, append ?project=name to the URL.

Note that there is a standalone HTTP server available for receiving BitBucket notifications, as well: master/contrib/ This script may be useful in cases where you cannot expose the WebStatus for public consumption.


As in the previous case, the incoming HTTP requests for this hook are not authenticated by default. Anyone who can access the web status can “fake” a request from BitBucket, potentially causing the buildmaster to run arbitrary code.

To protect URL against unauthorized access you should use Change Hooks Auth option. Then, create a BitBucket service hook (see with a WebHook URL like

Note that as before, not using change_hook_auth can expose you to security risks. Bitbucket Cloud hook
c['www'] = dict(
    change_hook_dialects={'bitbucketcloud': {}},

When this is setup you should add a webhook pointing to /change_hook/bitbucketcloud relative to the root of the web status.

According to the type of the event, the change category is set to pushpull-createdpull-rejectedpull-updatedpull-fulfilled or ref-deleted.

The Bitbucket Cloud hook may have the following optional parameters:

codebase (default None)
The codebase value to include with changes or a callable object that will be passed the payload in order to get it.


The incoming HTTP requests for this hook are not authenticated by default. Anyone who can access the web server can “fake” a request from Bitbucket Cloud, potentially causing the buildmaster to run arbitrary code Bitbucket Server hook
c['www'] = dict(
    change_hook_dialects={'bitbucketserver': {}},

When this is setup you should add a webhook pointing to /change_hook/bitbucketserver relative to the root of the web status.

According to the type of the event, the change category is set to pushpull-createdpull-rejectedpull-updatedpull-fulfilled or ref-deleted.

The Bitbucket Server hook may have the following optional parameters:

codebase (default None)
The codebase value to include with changes or a callable object that will be passed the payload in order to get it.


The incoming HTTP requests for this hook are not authenticated by default. Anyone who can access the web server can “fake” a request from Bitbucket Server, potentially causing the buildmaster to run arbitrary code


This hook requires the bitbucket-webhooks plugin (see Poller hook

The poller hook allows you to use GET or POST requests to trigger polling. One advantage of this is your buildbot instance can poll at launch (using the pollAtLaunch flag) to get changes that happened while it was down, but then you can still use a commit hook to get fast notification of new changes.

Suppose you have a poller configured like this:

c['change_source'] = SVNPoller(

And you configure your WebStatus to enable this hook:

c['www'] = dict(...,
    change_hook_dialects={'poller': True},

Then you will be able to trigger a poll of the SVN repository by poking the /change_hook/poller URL from a commit hook like this:

curl -s -F poller= \

If no poller argument is provided then the hook will trigger polling of all polling change sources.

You can restrict which pollers the webhook has access to using the allowed option:

c['www'] = dict(...,
    change_hook_dialects={'poller': {'allowed': ['']}}
) GitLab hook
c['www'] = dict(...,
        'gitlab' : {
            'secret': '...',

The GitLab hook has the following parameters:

secret (default None)
Secret token to use to validate payloads.

When this is setup you should add a POST service pointing to /change_hook/gitlab relative to the root of the web status. For example, it the grid URL is, then point GitLab to The project and/or codebase can also be passed in the URL by appending ?project=name or ?codebase=foo to the URL. These parameters will be passed along to the scheduler.


To handle merge requests from forks properly, it’s easiest to use a GitLab source step rather than a Git source step.


Your Git or GitLab step must be configured with a git@ repourl, not a https: one, else the change from the webhook will not trigger a build.


As in the previous case, the incoming HTTP requests for this hook are not authenticated by default. Anyone who can access the web status can “fake” a request from your GitLab server, potentially causing the buildmaster to run arbitrary code.


When applicable, you need to permit access to internal/local networks. See for details.

To protect URL against unauthorized access you should either

  • set secret token in the configuration above, then set it in the GitLab service hook declaration, or
  • use the Change Hooks Auth option. Then, create a GitLab service hook (see https://your.gitlab.server/help/web_hooks) with a WebHook URL like

Note that as before, not using change_hook_auth can expose you to security risks. Gitorious Hook

The Gitorious hook is as simple as GitHub one and it also takes no options.

c['www'] = dict(...,
    change_hook_dialects={'gitorious': True},

When this is setup you should add a POST service pointing to /change_hook/gitorious relative to the root of the web status. For example, it the grid URL is, then point Gitorious to


As in the previous case, the incoming HTTP requests for this hook are not authenticated by default. Anyone who can access the web status can “fake” a request from your Gitorious server, potentially causing the buildmaster to run arbitrary code.

To protect URL against unauthorized access you should use Change Hooks Auth option. Then, create a Gitorious web hook with a WebHook URL like

Note that as before, not using change_hook_auth can expose you to security risks.


Web hooks are only available for local Gitorious installations, since this feature is not offered as part of yet. Custom Hooks

Custom hooks are supported via the Plugin Infrastructure in Buildbot mechanism. You can subclass any of the available hook handler class available in buildbot.www.hooks and register it in the plugin system, via a custom python module. For convenience, you ca also use the generic option custom_class e.g:

from buildbot.plugins import webhooks
class CustomBase(webhooks.base):
    def getChanges(self, request):
        args = request.args
        chdict = dict(
        return ([chdict], None)

c['www'] = dict(...,
        'base' : {
            'custom_class': CustomBase,

2.5.15. Custom Services

For advanced users or plugins writers, the ‘services’ key is available, and holds a list of buildbot.util.service.BuildbotService. As this feature for advanced users, it is described in the developer section of the manual.

This section will grow as soon as ready-to-use services are created.

2.5.16. DbConfig

DbConfig is an utility for master.cfg to get easy to use key/value storage in the Buildbot database

DbConfig can get and store any json-able object to the db for use by other masters or separate UI plugins to edit them.

The design is voluntary simplistic, the focus is on the easy use rather than efficiency. A separate db connection is created each time get() or set() is called.


from buildbot.plugins import util, worker

c = BuildmasterConfig = {}
c['db_url'] = 'mysql://username:password@mysqlserver/buildbot'
dbConfig = util.DbConfig(BuildmasterConfig, basedir)
workers = dbConfig.get("workers")
c['workers'] = [
    worker.Worker(worker['name'], worker['passwd'],
    for worker in workers
class DbConfig
  • BuildmasterConfig – the BuildmasterConfig, where db_url is already configured
  • basedir – basedir global variable of the master.cfg run environment. SQLite urls are relative to this dir
  • name – the name of the config variable to retrieve
  • default – in case the config variable has not been set yet, default is returned if defined, else KeyError is raised
  • name – the name of the config variable to be set
  • value – the value of the config variable to be set

2.5.17. Configurators

For advanced users or plugins writers, the configurators key is available, and holds a list of buildbot.interfaces.IConfigurator. Configurators will run after the master.cfg has been processed, and will modify the config dictionary. Configurator implementers should make sure that they are interoperable with each other, which means carefully modifying the config to avoid overriding a setting already made by the user or by another configurator. Configurators are run (thus prioritized) in the order of the configurators list. JanitorConfigurator

Buildbot stores historical information in its database. In a large installation, these can quickly consume disk space, yet in many cases developers never consult this historical information.

JanitorConfigurator creates a builder and Nightly scheduler which will regularly remove old information. At the moment it only supports cleaning of logs, but it will contain more features as we implement them.

from buildbot.plugins import util
from datetime import timedelta

# configure a janitor which will delete all logs older than one month,
# and will run on sundays at noon
c['configurators'] = [util.JanitorConfigurator(

Parameters for JanitorConfigurator are:

timedelta object describing the minimum time for which the log data should be maintained
hourdayOfWeek, …
Arguments given to the Nightly scheduler which is backing the JanitorConfigurator. Determines when the cleanup will be done. With this, you can configure it daily, weekly or even hourly if you wish. You probably want to schedule it when Buildbot is less loaded.

2.6. Customization

For advanced users, Buildbot acts as a framework supporting a customized build application. For the most part, such configurations consist of subclasses set up for use in a regular Buildbot configuration file.

This chapter describes some of the more common idioms in advanced Buildbot configurations.

At the moment, this chapter is an unordered set of suggestions:

If you’d like to clean it up, fork the project on GitHub and get started!

2.6.1. Programmatic Configuration Generation

Bearing in mind that master.cfg is a Python file, large configurations can be shortened considerably by judicious use of Python loops. For example, the following will generate a builder for each of a range of supported versions of Python:

pythons = ['python2.4', 'python2.5', 'python2.6', 'python2.7',
           'python3.2', 'python3.3']
pytest_workers = ["worker%s" % n for n in range(10)]
for python in pythons:
    f = util.BuildFactory()
    f.addStep(steps.ShellCommand(command=[python, '']))
            name="test-%s" % python,

Next step would be the loading of pythons list from a .yaml/.ini file.

2.6.2. Collapse Request Functions

The logic Buildbot uses to decide which build request can be merged can be customized by providing a Python function (a callable) instead of True or False described in Collapsing Build Requests.

Arguments for the callable are:

pointer to the master object, which can be used to make additional data api calls via
dictionary of type builder
dictionary of type buildrequest
dictionary of type buildrequest


The number of invocations of the callable is proportional to the square of the request queue length, so a long-running callable may cause undesirable delays when the queue length grows.

It should return true if the requests can be merged, and False otherwise. For example:

def collapseRequests(master, builder, req1, req2):
    "any requests with the same branch can be merged"

    # get the buildsets for each buildrequest
    selfBuildset , otherBuildset = yield defer.gatherResults(['buildsets', req1['buildsetid'])),'buildsets', req2['buildsetid']))
    selfSourcestamps = selfBuildset['sourcestamps']
    otherSourcestamps = otherBuildset['sourcestamps']

    if len(selfSourcestamps) != len(otherSourcestamps):

    for selfSourcestamp, otherSourcestamp in zip(selfSourcestamps, otherSourcestamps):
        if selfSourcestamp['branch'] != otherSourcestamp['branch']:


c['collapseRequests'] = collapseRequests

In many cases, the details of the sourcestamp and buildrequest are important.

In the following example, only buildrequest with the same “reason” are merged; thus developers forcing builds for different reasons will see distinct builds.

Note the use of the buildrequest.BuildRequest.canBeCollapsed method to access the source stamp compatibility algorithm.

def collapseRequests(master, builder, req1, req2):
    canBeCollapsed = yield buildrequest.BuildRequest.canBeCollapsed(master, req1, req2)
    if canBeCollapsed and req1.reason == req2.reason:
c['collapseRequests'] = collapseRequests

Another common example is to prevent collapsing of requests coming from a Trigger step. Triggerstep can indeed be used in order to implement parallel testing of the same source.

Buildrequests will all have the same sourcestamp, but probably different properties, and shall not be collapsed.


In most of the cases, just setting collapseRequests=False for triggered builders will do the trick.

In other cases, parent_buildid from buildset can be used:

def collapseRequests(master, builder, req1, req2):
    canBeCollapsed = yield buildrequest.BuildRequest.canBeCollapsed(master, req1, req2)
    selfBuildset , otherBuildset = yield defer.gatherResults(['buildsets', req1['buildsetid'])),'buildsets', req2['buildsetid']))
    if canBeCollapsed and selfBuildset['parent_buildid'] != None and otherBuildset['parent_buildid'] != None:
c['collapseRequests'] = collapseRequests

If it’s necessary to perform some extended operation to determine whether two requests can be merged, then the collapseRequests callable may return its result via Deferred.


Again, the number of invocations of the callable is proportional to the square of the request queue length, so a long-running callable may cause undesirable delays when the queue length grows.

For example:

def collapseRequests(master, builder, req1, req2):
    info1, info2 = yield defer.gatherResults([
    defer.returnValue(info1 == info2)

c['collapseRequests'] = collapseRequests

2.6.3. Builder Priority Functions

The prioritizeBuilders configuration key specifies a function which is called with two arguments: a BuildMaster and a list of Builder objects. It should return a list of the same Builder objects, in the desired order. It may also remove items from the list if builds should not be started on those builders. If necessary, this function can return its results via a Deferred (it is called with maybeDeferred).

A simple prioritizeBuilders implementation might look like this:

def prioritizeBuilders(buildmaster, builders):
    """Prioritize builders.  'finalRelease' builds have the highest
    priority, so they should be built before running tests, or
    creating builds."""
    builderPriorities = {
        "finalRelease": 0,
        "test": 1,
        "build": 2,
    builders.sort(key=lambda b: builderPriorities.get(, 0))
    return builders

c['prioritizeBuilders'] = prioritizeBuilders

If the change frequency is higher than the turn-around of the builders, the following approach might be helpful:

def prioritizeBuilders(buildmaster, builders):
    """Prioritize builders. First, prioritize inactive builders.
    Second, consider the last time a job was completed (no job is infinite past).
    Third, consider the time the oldest request has been queued.
    This provides a simple round-robin scheme that works with collapsed builds."""

    def isBuilding(b):
        return bool(b.building) or bool(b.old_building)

    builders.sort(key = lambda b: (isBuilding(b), b.getNewestCompleteTime(), b.getOldestRequestTime()))
    return builders

c['prioritizeBuilders'] = prioritizeBuilders

2.6.4. Build Priority Functions

When a builder has multiple pending build requests, it uses a nextBuild function to decide which build it should start first. This function is given two parameters: the Builder, and a list of BuildRequestobjects representing pending build requests.

A simple function to prioritize release builds over other builds might look like this:

def nextBuild(bldr, requests):
    for r in requests:
        if r.source.branch == 'release':
            return r
    return requests[0]

If some non-immediate result must be calculated, the nextBuild function can also return a Deferred:

def nextBuild(bldr, requests):
    d = get_request_priorities(requests)
    def pick(priorities):
        if requests:
            return sorted(zip(priorities, requests))[0][1]
    return d

The nextBuild function is passed as parameter to BuilderConfig:

... BuilderConfig(..., nextBuild=nextBuild, ...) ...

2.6.5. canStartBuild Functions

Sometimes, you cannot know in advance what workers to assign to a BuilderConfig. For example, you might need to check for the existence of a file on a worker before running a build on it. It is possible to do that by setting the canStartBuild callback.

Here is an example that checks if there is a vm property set for the build request. If it is set, it checks if a file named after it exists in the /opt/vm folder. If the file does not exist on the given worker, refuse to run the build to force the master to select another worker.

def canStartBuild(builder, wfb, request):

    vm ='vm','vm'))
    if vm:
        args = {'file': os.path.join('/opt/vm', vm)}
        cmd = RemoteCommand('stat', args, stdioLogName=None)
        cmd.worker = wfb.worker
        res = yield, wfb.worker.conn,
        if res.rc != 0:


Here is a more complete example that checks if a worker is fit to start a build. If the load average is higher than the number of CPU cores or if there is less than 2GB of free memory, refuse to run the build on that worker. Also, put that worker in quarantine to make sure no other builds are scheduled on it for a while. Otherwise, let the build start on that worker.

class FakeBuild(object):
    properties = Properties()

class FakeStep(object):
    build = FakeBuild()

def shell(command, worker, builder):
    args = {
        'command': command,
        'logEnviron': False,
        'workdir': worker.worker_basedir,
        'want_stdout': False,
        'want_stderr': False,
    cmd = RemoteCommand('shell', args, stdioLogName=None)
    cmd.worker = worker
    yield, worker.conn,

def canStartBuild(builder, wfb, request):
    # check that load is not too high
    rc = yield shell(
        'test "$(cut -d. -f1 /proc/loadavg)" -le "$(nproc)"',
        wfb.worker, builder)
    if rc != 0:
        log.msg('loadavg is too high to take new builds',

    # check there is enough free memory
    sed_expr = r's/^MemAvailable:[[:space:]]+([0-9]+)[[:space:]]+kB$/\1/p'
    rc = yield shell(
        'test "$(sed -nre \'%s\' /proc/meminfo)" -gt 2000000' % sed_expr,
        wfb.worker, builder)
    if rc != 0:
        log.msg('not enough free memory to take new builds',

    # The build may now proceed.
    # Prevent this worker from taking any other build while this one is
    # starting for 2 min. This leaves time for the build to start consuming
    # resources (disk, memory, cpu). When the quarantine is over, if the
    # same worker is subject to start another build, the above checks will
    # better reflect the actual state of the worker.
    wfb.worker.quarantine_timeout = 120

    # This does not take the worker out of quarantine, it only resets the
    # timeout value to default.


You can extend these examples using any remote command described in the Master-Worker API.

2.6.6. Customizing SVNPoller

Each source file that is tracked by a Subversion repository has a fully-qualified SVN URL in the following form: (REPOURL)(PROJECT-plus-BRANCH)(FILEPATH). When you create the SVNPoller, you give it a repourl value that includes all of the REPOURL and possibly some portion of the PROJECT-plus-BRANCHstring. The SVNPoller is responsible for producing Changes that contain a branch name and a FILEPATH(which is relative to the top of a checked-out tree). The details of how these strings are split up depend upon how your repository names its branches. PROJECT/BRANCHNAME/FILEPATH repositories

One common layout is to have all the various projects that share a repository get a single top-level directory each, with branchestags, and trunk subdirectories:


To set up a SVNPoller that watches the Amanda trunk (and nothing else), we would use the following, using the default split_file:

from buildbot.plugins import changes
c['change_source'] = changes.SVNPoller(

In this case, every Change that our SVNPoller produces will have its branch attribute set to None, to indicate that the Change is on the trunk. No other sub-projects or branches will be tracked.

If we want our ChangeSource to follow multiple branches, we have to do two things. First we have to change our repourl= argument to watch more than just amanda/trunk. We will set it to amanda so that we’ll see both the trunk and all the branches. Second, we have to tell SVNPoller how to split the (PROJECT-plus-BRANCH)(FILEPATH) strings it gets from the repository out into (BRANCH) and (FILEPATH).

We do the latter by providing a split_file function. This function is responsible for splitting something like branches/3_3/common-src/amanda.h into branch='branches/3_3' and filepath='common-src/amanda.h'. The function is always given a string that names a file relative to the subdirectory pointed to by the SVNPoller’s repourl= argument. It is expected to return a dictionary with at least the path key. The splitter may optionally set branchproject and repository. For backwards compatibility it may return a tuple of (branchname, path). It may also return None to indicate that the file is of no interest.


The function should return branches/3_3 rather than just 3_3 because the SVN checkout step, will append the branch name to the baseURL, which requires that we keep the branches component in there. Other VC schemes use a different approach towards branches and may not require this artifact.

If your repository uses this same {PROJECT}/{BRANCH}/{FILEPATH} naming scheme, the following function will work:

def split_file_branches(path):
    pieces = path.split('/')
    if len(pieces) > 1 and pieces[0] == 'trunk':
        return (None, '/'.join(pieces[1:]))
    elif len(pieces) > 2 and pieces[0] == 'branches':
        return ('/'.join(pieces[0:2]),
        return None

In fact, this is the definition of the provided split_file_branches function. So to have our Twisted-watching SVNPoller follow multiple branches, we would use this:

from buildbot.plugins import changes, util
c['change_source'] = changes.SVNPoller("svn://",

Changes for all sorts of branches (with names like "branches/1.5.x", and None to indicate the trunk) will be delivered to the Schedulers. Each Scheduler is then free to use or ignore each branch as it sees fit.

If you have multiple projects in the same repository your split function can attach a project name to the Change to help the Scheduler filter out unwanted changes:

from buildbot.plugins import util
def split_file_projects_branches(path):
    if not "/" in path:
        return None
    project, path = path.split("/", 1)
    f = util.svn.split_file_branches(path)
    if f:
        info = dict(project=project, path=f[1])
        if f[0]:
            info['branch'] = f[0]
        return info
    return f

Again, this is provided by default. To use it you would do this:

from buildbot.plugins import changes, util
c['change_source'] = changes.SVNPoller(

Note here that we are monitoring at the root of the repository, and that within that repository is a amanda subdirectory which in turn has trunk and branches. It is that amanda subdirectory whose name becomes the project field of the Change. BRANCHNAME/PROJECT/FILEPATH repositories

Another common way to organize a Subversion repository is to put the branch name at the top, and the projects underneath. This is especially frequent when there are a number of related sub-projects that all get released in a group.

For example, hosts a project named Nevow as well as one named Quotient. In a checked-out Nevow tree there is a directory named formless that contains a Python source file named This repository is accessible via webdav (and thus uses an http: scheme) through the hostname. There are many branches in this repository, and they use a ({BRANCHNAME})/({PROJECT}) naming policy.

The fully-qualified SVN URL for the trunk version of is The 1.5.x branch version of this file would have a URL of The whole Nevow trunk would be checked out with, while the Quotient trunk would be checked out using

Now suppose we want to have an SVNPoller that only cares about the Nevow trunk. This case looks just like the PROJECT/BRANCH layout described earlier:

from buildbot.plugins import changes
c['change_source'] = changes.SVNPoller("")

But what happens when we want to track multiple Nevow branches? We have to point our repourl=high enough to see all those branches, but we also don’t want to include Quotient changes (since we’re only building Nevow). To accomplish this, we must rely upon the split_file function to help us tell the difference between files that belong to Nevow and those that belong to Quotient, as well as figuring out which branch each one is on.

from buildbot.plugins import changes
c['change_source'] = changes.SVNPoller("",

The my_file_splitter function will be called with repository-relative pathnames like:

This is a Nevow file, on the trunk. We want the Change that includes this to see a filename of formless/, and a branch of None
This is a Nevow file, on a branch. We want to get branch='branches/1.5.x' and filename='formless/'.
This is a Quotient file, so we want to ignore it by having my_file_splitter return None.
This is also a Quotient file, which should be ignored.

The following definition for my_file_splitter will do the job:

def my_file_splitter(path):
    pieces = path.split('/')
    if pieces[0] == 'trunk':
        branch = None
        pieces.pop(0) # remove 'trunk'
    elif pieces[0] == 'branches':
        pieces.pop(0) # remove 'branches'
        # grab branch name
        branch = 'branches/' + pieces.pop(0)
        return None # something weird
    projectname = pieces.pop(0)
    if projectname != 'Nevow':
        return None # wrong project
    return dict(branch=branch, path='/'.join(pieces))

If you later decide you want to get changes for Quotient as well you could replace the last 3 lines with simply:

return dict(project=projectname, branch=branch, path='/'.join(pieces))

2.6.7. Writing Change Sources

For some version-control systems, making Buildbot aware of new changes can be a challenge. If the pre-supplied classes in Change Sources and Changes are not sufficient, then you will need to write your own.

There are three approaches, one of which is not even a change source. The first option is to write a change source that exposes some service to which the version control system can “push” changes. This can be more complicated, since it requires implementing a new service, but delivers changes to Buildbot immediately on commit.

The second option is often preferable to the first: implement a notification service in an external process (perhaps one that is started directly by the version control system, or by an email server) and delivers changes to Buildbot via PBChangeSource. This section does not describe this particular approach, since it requires no customization within the buildmaster process.

The third option is to write a change source which polls for changes - repeatedly connecting to an external service to check for new changes. This works well in many cases, but can produce a high load on the version control system if polling is too frequent, and can take too long to notice changes if the polling is not frequent enough. Writing a Notification-based Change Source

A custom change source must implement buildbot.interfaces.IChangeSource.

The easiest way to do this is to subclass buildbot.changes.base.ChangeSource, implementing the describe method to describe the instance. ChangeSource is a Twisted service, so you will need to implement the startService and stopService methods to control the means by which your change source receives notifications.

When the class does receive a change, it should call self.master.addChange(..) to submit it to the buildmaster. This method shares the same parameters as master.db.changes.addChange, so consult the API documentation for that function for details on the available arguments.

You will probably also want to set compare_attrs to the list of object attributes which Buildbot will use to compare one change source to another when reconfiguring. During reconfiguration, if the new change source is different from the old, then the old will be stopped and the new started. Writing a Change Poller

Polling is a very common means of seeking changes, so Buildbot supplies a utility parent class to make it easier. A poller should subclass buildbot.changes.base.PollingChangeSource, which is a subclass of ChangeSource. This subclass implements the Service methods, and calls the poll method according to the pollInterval and pollAtLaunch options. The poll method should return a Deferred to signal its completion.

Aside from the service methods, the other concerns in the previous section apply here, too.

2.6.8. Writing a New Latent Worker Implementation

Writing a new latent worker should only require subclassing buildbot.worker.AbstractLatentWorker and implementing start_instance and stop_instance at a minimum. AbstractLatentController
class buildbot.worker.AbstractLatentWorker

This class is the base class of all latent workers and implements some common functionality. A custom worker should only need to override start_instance and stop_instance methods.

See buildbot.worker.ec2.EC2LatentWorker for an example.


This method is responsible for starting instance that will try to connect with this master. A deferred should be returned. Any problems should use an errback. The callback value can be None, or can be an iterable of short strings to include in the “substantiate success” status message, such as identifying the instance that started.


This method is responsible for shutting down instance. A deferred should be returned. If fast is True then the function should call back as soon as it is safe to do so, as, for example, the master may be shutting down. The value returned by the callback is ignored.

2.6.9. Custom Build Classes

The standard BuildFactory object creates Build objects by default. These Builds will each execute a collection of BuildSteps in a fixed sequence. Each step can affect the results of the build, but in general there is little intelligence to tie the different steps together.

By setting the factory’s buildClass attribute to a different class, you can instantiate a different build class. This might be useful, for example, to create a build class that dynamically determines which steps to run. The skeleton of such a project would look like:

class DynamicBuild(Build):
    # override some methods

f = factory.BuildFactory()
f.buildClass = DynamicBuild

2.6.10. Factory Workdir Functions


While factory workdir function is still supported, it is better to just use the fact that workdir is a renderables attribute of every steps. A Renderable has access to much more contextual information, and also can return a deferred. So you could say build_factory.workdir =util.Interpolate("%(src:repository)s to achieve similar goal.

It is sometimes helpful to have a build’s workdir determined at runtime based on the parameters of the build. To accomplish this, set the workdir attribute of the build factory to a callable. That callable will be invoked with the list of SourceStamp for the build, and should return the appropriate workdir. Note that the value must be returned immediately - Deferreds are not supported.

This can be useful, for example, in scenarios with multiple repositories submitting changes to Buildbot. In this case you likely will want to have a dedicated workdir per repository, since otherwise a sourcing step with mode = “update” will fail as a workdir with a working copy of repository A can’t be “updated” for changes from a repository B. Here is an example how you can achieve workdir-per-repo:

def workdir(source_stamps):
    return hashlib.md5(source_stamps[0].repository).hexdigest()[:8]

build_factory = factory.BuildFactory()
build_factory.workdir = workdir

# ...
builders.append ({'name': 'mybuilder',
                  'workername': 'myworker',
                  'builddir': 'mybuilder',
                  'factory': build_factory})

The end result is a set of workdirs like

Repo1 => <worker-base>/mybuilder/a78890ba
Repo2 => <worker-base>/mybuilder/0823ba88

You could make the workdir function compute other paths, based on parts of the repo URL in the sourcestamp, or lookup in a lookup table based on repo URL. As long as there is a permanent 1:1 mapping between repos and workdir, this will work.

2.6.11. Writing New BuildSteps


The API of writing custom build steps has changed significantly in Buildbot-0.9.0. See New-Style Build Steps for details about what has changed since pre 0.9.0 releases. This section documents new-style steps.

While it is a good idea to keep your build process self-contained in the source code tree, sometimes it is convenient to put more intelligence into your Buildbot configuration. One way to do this is to write a custom BuildStep. Once written, this Step can be used in the master.cfg file.

The best reason for writing a custom BuildStep is to better parse the results of the command being run. For example, a BuildStep that knows about JUnit could look at the logfiles to determine which tests had been run, how many passed and how many failed, and then report more detailed information than a simple rc==0 -based good/bad decision.

Buildbot has acquired a large fleet of build steps, and sports a number of knobs and hooks to make steps easier to write. This section may seem a bit overwhelming, but most custom steps will only need to apply one or two of the techniques outlined here.

For complete documentation of the build step interfaces, see BuildSteps. Writing BuildStep Constructors

Build steps act as their own factories, so their constructors are a bit more complex than necessary. The configuration file instantiates a BuildStep object, but the step configuration must be re-used for multiple builds, so Buildbot needs some way to create more steps.

Consider the use of a BuildStep in master.cfg:

f.addStep(MyStep(someopt="stuff", anotheropt=1))

This creates a single instance of class MyStep. However, Buildbot needs a new object each time the step is executed. An instance of BuildStep remembers how it was constructed, and can create copies of itself. When writing a new step class, then, keep in mind are that you cannot do anything “interesting” in the constructor – limit yourself to checking and storing arguments.

It is customary to call the parent class’s constructor with all otherwise-unspecified keyword arguments. Keep a **kwargs argument on the end of your options, and pass that up to the parent class’s constructor.

The whole thing looks like this:

class Frobnify(LoggingBuildStep):
    def __init__(self,

        # check
        if frob_how_many is None:
            raise TypeError("Frobnify argument how_many is required")

        # override a parent option
        kwargs['parentOpt'] = 'xyz'

        # call parent
        LoggingBuildStep.__init__(self, **kwargs)

        # set Frobnify attributes
        self.frob_what = frob_what
        self.frob_how_many = how_many
        self.frob_how = frob_how

class FastFrobnify(Frobnify):
    def __init__(self,
        Frobnify.__init__(self, **kwargs)
        self.speed = speed Step Execution Process

A step’s execution occurs in its run method. When this method returns (more accurately, when the Deferred it returns fires), the step is complete. The method’s result must be an integer, giving the result of the step. Any other output from the step (logfiles, status strings, URLs, etc.) is the responsibility of the run method.

The ShellCommand class implements this run method, and in most cases steps subclassing ShellCommandsimply implement some of the subsidiary methods that its run method calls. Running Commands

To spawn a command in the worker, create a RemoteCommand instance in your step’s run method and run it with runCommand:

cmd = RemoteCommand(args)
d = self.runCommand(cmd)

The CommandMixin class offers a simple interface to several common worker-side commands.

For the much more common task of running a shell command on the worker, use ShellMixin. This class provides a method to handle the myriad constructor arguments related to shell commands, as well as a method to create new RemoteCommand instances. This mixin is the recommended method of implementing custom shell-based steps. The older pattern of subclassing ShellCommand is no longer recommended.

A simple example of a step using the shell mixin is:

class RunCleanup(buildstep.ShellMixin, buildstep.BuildStep):
    def __init__(self, cleanupScript='./', **kwargs):
        self.cleanupScript = cleanupScript
        kwargs = self.setupShellMixin(kwargs, prohibitArgs=['command'])
        buildstep.BuildStep.__init__(self, **kwargs)

    def run(self):
        cmd = yield self.makeRemoteShellCommand(
        yield self.runCommand(cmd)
        if cmd.didFail():
            cmd = yield self.makeRemoteShellCommand(
                    command=[self.cleanupScript, '--force'],
            yield self.runCommand(cmd)

def run(self):
    cmd = RemoteCommand(args)
    log = yield self.addLog('output')
    cmd.useLog(log, closeWhenFinished=True)
    yield self.runCommand(cmd) Updating Status Strings

Each step can summarize its current status in a very short string. For example, a compile step might display the file being compiled. This information can be helpful users eager to see their build finish.

Similarly, a build has a set of short strings collected from its steps summarizing the overall state of the build. Useful information here might include the number of tests run, but probably not the results of a make clean step.

As a step runs, Buildbot calls its getCurrentSummary method as necessary to get the step’s current status. “As necessary” is determined by calls to buildbot.process.buildstep.BuildStep.updateSummary. Your step should call this method every time the status summary may have changed. Buildbot will take care of rate-limiting summary updates.

When the step is complete, Buildbot calls its getResultSummary method to get a final summary of the step along with a summary for the build. About Logfiles

Each BuildStep has a collection of log files. Each one has a short name, like stdio or warnings. Each log file contains an arbitrary amount of text, usually the contents of some output file generated during a build or test step, or a record of everything that was printed to stdout/stderr during the execution of some command.

Each can contain multiple channels, generally limited to three basic ones: stdout, stderr, and headers. For example, when a shell command runs, it writes a few lines to the headers channel to indicate the exact argv strings being run, which directory the command is being executed in, and the contents of the current environment variables. Then, as the command runs, it adds a lot of stdout and stderrmessages. When the command finishes, a final header line is added with the exit code of the process.

Status display plugins can format these different channels in different ways. For example, the web page shows log files as text/html, with header lines in blue text, stdout in black, and stderr in red. A different URL is available which provides a text/plain format, in which stdout and stderr are collapsed together, and header lines are stripped completely. This latter option makes it easy to save the results to a file and run grep or whatever against the output. Writing Log Files

Most commonly, logfiles come from commands run on the worker. Internally, these are configured by supplying the RemoteCommand instance with log files via the useLog method:

def run(self):
    log = yield self.addLog('stdio')
    cmd.useLog(log, closeWhenFinished=True, 'stdio')
    yield self.runCommand(cmd)

The name passed to useLog must match that configured in the command. In this case, stdio is the default.

If the log file was already added by another part of the step, it can be retrieved with getLog:

stdioLog = self.getLog('stdio')

Less frequently, some master-side processing produces a log file. If this log file is short and easily stored in memory, this is as simple as a call to addCompleteLog:

def run(self):
    summary = u'\n'.join('%s: %s' % (k, count)
                         for (k, count) in self.lint_results.iteritems())
    yield self.addCompleteLog('summary', summary)

Note that the log contents must be a unicode string.

Longer logfiles can be constructed line-by-line using the add methods of the log file:

def run(self):
    updates = yield self.addLog('updates')
    while True:
        yield updates.addStdout(some_update)

Again, note that the log input must be a unicode string.

Finally, addHTMLLog is similar to addCompleteLog, but the resulting log will be tagged as containing HTML. The web UI will display the contents of the log using the browser.

The logfiles= argument to ShellCommand and its subclasses creates new log files and fills them in realtime by asking the worker to watch a actual file on disk. The worker will look for additions in the target file and report them back to the BuildStep. These additions will be added to the log file by calling addStdout.

All log files can be used as the source of a LogObserver just like the normal stdio LogFile. In fact, it’s possible for one LogObserver to observe a logfile created by another. Reading Logfiles

For the most part, Buildbot tries to avoid loading the contents of a log file into memory as a single string. For large log files on a busy master, this behavior can quickly consume a great deal of memory.

Instead, steps should implement a LogObserver to examine log files one chunk or line at a time.

For commands which only produce a small quantity of output, RemoteCommand will collect the command’s stdout into its stdout attribute if given the collectStdout=True constructor argument. Adding LogObservers

Most shell commands emit messages to stdout or stderr as they operate, especially if you ask them nicely with a option –verbose flag of some sort. They may also write text to a log file while they run. Your BuildStep can watch this output as it arrives, to keep track of how much progress the command has made or to process log output for later summarization.

To accomplish this, you will need to attach a LogObserver to the log. This observer is given all text as it is emitted from the command, and has the opportunity to parse that output incrementally.

There are a number of pre-built LogObserver classes that you can choose from (defined in buildbot.process.buildstep, and of course you can subclass them to add further customization. The LogLineObserver class handles the grunt work of buffering and scanning for end-of-line delimiters, allowing your parser to operate on complete stdout/stderr lines.

For example, let’s take a look at the TrialTestCaseCounter, which is used by the Trial step to count test cases as they are run. As Trial executes, it emits lines like the following:

buildbot.test.test_config.ConfigTest.testDebugPassword ... [OK]
buildbot.test.test_config.ConfigTest.testEmpty ... [OK]
buildbot.test.test_config.ConfigTest.testIRC ... [FAIL]
buildbot.test.test_config.ConfigTest.testLocks ... [OK]

When the tests are finished, trial emits a long line of ====== and then some lines which summarize the tests that failed. We want to avoid parsing these trailing lines, because their format is less well-defined than the [OK] lines.

A simple version of the parser for this output looks like this. The full version is in master/buildbot/steps/

from buildbot.plugins import util

class TrialTestCaseCounter(util.LogLineObserver):
    _line_re = re.compile(r'^([\w\.]+) \.\.\. \[([^\]]+)\]$')
    numTests = 0
    finished = False

    def outLineReceived(self, line):
        if self.finished:
        if line.startswith("=" * 40):
            self.finished = True

        m =
        if m:
            testname, result = m.groups()
            self.numTests += 1
            self.step.setProgress('tests', self.numTests)

This parser only pays attention to stdout, since that’s where trial writes the progress lines. It has a mode flag named finished to ignore everything after the ==== marker, and a scary-looking regular expression to match each line while hopefully ignoring other messages that might get displayed as the test runs.

Each time it identifies a test has been completed, it increments its counter and delivers the new progress value to the step with self.step.setProgress. This helps Buildbot to determine the ETA for the step.

To connect this parser into the Trial build step, Trial.__init__ ends with the following clause:

# this counter will feed Progress along the 'test cases' metric
counter = TrialTestCaseCounter()
self.addLogObserver('stdio', counter)
self.progressMetrics += ('tests',)

This creates a TrialTestCaseCounter and tells the step that the counter wants to watch the stdio log. The observer is automatically given a reference to the step in its step attribute. Using Properties

In custom BuildSteps, you can get and set the build properties with the getProperty and setPropertymethods. Each takes a string for the name of the property, and returns or accepts an arbitrary JSON-able (lists, dicts, strings, and numbers) object. For example:

class MakeTarball(ShellCommand):
    def start(self):
        if self.getProperty("os") == "win":
            self.setCommand([ ... ]) # windows-only command
            self.setCommand([ ... ]) # equivalent for other systems

Remember that properties set in a step may not be available until the next step begins. In particular, any Property or Interpolate instances for the current step are interpolated before the step starts, so they cannot use the value of any properties determined in that step. Using Statistics

Statistics can be generated for each step, and then summarized across all steps in a build. For example, a test step might set its warnings statistic to the number of warnings observed. The build could then sum the warnings on all steps to get a total number of warnings.

Statistics are set and retrieved with the setStatistic and getStatistic methods. The hasStatisticmethod determines whether a statistic exists.

The Build method getSummaryStatistic can be used to aggregate over all steps in a Build. BuildStep URLs

Each BuildStep has a collection of links. Each has a name and a target URL. The web display displays clickable links for each link, making them a useful way to point to extra information about a step. For example, a step that uploads a build result to an external service might include a link to the uploaded file.

To set one of these links, the BuildStep should call the addURL method with the name of the link and the target URL. Multiple URLs can be set. For example:

def run(self):
    ... # create and upload report to coverage server
    url = '' % reportname
    yield self.addURL('coverage', url)

This also works from log observers, which is helpful for instance if the build output points to an external page such as a detailed log file. The following example parses output of poudriere, a tool for building packages on the FreeBSD operating system.

Example output:

[00:00:00] Creating the reference jail... done
[00:00:01] Logs: /usr/local/poudriere/data/logs/bulk/103amd64-2018Q4/2018-10-03_05h47m30s
... build log without details (those are in the above logs directory) ...

Log observer implementation:

c = BuildmasterConfig = {}
c['titleURL'] = ''
# ...
class PoudriereLogLinkObserver(util.LogLineObserver):
    _regex = re.compile(
        r'Logs: /usr/local/poudriere/data/logs/bulk/([-_/0-9A-Za-z]+)$')

    def __init__(self):
        self._finished = False

    def outLineReceived(self, line):
        # Short-circuit if URL already found
        if self._finished:

        m =
        if m:
            self._finished = True
            # Let's assume local directory /usr/local/poudriere/data/logs/bulk
            # is available as
            poudriere_ui_url = c['titleURL'] + 'poudriere/logs/' +
            # Add URLs for build overview page and for per-package log files
            self.step.addURL('Poudriere build web interface', poudriere_ui_url)
            self.step.addURL('Poudriere logs', poudriere_ui_url + '/logs/') Discovering files

When implementing a BuildStep it may be necessary to know about files that are created during the build. There are a few worker commands that can be used to find files on the worker and test for the existence (and type) of files and directories.

The worker provides the following file-discovery related commands:

  • stat calls os.stat for a file in the worker’s build directory. This can be used to check if a known file exists and whether it is a regular file, directory or symbolic link.
  • listdir calls os.listdir for a directory on the worker. It can be used to obtain a list of files that are present in a directory on the worker.
  • glob calls glob.glob on the worker, with a given shell-style pattern containing wildcards.

For example, we could use stat to check if a given path exists and contains *.pyc files. If the path does not exist (or anything fails) we mark the step as failed; if the path exists but is not a directory, we mark the step as having “warnings”.

from buildbot.plugins import steps, util
from buildbot.interfaces import WorkerTooOldError
import stat

class MyBuildStep(steps.BuildStep):

    def __init__(self, dirname, **kwargs):
        buildstep.BuildStep.__init__(self, **kwargs)
        self.dirname = dirname

    def start(self):
        # make sure the worker knows about stat
        workerver = (self.workerVersion('stat'),
        if not all(workerver):
            raise WorkerTooOldError('need stat and glob')

        cmd = buildstep.RemoteCommand('stat', {'file': self.dirname})

        d = self.runCommand(cmd)
        d.addCallback(lambda res: self.evaluateStat(cmd))
        return d

    def evaluateStat(self, cmd):
        if cmd.didFail():
            self.step_status.setText(["File not found."])
        s = cmd.updates["stat"][-1]
        if not stat.S_ISDIR(s[stat.ST_MODE]):
            self.step_status.setText(["'tis not a directory"])

        cmd = buildstep.RemoteCommand('glob', {'path': self.dirname + '/*.pyc'})

        d = self.runCommand(cmd)
        d.addCallback(lambda res: self.evaluateGlob(cmd))
        return d

    def evaluateGlob(self, cmd):
        if cmd.didFail():
            self.step_status.setText(["Glob failed."])
        files = cmd.updates["files"][-1]
        if len(files):
            self.step_status.setText(["Found pycs"]+files)
            self.step_status.setText(["No pycs found"])

For more information on the available commands, see Master-Worker API.


Step Progress BuildStepFailed

2.6.12. Writing Dashboards with Flask or Bottle

Buildbot Nine UI is written in Javascript. This allows it to be reactive and real time, but comes at a price of a fair complexity. Sometimes, you need a dashboard displaying your build results in your own manner but learning AngularJS for that is just too much.

There is a Buildbot plugin which allows to write a server side generated dashboard, and integrate it in the UI.

# This needs buildbot and buildbot_www >= 0.9.5
pip install buildbot_wsgi_dashboards flask
  • This plugin can use any WSGI compatible web framework, Flask is a very common one, Bottle is another popular option.

  • The application needs to implement a /index.html route, which will render the html code representing the dashboard.

  • The application framework runs in a thread outside of Twisted. No need to worry about Twisted and asynchronous code. You can use python-requests or any library from the python ecosystem to access other servers.

  • You could use HTTP in order to access Buildbot REST API, but you can also use the Data API, via the provided synchronous wrapper.

    buildbot_api.dataGet(path, filters=None, fields=None, order=None, limit=None, offset=None):
    • path (tuple) – A tuple of path elements representing the API path to fetch. Numbers can be passed as strings or integers.
    • filters – result spec filters
    • fields – result spec fields
    • order – result spec order
    • limit – result spec limit
    • offset – result spec offset



    a resource or list, or None

    This is a blocking wrapper to as described in Data API. The available paths are described in the REST API, as well as the nature of return values depending on the kind of data that is fetched. Path can be either the REST path e.g. "builders/2/builds/4" or tuple e.g. ("builders", 2, "builds", 4). The latter form being more convenient if some path parts are coming from variables. The Data API and REST API are functionally equivalent except:

    • Data API does not have HTTP connection overhead.
    • Data API does not enforce authorization rules.

    buildbot_api.dataGet is accessible via the WSGI application object passed to wsgi_dashboards plugin (as per the example).

  • That html code output of the server runs inside AngularJS application.

    • It will use the CSS of the AngularJS application (including the Bootstrap CSS base). You can use custom style-sheet with a standard style tag within your html. Custom CSS will be shared with the whole Buildbot application once your dashboard is loaded. So you should make sure your custom CSS rules only apply to your dashboard (e.g. by having a specific class for your dashboard’s main div)
    • It can use some of the AngularJS directives defined by Buildbot UI (currently only buildsummary is usable).
    • It has full access to the application JS context.

Here is an example of code that you can use in your master.cfg to create a simple dashboard:

from __future__ import absolute_import
from __future__ import print_function

import os
import time

from flask import Flask
from flask import render_template

from buildbot.process.results import statusToString

mydashboardapp = Flask('test', root_path=os.path.dirname(__file__))
# this allows to work on the template without having to restart Buildbot
mydashboardapp.config['TEMPLATES_AUTO_RELOAD'] = True

def main():
    # This code fetches build data from the data api, and give it to the
    # template
    builders = mydashboardapp.buildbot_api.dataGet("/builders")

    builds = mydashboardapp.buildbot_api.dataGet("/builds", limit=20)

    # properties are actually not used in the template example, but this is
    # how you get more properties
    for build in builds:
        build['properties'] = mydashboardapp.buildbot_api.dataGet(
            ("builds", build['buildid'], "properties"))

        build['results_text'] = statusToString(build['results'])

    graph_data = [
        {'x': 1, 'y': 100},
        {'x': 2, 'y': 200},
        {'x': 3, 'y': 300},
        {'x': 4, 'y': 0},
        {'x': 5, 'y': 100},
        {'x': 6, 'y': 200},
        {'x': 7, 'y': 300},
        {'x': 8, 'y': 0},
        {'x': 9, 'y': 100},
        {'x': 10, 'y': 200},

    # mydashboard.html is a template inside the template directory
    return render_template('mydashboard.html', builders=builders, builds=builds,

# Here we assume c['www']['plugins'] has already be created earlier.
# Please see the web server documentation to understand how to configure
# the other parts.
c['www']['plugins']['wsgi_dashboards'] = [  # This is a list of dashboards, you can create several
        'name': 'mydashboard',  # as used in URLs
        'caption': 'My Dashboard',  # Title displayed in the UI'
        'app': mydashboardapp,
        # priority of the dashboard in the left menu (lower is higher in the
        # menu)
        'order': 5,
        # available icon list can be found at
        'icon': 'area-chart'

Then you need a templates/mydashboard.html file near your master.cfg.

This template is a standard Jinja template which is the default templating engine of Flask.

<div class="container mydashboard">
    /* only modify th from this dashboard! */
    .mydashboard table th {
        font-size 24pt;
    <!-- Create a table of builds organised by builders in columns -->
    <table class="table">
            <!-- Generate the table header with name of builders -->
            {% for builder in builders %}
            {% endfor %}
        {% for build in builds %}
            {% for builder in builders %}
                <!-- If this build is from this builderid, then we render it in this cell -->
                {% if build.builderid == builder.builderid %}
                <!-- for representing a build, you can choose one of those three forms -->
                    <!-- 1) We use buildbot internal CSS styles display our builds, with links to the standard UI  -->
                        <a class="badge-status badge results_{{build.results_text | upper}}" href="#/builders/{{build.builderid}}/builds/{{build.number}}">
                    <!-- 2) The buildsummary directive is very powerful and will display steps, sub-builds, logs, urls. -->
                       <buildsummary buildid="{{build.buildid}}" condensed="1"/>
                    <!-- 3) If you need something lighter, there is the build sticker directive -->
                       <buildsticker buildid="{{build.buildid}}"/>
                    <!-- Note that those two directives will make additional HTTP requests from the browser in order to fetch the necessary data they need to be rendered. -->

               {% endif %}
            {% endfor %}
        {% endfor %}
    <!-- Example of line chart using Chart.js -->
    <canvas id="myChart" width="400" height="400"></canvas>
        // We use Chart.js for rendering a chart, we first have to download it from internet
        // (will be cached by the browser)
        // See for more details
        function createChart() {
            var scatterChart = new Chart("myChart", {
            type: 'line',
            data: {
                datasets: [{
                    label: 'Github statistics',
                    // Here the data from the python is passed to the javascript via tojson and safe jinja filters
                    data: {{graph_data | tojson |safe }}
            options: {
                scales: {
                    xAxes: [{
                        type: 'linear',
                        position: 'bottom'


2.6.13. A Somewhat Whimsical Example (or “It’s now customized, how do I deploy it?”)

Let’s say that we’ve got some snazzy new unit-test framework called Framboozle. It’s the hottest thing since sliced bread. It slices, it dices, it runs unit tests like there’s no tomorrow. Plus if your unit tests fail, you can use its name for a Web 2.1 startup company, make millions of dollars, and hire engineers to fix the bugs for you, while you spend your afternoons lazily hang-gliding along a scenic pacific beach, blissfully unconcerned about the state of your tests. [1]

To run a Framboozle-enabled test suite, you just run the ‘framboozler’ command from the top of your source code tree. The ‘framboozler’ command emits a bunch of stuff to stdout, but the most interesting bit is that it emits the line “FNURRRGH!” every time it finishes running a test case You’d like to have a test-case counting LogObserver that watches for these lines and counts them, because counting them will help the buildbot more accurately calculate how long the build will take, and this will let you know exactly how long you can sneak out of the office for your hang-gliding lessons without anyone noticing that you’re gone.

This will involve writing a new BuildStep (probably named “Framboozle”) which inherits from ShellCommand. The BuildStep class definition itself will look something like this:

from buildbot.plugins import steps, util

class FNURRRGHCounter(util.LogLineObserver):
    numTests = 0
    def outLineReceived(self, line):
        if "FNURRRGH!" in line:
            self.numTests += 1
            self.step.setProgress('tests', self.numTests)

class Framboozle(steps.ShellCommand):
    command = ["framboozler"]

    def __init__(self, **kwargs):
        steps.ShellCommand.__init__(self, **kwargs)   # always upcall!
        counter = FNURRRGHCounter()
        self.addLogObserver('stdio', counter)
        self.progressMetrics += ('tests',)

So that’s the code that we want to wind up using. How do we actually deploy it?

You have a number of different options: Inclusion in the master.cfg file

The simplest technique is to simply put the step class definitions in your master.cfg file, somewhere before the BuildFactory definition where you actually use it in a clause like:

f = BuildFactory()

Remember that master.cfg is secretly just a Python program with one job: populating the BuildmasterConfig dictionary. And Python programs are allowed to define as many classes as they like. So you can define classes and use them in the same file, just as long as the class is defined before some other code tries to use it.

This is easy, and it keeps the point of definition very close to the point of use, and whoever replaces you after that unfortunate hang-gliding accident will appreciate being able to easily figure out what the heck this stupid “Framboozle” step is doing anyways. The downside is that every time you reload the config file, the Framboozle class will get redefined, which means that the buildmaster will think that you’ve reconfigured all the Builders that use it, even though nothing changed. Bleh. Python file somewhere on the system

Instead, we can put this code in a separate file, and import it into the master.cfg file just like we would the normal buildsteps like ShellCommand and SVN.

Create a directory named ~/lib/python, put the step class definitions in ~/lib/python/, and run your buildmaster using:

PYTHONPATH=~/lib/python buildbot start MASTERDIR

or use the Makefile.buildbot to control the way buildbot start works. Or add something like this to something like your ~/.bashrc or ~/.bash_profile or ~/.cshrc:

export PYTHONPATH=~/lib/python

Once we’ve done this, our master.cfg can look like:

from framboozle import Framboozle
f = BuildFactory()


import framboozle
f = BuildFactory()

(check out the Python docs for details about how import and from A import B work).

What we’ve done here is to tell Python that every time it handles an “import” statement for some named module, it should look in our ~/lib/python/ for that module before it looks anywhere else. After our directories, it will try in a bunch of standard directories too (including the one where buildbot is installed). By setting the PYTHONPATH environment variable, you can add directories to the front of this search list.

Python knows that once it “import”s a file, it doesn’t need to re-import it again. This means that reconfiguring the buildmaster (with buildbot reconfig, for example) won’t make it think the Framboozle class has changed every time, so the Builders that use it will not be spuriously restarted. On the other hand, you either have to start your buildmaster in a slightly weird way, or you have to modify your environment to set the PYTHONPATH variable. Install this code into a standard Python library directory

Find out what your Python’s standard include path is by asking it:

80:warner@luther% python
Python 2.4.4c0 (#2, Oct  2 2006, 00:57:46)
[GCC 4.1.2 20060928 (prerelease) (Debian 4.1.1-15)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> import pprint
>>> pprint.pprint(sys.path)

In this case, putting the code into /usr/local/lib/python2.4/site-packages/ would work just fine. We can use the same master.cfg import framboozle statement as in Option 2. By putting it in a standard include directory (instead of the decidedly non-standard ~/lib/python), we don’t even have to set PYTHONPATH to anything special. The downside is that you probably have to be root to write to one of those standard include directories. Distribute a Buildbot Plug-In

First of all, you must prepare a Python package (if you do not know what that is, please check How to package Buildbot plugins, where you can find a couple of pointers to tutorials).

When you have a package, you will have a special file called This file needs to be updated to include a pointer to your new step:

    entry_points = {
        'buildbot.steps': [
            'Framboozle = framboozle:Framboozle'


  • buildbot.steps is the kind of plugin you offer (more information about possible kinds you can find in How to package Buildbot plugins)

  • framboozle:Framboozle consists of two parts: framboozle is the name of the Python module where to look for Framboozle class, which implements the plugin

  • Framboozle is the name of the plugin.

    This will allow users of your plugin to use it just like any other Buildbot plugins:

    from buildbot.plugins import steps
    ... steps.Framboozle ...

Now you can upload it to PyPI where other people can download it from and use in their build systems. Once again, the information about how to prepare and upload a package to PyPI can be found in tutorials listed in How to package Buildbot plugins. Submit the code for inclusion in the Buildbot distribution

Make a fork of buildbot on or post a patch in a bug at In either case, post a note about your patch to the mailing list, so others can provide feedback and, eventually, commit it.

When it’s committed to the master, the usage is the same as in the previous approach:

from buildbot.plugins import steps, util

f = util.BuildFactory()

And then you don’t even have to install anywhere on your system, since it will ship with Buildbot. You don’t have to be root, you don’t have to set PYTHONPATH. But you do have to make a good case for Framboozle being worth going into the main distribution, you’ll probably have to provide docs and some unit test cases, you’ll need to figure out what kind of beer the author likes (IPA’s and Stouts for Dustin), and then you’ll have to wait until the next release. But in some environments, all this is easier than getting root on your buildmaster box, so the tradeoffs may actually be worth it. Summary

Putting the code in master.cfg (1) makes it available to that buildmaster instance. Putting it in a file in a personal library directory (2) makes it available for any buildmasters you might be running. Putting it in a file in a system-wide shared library directory (3) makes it available for any buildmasters that anyone on that system might be running. Getting it into the buildbot’s upstream repository (4) makes it available for any buildmasters that anyone in the world might be running. It’s all a matter of how widely you want to deploy that new class.

[1] is still available. Remember, I get 10% :).

2.7. Command-line Tool

This section describes command-line tools available after buildbot installation. Since version 0.8 the one-for-all buildbot command-line tool was divided into two parts namely buildbot and buildslave, starting from version 0.9 buildslave command was replaced with buildbot-workercommand. The last one was separated from main command-line tool to minimize dependencies required for running a worker while leaving all other functions to buildbot tool.

Every command-line tool has a list of global options and a set of commands which have their own options. One can run these tools in the following way:

buildbot [global options] command [command options]
buildbot-worker [global options] command [command options]

The buildbot command is used on the master, while buildbot-worker is used on the worker. Global options are the same for both tools which perform the following actions:

--help Print general help about available commands and global options and exit. All subsequent arguments are ignored.
--verbose Set verbose output.
--version Print current buildbot version and exit. All subsequent arguments are ignored.

You can get help on any command by specifying --help as a command option:

buildbot command --help

You can also use manual pages for buildbot and buildbot-worker for quick reference on command-line options.

The remainder of this section describes each buildbot command. See Command Line Index for a full list.

2.7.1. buildbot

The buildbot command-line tool can be used to start or stop a buildmaster or buildbot, and to interact with a running buildmaster. Some of its subcommands are intended for buildmaster admins, while some are for developers who are editing the code that the buildbot is monitoring. Administrator Tools

The following buildbot sub-commands are intended for buildmaster administrators:

buildbot create-master -r {BASEDIR}

This creates a new directory and populates it with files that allow it to be used as a buildmaster’s base directory.

You will usually want to use the option -r option to create a relocatable buildbot.tac. This allows you to move the master directory without editing this file.

buildbot upgrade-master {BASEDIR}

This upgrades a previously created buildmaster’s base directory for a new version of buildbot master source code. This will copy the web server static files, and potentially upgrade the db.

buildbot start [--nodaemon] {BASEDIR}

This starts a buildmaster which was already created in the given base directory. The daemon is launched in the background, with events logged to a file named twistd.log.

The option –nodaemon option instructs Buildbot to skip daemonizing. The process will start in the foreground. It will only return to the command-line when it is stopped.

buildbot restart [--nodaemon] {BASEDIR}

Restart the buildmaster. This is equivalent to stop followed by start The option –nodaemon option has the same meaning as for start.

buildbot stop {BASEDIR}

This terminates the daemon (either buildmaster or worker) running in the given directory. The --cleanoption shuts down the buildmaster cleanly. With --no-wait option buildbot stop command will send buildmaster shutdown signal and will immediately exit, not waiting for complete buildmaster shutdown.

buildbot sighup {BASEDIR}

This sends a SIGHUP to the buildmaster running in the given directory, which causes it to re-read its master.cfg file.

buildbot checkconfig {BASEDIR|CONFIG_FILE}

This checks if the buildmaster configuration is well-formed and contains no deprecated or invalid elements. If no arguments are used or the base directory is passed as the argument the config file specified in buildbot.tac is checked. If the argument is the path to a config file then it will be checked without using the buildbot.tac file.

buildbot cleanupdb {BASEDIR|CONFIG_FILE} [-q]

This command is frontend for various database maintenance jobs:

  • optimiselogs: This optimization groups logs into bigger chunks to apply higher level of compression. Developer Tools

These tools are provided for use by the developers who are working on the code that the buildbot is monitoring.


This lets a developer to ask the question What would happen if I committed this patch right now?. It runs the unit test suite (across multiple build platforms) on the developer’s current code, allowing them to make sure they will not break the tree when they finally commit their changes.

The buildbot try command is meant to be run from within a developer’s local tree, and starts by figuring out the base revision of that tree (what revision was current the last time the tree was updated), and a patch that can be applied to that revision of the tree to make it match the developer’s copy. This (revision, patch) pair is then sent to the buildmaster, which runs a build with that SourceStamp. If you want, the tool will emit status messages as the builds run, and will not terminate until the first failure has been detected (or the last success).

There is an alternate form which accepts a pre-made patch file (typically the output of a command like svn diff). This --diff form does not require a local tree to run from. See try –diff concerning the --diff command option.

For this command to work, several pieces must be in place: the Try_Jobdir or :Try_Userpass, as well as some client-side configuration.

Locating the master

The try command needs to be told how to connect to the try scheduler, and must know which of the authentication approaches described above is in use by the buildmaster. You specify the approach by using --connect=ssh or --connect=pb (or try_connect = 'ssh' or try_connect = 'pb' in .buildbot/options).

For the PB approach, the command must be given a option –master argument (in the form HOST:PORT) that points to TCP port that you picked in the Try_Userpass scheduler. It also takes a option –usernameand option –passwd pair of arguments that match one of the entries in the buildmaster’s userpass list. These arguments can also be provided as try_mastertry_username, and try_password entries in the .buildbot/options file.

For the SSH approach, the command must be given option –host and option –username, to get to the buildmaster host. It must also be given option –jobdir, which points to the inlet directory configured above. The jobdir can be relative to the user’s home directory, but most of the time you will use an explicit path like ~buildbot/project/trydir. These arguments can be provided in .buildbot/options as try_hosttry_usernametry_password, and try_jobdir.

If you need to use something different from the default ssh command for connecting to the remote system, you can use –ssh command line option or try_ssh in the configuration file.

The SSH approach also provides a option –buildbotbin argument to allow specification of the buildbot binary to run on the buildmaster. This is useful in the case where buildbot is installed in a virtualenvon the buildmaster host, or in other circumstances where the buildbot command is not on the path of the user given by option –username. The option –buildbotbin argument can be provided in .buildbot/options as try_buildbotbin

The following command line arguments are deprecated, but retained for backward compatibility:

--tryhost is replaced by option –host
--trydir is replaced by option –jobdir
--master is replaced by option –masterstatus

Likewise, the following .buildbot/options file entries are deprecated, but retained for backward compatibility:

  • try_dir is replaced by try_jobdir
  • masterstatus is replaced by try_masterstatus

Waiting for results

If you provide the option –wait option (or try_wait = True in .buildbot/options), the buildbot trycommand will wait until your changes have either been proven good or bad before exiting. Unless you use the option –quiet option (or try_quiet=True), it will emit a progress message every 60 seconds until the builds have completed.

The SSH connection method does not support waiting for results.

Choosing the Builders

A trial build is performed on multiple Builders at the same time, and the developer gets to choose which Builders are used (limited to a set selected by the buildmaster admin with the TryScheduler’s builderNames= argument). The set you choose will depend upon what your goals are: if you are concerned about cross-platform compatibility, you should use multiple Builders, one from each platform of interest. You might use just one builder if that platform has libraries or other facilities that allow better test coverage than what you can accomplish on your own machine, or faster test runs.

The set of Builders to use can be specified with multiple option –builder arguments on the command line. It can also be specified with a single try_builders option in .buildbot/options that uses a list of strings to specify all the Builder names:

try_builders = ["full-OSX", "full-win32", "full-linux"]

If you are using the PB approach, you can get the names of the builders that are configured for the try scheduler using the get-builder-names argument:

buildbot try --get-builder-names --connect=pb --master=... --username=... --passwd=...

Specifying the VC system

The try command also needs to know how to take the developer’s current tree and extract the (revision, patch) source-stamp pair. Each VC system uses a different process, so you start by telling the try command which VC system you are using, with an argument like option –vc=cvs or option –vc=git. This can also be provided as try_vc in .buildbot/options.

The following names are recognized: bzr cvs darcs hg git mtn p4 svn

Finding the top of the tree

Some VC systems (notably CVS and SVN) track each directory more-or-less independently, which means the try command needs to move up to the top of the project tree before it will be able to construct a proper full-tree patch. To accomplish this, the try command will crawl up through the parent directories until it finds a marker file. The default name for this marker file is .buildbot-top, so when you are using CVS or SVN you should touch .buildbot-top from the top of your tree before running buildbot try. Alternatively, you can use a filename like ChangeLog or README, since many projects put one of these files in their top-most directory (and nowhere else). To set this filename, use --topfile=ChangeLog, or set it in the options file with try_topfile = 'ChangeLog'.

You can also manually set the top of the tree with --topdir=~/trees/mytree, or try_topdir ='~/trees/mytree'. If you use try_topdir, in a .buildbot/options file, you will need a separate options file for each tree you use, so it may be more convenient to use the try_topfile approach instead.

Other VC systems which work on full projects instead of individual directories (Darcs, Mercurial, Git, Monotone) do not require try to know the top directory, so the option –try-topfile and option –try-topdir arguments will be ignored.

If the try command cannot find the top directory, it will abort with an error message.

The following command line arguments are deprecated, but retained for backward compatibility:

  • --try-topdir is replaced by option –topdir
  • --try-topfile is replaced by option –topfile

Determining the branch name

Some VC systems record the branch information in a way that try can locate it. For the others, if you are using something other than the default branch, you will have to tell the buildbot which branch your tree is using. You can do this with either the option –branch argument, or a try_branch entry in the .buildbot/options file.

Determining the revision and patch

Each VC system has a separate approach for determining the tree’s base revision and computing a patch.

try pretends that the tree is up to date. It converts the current time into a option -D time specification, uses it as the base revision, and computes the diff between the upstream tree as of that point in time versus the current contents. This works, more or less, but requires that the local clock be in reasonably good sync with the repository.
try does a svn status -u to find the latest repository revision number (emitted on the last line in the Status against revision: NN message). It then performs an svn diff -rNN to find out how your tree differs from the repository version, and sends the resulting patch to the buildmaster. If your tree is not up to date, this will result in the try tree being created with the latest revision, then backwards patches applied to bring it back to the version you actually checked out (plus your actual code changes), but this will still result in the correct tree being used for the build.
try does a bzr revision-info to find the base revision, then a bzr diff -r$base.. to obtain the patch.
hg parents --template '{node}\n' emits the full revision id (as opposed to the common 12-char truncated) which is a SHA1 hash of the current revision’s contents. This is used as the base revision. hg diff then provides the patch relative to that revision. For try to work, your working directory must only have patches that are available from the same remotely-available repository that the build process’ source.Mercurial will use.
try does a p4 changes -m1 ... to determine the latest changelist and implicitly assumes that the local tree is synced to this revision. This is followed by a p4 diff -du to obtain the patch. A p4 patch differs slightly from a normal diff. It contains full depot paths and must be converted to paths relative to the branch top. To convert the following restriction is imposed. The p4base (see P4Source) is assumed to be //depot
try does a darcs changes --context to find the list of all patches back to and including the last tag that was made. This text file (plus the location of a repository that contains all these patches) is sufficient to re-create the tree. Therefore the contents of this context file are the revision stamp for a Darcs-controlled source tree. It then does a darcs diff -u to compute the patch relative to that revision.
git branch -v lists all the branches available in the local repository along with the revision ID it points to and a short summary of the last commit. The line containing the currently checked out branch begins with “* ” (star and space) while all the others start with “  ” (two spaces). try scans for this line and extracts the branch name and revision from it. Then it generates a diff against the base revision.


I’m not sure if this actually works the way it’s intended since the extracted base revision might not actually exist in the upstream repository. Perhaps we need to add a –remote option to specify the remote tracking branch to generate a diff against.

mtn automate get_base_revision_id emits the full revision id which is a SHA1 hash of the current revision’s contents. This is used as the base revision. mtn diff then provides the patch relative to that revision. For try to work, your working directory must only have patches that are available from the same remotely-available repository that the build process’ source.Monotone will use.

patch information

You can provide the option –who=dev to designate who is running the try build. This will add the devto the Reason field on the try build’s status web page. You can also set try_who = dev in the .buildbot/options file. Note that option –who=dev will not work on version 0.8.3 or earlier masters.

Similarly, option –comment=COMMENT will specify the comment for the patch, which is also displayed in the patch information. The corresponding config-file option is try_comment.

Sending properties

You can set properties to send with your change using either the option –property=key=value option, which sets a single property, or the option –properties=key1=value1,key2=value2… option, which sets multiple comma-separated properties. Either of these can be specified multiple times. Note that the option –properties option uses commas to split on properties, so if your property value itself contains a comma, you’ll need to use the option –property option to set it.

try –diff

Sometimes you might have a patch from someone else that you want to submit to the buildbot. For example, a user may have created a patch to fix some specific bug and sent it to you by email. You’ve inspected the patch and suspect that it might do the job (and have at least confirmed that it doesn’t do anything evil). Now you want to test it out.

One approach would be to check out a new local tree, apply the patch, run your local tests, then use buildbot try to run the tests on other platforms. An alternate approach is to use the buildbot try --diff form to have the buildbot test the patch without using a local tree.

This form takes a option –diff argument which points to a file that contains the patch you want to apply. By default this patch will be applied to the TRUNK revision, but if you give the optional option –baserev argument, a tree of the given revision will be used as a starting point instead of TRUNK.

You can also use buildbot try --diff=- to read the patch from stdin.

Each patch has a patchlevel associated with it. This indicates the number of slashes (and preceding pathnames) that should be stripped before applying the diff. This exactly corresponds to the option -por option –strip argument to the patch utility. By default buildbot try --diff uses a patchlevel of 0, but you can override this with the option -p argument.

When you use option –diff, you do not need to use any of the other options that relate to a local tree, specifically option –vc, option –try-topfile, or option –try-topdir. These options will be ignored. Of course you must still specify how to get to the buildmaster (with option –connect, option –tryhost, etc). Other Tools

These tools are generally used by buildmaster administrators.


This command is used to tell the buildmaster about source changes. It is intended to be used from within a commit script, installed on the VC server. It requires that you have a PBChangeSource(PBChangeSource) running in the buildmaster (by being set in c['change_source']).

buildbot sendchange --master {MASTERHOST}:{PORT} --auth {USER}:{PASS}
        --who {USER} {FILENAMES..}

The option –auth option specifies the credentials to use to connect to the master, in the form user:pass. If the password is omitted, then sendchange will prompt for it. If both are omitted, the old default (username “change” and password “changepw”) will be used. Note that this password is well-known, and should not be used on an internet-accessible port.

The option –master and option –username arguments can also be given in the options file (see .buildbot config directory). There are other (optional) arguments which can influence the Change that gets submitted:

--branch (or option branch) This provides the (string) branch specifier. If omitted, it defaults to None, indicating the default branch. All files included in this Change must be on the same branch.
--category (or option category) This provides the (string) category specifier. If omitted, it defaults to None, indicating no category. The category property can be used by schedulers to filter what changes they listen to.
--project (or option project) This provides the (string) project to which this change applies, and defaults to ‘’. The project can be used by schedulers to decide which builders should respond to a particular change.
--repository (or option repository) This provides the repository from which this change came, and defaults to ''.
--revision This provides a revision specifier, appropriate to the VC system in use.
This provides a filename which will be opened and the contents used as the revision specifier. This is specifically for Darcs, which uses the output of darcs changes --contextas a revision specifier. This context file can be a couple of kilobytes long, spanning a couple lines per patch, and would be a hassle to pass as a command-line argument.
--property This parameter is used to set a property on the Change generated by sendchange. Properties are specified as a name:value pair, separated by a colon. You may specify many properties by passing this parameter multiple times.
--comments This provides the change comments as a single argument. You may want to use option –logfile instead.
--logfile This instructs the tool to read the change comments from the given file. If you use - as the filename, the tool will read the change comments from stdin.
--encoding Specifies the character encoding for all other parameters, defaulting to 'utf8'.
--vc Specifies which VC system the Change is coming from, one of: cvssvndarcshgbzrgitmtn, or p4. Defaults to None.

Note that in order to use this command, you need to configure a CommandlineUserManager instance in your master.cfg file, which is explained in Users Options.

This command allows you to manage users in buildbot’s database. No extra requirements are needed to use this command, aside from the Buildmaster running. For details on how Buildbot manages users, see Users.

--master The user command can be run virtually anywhere provided a location of the running buildmaster. The option –master argument is of the form MASTERHOST:PORT.
--username PB connection authentication that should match the arguments to CommandlineUserManager.
--passwd PB connection authentication that should match the arguments to CommandlineUserManager.
--op There are four supported values for the option –op argument: addupdateremove, and get. Each are described in full in the following sections.
--bb_username Used with the option –op=update option, this sets the user’s username for web authentication in the database. It requires option –bb_password to be set along with it.
--bb_password Also used with the option –op=update option, this sets the password portion of a user’s web authentication credentials into the database. The password is first encrypted prior to storage for security reasons.

When working with users, you need to be able to refer to them by unique identifiers to find particular users in the database. The option –ids option lets you specify a comma separated list of these identifiers for use with the user command.

The option –ids option is used only when using option –op=remove or option –op=get.


Users are known in buildbot as a collection of attributes tied together by some unique identifier (see Users). These attributes are specified in the form {TYPE}={VALUE} when using the option –info option. These {TYPE}={VALUE} pairs are specified in a comma separated list, so for example:

--info=svn=jdoe,git='John Doe <>'

The option –info option can be specified multiple times in the user command, as each specified option will be interpreted as a new user. Note that option –info is only used with option –op=add or with option –op=update, and whenever you use option –op=update you need to specify the identifier of the user you want to update. This is done by prepending the option –info arguments with {ID:}. If we were to update 'jschmo' from the previous example, it would look like this:

--info=jdoe:git='Joe Doe <>'

Note that option –master, option –username, option –passwd, and option –op are always required to issue the user command.

The option –master, option –username, and option –passwd options can be specified in the option file with keywords user_masteruser_username, and user_passwd, respectively. If user_master is not specified, then option –master from the options file will be used instead.

Below are examples of how each command should look. Whenever a user command is successful, results will be shown to whoever issued the command.

For option –op=add:

buildbot user --master={MASTERHOST} --op=add \
        --username={USER} --passwd={USERPW} \

For option –op=update:

buildbot user --master={MASTERHOST} --op=update \
        --username={USER} --passwd={USERPW} \

For option –op=remove:

buildbot user --master={MASTERHOST} --op=remove \
        --username={USER} --passwd={USERPW} \

For option –op=get:

buildbot user --master={MASTERHOST} --op=get \
        --username={USER} --passwd={USERPW} \

A note on option –op=update: when updating the option –bb_username and option –bb_password, the option –info doesn’t need to have additional {TYPE}={VALUE} pairs to update and can just take the {ID}portion. .buildbot config directory

Many of the buildbot tools must be told how to contact the buildmaster that they interact with. This specification can be provided as a command-line argument, but most of the time it will be easier to set them in an options file. The buildbot command will look for a special directory named .buildbot, starting from the current directory (where the command was run) and crawling upwards, eventually looking in the user’s home directory. It will look for a file named options in this directory, and will evaluate it as a Python script, looking for certain names to be set. You can just put simple name ='value' pairs in this file to set the options.

For a description of the names used in this file, please see the documentation for the individual buildbot sub-commands. The following is a brief sample of what this file’s contents could be.

# for status-reading tools
masterstatus = ''
# for 'sendchange' or the debug port
master = ''

Note carefully that the names in the options file usually do not match the command-line option name.

Equivalent to option –master for sendchange. It is the location of the pb.PBChangeSource for `sendchange.
Equivalent to option –username for the sendchange command.
Equivalent to option –branch for the sendchange command.
Equivalent to option –category for the sendchange command.
Equivalent to option –connect, this specifies how the try command should deliver its request to the buildmaster. The currently accepted values are ssh and pb.
Equivalent to option –builders, specifies which builders should be used for the try build.
Equivalent to option –vc for try, this specifies the version control system being used.
Equivalent to option –branch, this indicates that the current tree is on a non-trunk branch.


Use try_topdir, equivalent to option –try-topdir, to explicitly indicate the top of your working tree, or try_topfile, equivalent to option –try-topfile to name a file that will only be found in that top-most directory.



When try_connect is ssh, the command will use try_host for option –tryhosttry_username for option –username, and try_dir for option –trydir. Apologies for the confusing presence and absence of ‘try’.



Similarly, when try_connect is pb, the command will pay attention to try_username for option –usernametry_password for option –passwd, and try_master for option –master.


try_wait and masterstatus (equivalent to option –wait and master, respectively) are used to ask the try command to wait for the requested build to complete.

2.7.2. worker

buildbot-worker command-line tool is used for worker management only and does not provide any additional functionality. One can create, start, stop and restart the worker. create-worker

This creates a new directory and populates it with files that let it be used as a worker’s base directory. You must provide several arguments, which are used to create the initial buildbot.tac file.

The option -r option is advisable here, just like for create-master.

buildbot-worker create-worker -r {BASEDIR} {MASTERHOST}:{PORT} {WORKERNAME} {PASSWORD}

The create-worker options are described in Worker Options. start

This starts a worker which was already created in the given base directory. The daemon is launched in the background, with events logged to a file named twistd.log.

buildbot-worker start [--nodaemon] BASEDIR

The option –nodaemon option instructs Buildbot to skip daemonizing. The process will start in the foreground. It will only return to the command-line when it is stopped. restart
buildbot-worker restart [--nodaemon] BASEDIR

This restarts a worker which is already running. It is equivalent to a stop followed by a start.

The option –nodaemon option has the same meaning as for start. stop

This terminates the daemon worker running in the given directory.

buildbot stop BASEDIR

2.8. Resources

The Buildbot home page is

For configuration questions and general discussion, please use the buildbot-devel mailing list. The subscription instructions and archives are available at

The #buildbot channel on Freenode’s IRC servers hosts development discussion, and often folks are available to answer questions there, as well.

2.9. Optimization

If you’re feeling your Buildbot is running a bit slow, here are some tricks that may help you, but use them at your own risk.

2.9.1. Properties load speedup

For example, if most of your build properties are strings, you can gain an approx. 30% speedup if you put this snippet of code inside your master.cfg file:

def speedup_json_loads():
    import json, re

    original_decode = json._default_decoder.decode
    my_regexp = re.compile(r'^\[\"([^"]*)\",\s+\"([^"]*)\"\]$')
    def decode_with_re(str, *args, **kw):
        m = my_regexp.match(str)
            return list(m.groups())
        except Exception:
            return original_decode(str, *args, **kw)
    json._default_decoder.decode = decode_with_re


It patches json decoder so that it would first try to extract a value from JSON that is a list of two strings (which is the case for a property being a string), and would fallback to general JSON decoder on any error.

2.10. Plugin Infrastructure in Buildbot

New in version 0.8.11.

Plugin infrastructure in Buildbot allows easy use of components that are not part of the core. It also allows unified access to components that are included in the core.

The following snippet

from buildbot.plugins import kind

... kind.ComponentClass ...

allows to use a component of kind kind. Available kinds are:

workers, described in Workers
change source, described in Change Sources and Changes
schedulers, described in Schedulers
build steps, described in Build Steps
reporters (or reporter targets), described in Reporters
utility classes. For example, BuilderConfigBuild FactoriesChangeFilter and Locks are accessible through util.

Web interface plugins are not used directly: as described in web server configuration section, they are listed in the corresponding section of the web server configuration dictionary.


If you are not very familiar with Python and you need to use different kinds of components, start your master.cfg file with:

from buildbot.plugins import *

As a result, all listed above components will be available for use. This is what sample master.cfgfile uses.

2.10.1. Finding Plugins

Buildbot maintains a list of plugins at

2.10.2. Developing Plugins

Distribute a Buildbot Plug-In contains all necessary information for you to develop new plugins. Please edit to add a link to your plugin!

2.10.3. Plugins of note

Plugins were introduced in Buildbot-0.8.11, so as of this writing, only components that are bundled with Buildbot are available as plugins.

If you have an idea/need about extending Buildbot, head to How to package Buildbot plugins, create your own plugins and let the world now how Buildbot can be made even more useful.

2.11. Deployment

This page aims at describing the common pitfalls and best practices when deploying buildbot.

2.11.1. Using A Database Server

Buildbot uses the sqlite3 database backend by default. If you plan to host a lot of data, you may consider using a more suitable database server.

If you want to use a database server (e.g., MySQL or Postgres) as the database backend for your Buildbot, use option buildbot create-master –db to specify the connection string for the database, and make sure that the same URL appears in the db_url of the db parameter in your configuration file. Additional Requirements

Depending on the selected database, further Python packages will be required. Consult the SQLAlchemy dialect list for a full description. The most common choice for MySQL is mysqlclient. Any reasonably recent version should suffice.

The most common choice for Postgres is Psycopg Any reasonably recent version should suffice.

2.11.2. Maintenance

The buildmaster can be configured to send out email notifications when a worker has been offline for a while. Be sure to configure the buildmaster with a contact email address for each worker so these notifications are sent to someone who can bring it back online.

If you find you can no longer provide a worker to the project, please let the project admins know, so they can put out a call for a replacement.

The Buildbot records status and logs output continually, each time a build is performed. The status tends to be small, but the build logs can become quite large. Each build and log are recorded in a separate file, arranged hierarchically under the buildmaster’s base directory. To prevent these files from growing without bound, you should periodically delete old build logs. A simple cron job to delete anything older than, say, two weeks should do the job. The only trick is to leave the buildbot.tac and other support files alone, for which find’s -mindepth argument helps skip everything in the top directory. You can use something like the following (assuming builds are stored in ./builds/directory):

@weekly cd BASEDIR && find . -mindepth 2 i-path './builds/*' \
    -prune -o -type f -mtime +14 -exec rm {} \;
@weekly cd BASEDIR && find twistd.log* -mtime +14 -exec rm {} \;

Alternatively, you can configure a maximum number of old logs to be kept using the --log-countcommand line option when running buildbot-worker create-worker or buildbot create-master.

2.11.3. Troubleshooting

Here are a few hints on diagnosing common problems. Starting the worker

Cron jobs are typically run with a minimal shell (/bin/sh, not /bin/bash), and tilde expansion is not always performed in such commands. You may want to use explicit paths, because the PATH is usually quite short and doesn’t include anything set by your shell’s startup scripts (.profile.bashrc, etc). If you’ve installed buildbot (or other Python libraries) to an unusual location, you may need to add a PYTHONPATH specification (note that Python will do tilde-expansion on PYTHONPATH elements by itself). Sometimes it is safer to fully-specify everything:

@reboot PYTHONPATH=~/lib/python /usr/local/bin/buildbot \
    start /usr/home/buildbot/basedir

Take the time to get the @reboot job set up. Otherwise, things will work fine for a while, but the first power outage or system reboot you have will stop the worker with nothing but the cries of sorrowful developers to remind you that it has gone away. Connecting to the buildmaster

If the worker cannot connect to the buildmaster, the reason should be described in the twistd.loglogfile. Some common problems are an incorrect master hostname or port number, or a mistyped bot name or password. If the worker loses the connection to the master, it is supposed to attempt to reconnect with an exponentially-increasing backoff. Each attempt (and the time of the next attempt) will be logged. If you get impatient, just manually stop and re-start the worker.

When the buildmaster is restarted, all workers will be disconnected, and will attempt to reconnect as usual. The reconnect time will depend upon how long the buildmaster is offline (i.e. how far up the exponential backoff curve the workers have travelled). Again, buildbot-worker restart BASEDIR will speed up the process. Contrib Scripts

While some features of Buildbot are included in the distribution, others are only available in master/contrib/ in the buildbot-contrib source directory. The latest versions of such scripts are available at master/contrib.

2.12. Upgrading

This section describes the process of upgrading from old versions of Buildbot.

2.12.1. Upgrading to Nine

Upgrading a Buildbot instance from 0.8.x to 0.9.x may require a number of changes to the master configuration. Those changes are summarized here. If you are starting fresh with 0.9.0 or later, you can safely skip this section.

First important note is that Buildbot does not support an upgrade of a 0.8.x instance to 0.9.x. Notably the build data and logs will not be accessible anymore if you upgraded, thus the database migration scripts have been dropped.

You should not pip upgrade -U buildbot, but rather start from a clean virtualenv aside from your old master. You can keep your old master instance to serve the old build status.

Buildbot is now composed of several Python packages and Javascript UI, and the easiest way to install it is to run the following command within a virtualenv:

pip install 'buildbot[bundle]' Config File Syntax

In preparation for compatibility with Python 3, Buildbot configuration files no longer allow the print statement:

print "foo"

To fix, simply enclose the print arguments in parentheses:

print("foo") Plugins

Although plugin support was available in 0.8.12, its use is now highly recommended. Instead of importing modules directly in master.cfg, import the plugin kind from buildbot.plugins:

from buildbot.plugins import steps

Then access the plugin itself as an attribute:


See Plugin Infrastructure in Buildbot for more information. Web Status

The most prominent change is that the existing WebStatus class is now gone, replaced by the new wwwfunctionality.

Thus an html.WebStatus entry in c['status'] should be removed and replaced with configuration in c['www']`. For example, replace:

from buildbot.status import html
c['status'].append(html.WebStatus(http_port=8010, allowForce=True)


c['www'] = dict(port=8010,

See www for more information. Status Classes

Where in 0.8.x most of the data about a build was available synchronously, it must now be fetched dynamically using the Data API. All classes under the Python package buildbot.status should be considered deprecated. Many have already been removed, and the remainder have limited functionality. Any custom code which refers to these classes must be rewritten to use the Data API. Avoid the temptation to reach into the Buildbot source code to find other useful-looking methods!

Common uses of the status API are:

  • getBuild in a custom renderable
  • MailNotifier message formatters (see below for upgrade hints)
  • doIf functions on steps

Import paths for several classes under the buildbot.status package but which remain useful have changed. Most of these are now available as plugins (see above), but for the remainder, consult the source code. BuildRequest Merging

Buildbot 0.9.x has replaced the old concept of request merging (mergeRequests) with a more flexible request-collapsing mechanism. See collapseRequests for more information. Status Reporters

In fact, the whole c['status'] configuration parameter is gone.

Many of the status listeners used in the status hierarchy in 0.8.x have been replaced with “reporters” that are available as buildbot plugins. However, note that not all status listeners have yet been ported. See the release notes for details.

Including the "status" key in the configuration object will cause a configuration error. All reporters should be included in c['services'] as described in Reporters.

The available reporters as of 0.9.0 are

See the reporter index for the full, current list.

A few notes on changes to the configuration of these reporters:

  • MailNotifier argument messageFormatter should now be a buildbot.reporters.message.MessageFormatter, due to the removal of the status classes (see above), such formatters must be re-implemented using the Data API.
  • MailNotifier argument previousBuildGetter is not supported anymore
  • MailNotifier no longer forces SSL 3.0 when useTls is true.
  • GerritStatusPush callbacks slightly changed signature, and include a master reference instead of a status reference.
  • GitHubStatusPush now accepts a context parameter to be passed to the GitHub Status API.
  • buildbot.status.builder.Results and the constants buildbot.status.results.SUCCESS should be imported from the buildbot.process.results module instead. Steps

Buildbot-0.8.9 introduced “new-style steps”, with an asynchronous run method. In the remaining 0.8.x releases, use of new-style and old-style steps were supported side-by-side. In 0.9.x, old-style steps are emulated using a collection of hacks to allow asynchronous calls to be called from synchronous code. This emulation is imperfect, and you are strongly encouraged to rewrite any custom steps as New-Style Build Steps.

Note that new-style steps now “push” their status when it changes, so the describe method no longer exists. Identifiers

Many strings in Buildbot must now be identifiers. Identifiers are designed to fit easily and unambiguously into URLs, AMQP routes, and the like. An “identifier” is a nonempty unicode string of limited length, containing only ASCII alphanumeric characters along with - (dash) and _ (underscore), and not beginning with a digit

Unfortunately, many existing names do not fit this pattern.

The following fields are identifiers:

  • worker name (50-character)
  • builder name (70-character)
  • step name (50-character) Serving static files

Since version 0.9.0 Buildbot doesn’t use and don’t serve master’s public_html directory. You need to use third-party HTTP server for serving static files. Transition to “worker” terminology

Since version 0.9.0 of Buildbot “slave”-based terminology is deprecated in favor of “worker”-based terminology.

All identifiers, messages and documentation were updated to use “worker” instead of “slave”. Old API names are still available, but deprecated.

For details about changed API and how to control generated warnings see Transition to “worker” terminology. Other Config Settings

The default master.cfg file contains some new changes, which you should look over:

  • c['protocols'] = {'pb': {'port': 9989}} (the default port used by the workers)
  • Waterfall View: requires installation (pip install buildbot-waterfall-view) and configuration (c['www'] = { ..., 'plugins': {'waterfall_view': {} }). Build History

There is no support for importing build history from 0.8.x (where the history was stored on-disk in pickle files) into 0.9.x (where it is stored in the database). Data LifeTime

Buildbot Nine data being implemented fully in an SQL database, the buildHorizon feature had to be reworked. Instead of being number-of-things based, it is now time based. This makes more sense from a user perspective but makes it harder to predict the database average size. Please be careful to provision enough disk space for your database.

The old c['logHorizon'] way of configuring is not supported anymore. See JanitorConfigurator to learn how to configure. A new __Janitor builder will be created to help keep an eye on the cleanup activities. More Information

For minor changes not mentioned here, consult the release notes for the versions over which you are upgrading.

Buildbot-0.9.0 represents several years’ work, and as such we may have missed potential migration issues.

2.12.2. New-Style Build Steps

In Buildbot-0.9.0, many operations performed by BuildStep subclasses return a Deferred. As a result, custom build steps which call these methods will need to be rewritten.

Buildbot-0.8.9 supports old-style steps natively, while new-style steps are emulated. Buildbot-0.9.0 supports new-style steps natively, while old-style steps are emulated. Later versions of Buildbot will not support old-style steps at all. All custom steps should be rewritten in the new style as soon as possible.

Buildbot distinguishes new-style from old-style steps by the presence of a run method. If this method is present, then the step is a new-style step. Summary of Changes
  • New-style steps have a run method that is simpler to implement than the old start method.
  • Many methods are now asynchronous (return Deferreds), as they perform operations on the database.
  • Logs are now implemented by a completely different class. This class supports the same log-writing methods (addStderr and so on), although they are now asynchronous. However, it does not support log-reading methods such as getText. It was never advisable to handle logs as enormous strings. New-style steps should, instead, use a LogObserver or (in Buildbot-0.9.0) fetch log lines bit by bit using the data API.
  • buildbot.process.buildstep.LoggingBuildStep is deprecated and cannot be used in new-style steps. Mix in buildbot.process.buildstep.ShellMixin instead.
  • Step strings, derived by parameters like descriptiondescriptionDone, and descriptionSuffix, are no longer treated as lists. For backward compatibility, the parameters may still be given as lists, but will be joined with spaces during execution (using join_list). Backward Compatibility

Some hacks are in place to support old-style steps. These hacks are only activated when an old-style step is detected. Support for old-style steps will be dropped soon after Buildbot-0.9.0 is released.

  • The Deferreds from all asynchronous methods invoked during step execution are gathered internally. The step is not considered finished until all such Deferreds have fired, and is marked EXCEPTION if any fail. For logfiles, this is accomplished by means of a synchronous wrapper class.
  • Logfile data is available while the step is still in memory. This means that logs returned from step.getLog have the expected methods getTextreadlines and so on.
  • ShellCommand subclasses implicitly gather all stdio output in memory and provide it to the createSummary method. Rewriting start

If your custom buildstep implements the start method, then rename that method to run and set it up to return a Deferred, either explicitly or via inlineCallbacks. The value of the Deferred should be the result of the step (one of the codes in buildbot.process.results), or a Twisted failure instance to complete the step as EXCEPTION. The new run method should not call self.finished or self.failed, instead signalling the same via Deferred.

For example, the following old-style start method

def start(self):  ## old style
    cmd = remotecommand.RemoteCommand('stat', {'file': self.file })
    d = self.runCommand(cmd)
    d.addCallback(lambda res: self.convertResult(cmd))


def run(self):  ## new style
    cmd = remotecommand.RemoteCommand('stat', {'file': self.file })
    yield self.runCommand(cmd)
    defer.returnValue(self.convertResult(cmd)) Newly Asynchronous Methods

The following methods now return a Deferred:

Any custom code in a new-style step that calls these methods must handle the resulting Deferred. In some cases, that means that the calling method’s signature will change. For example

def summarize(self):  ## old-style
    for m in self.MESSAGES:
        if counts[m]:
            self.addCompleteLog(m, "".join(summaries[m]))
        self.setProperty("count-%s" % m, counts[m], "counter")

Is a synchronous function, not returning a Deferred. However, when converted to a new-style test, it must handle Deferreds from the methods it calls, so it must be asynchronous. Syntactically, inlineCallbacks makes the change fairly simple:

def summarize(self):  ## new-style
    for m in self.MESSAGES:
        if counts[m]:
            yield self.addCompleteLog(m, "".join(summaries[m]))
        self.setProperty("count-%s" % m, counts[m], "counter")

However, this method’s callers must now handle the Deferred that it returns. All methods that can be overridden in custom steps can return a Deferred. Properties

Good news! The API for properties is the same synchronous API as was available in old-style steps. Properties are handled synchronously during the build, and persisted to the database at completion of each step. Log Objects

Old steps had two ways of interacting with logfiles, both of which have changed.

The first is writing to logs while a step is executing. When using addCompleteLog or addHTMLLog, this is straightforward, except that in new-style steps these methods return a Deferred.

The second method is via buildbot.process.buildstep.BuildStep.addLog. In new-style steps, the returned object (via Deferred) has the following methods to add log content:

All of these methods now return Deferreds. None of the old log-reading methods are available on this object:

  • hasContents
  • getText
  • readLines
  • getTextWithHeaders
  • getChunks

If your step uses such methods, consider using a LogObserver instead, or using the Data API to get the required data.

The undocumented and unused subscribeConsumer method of logfiles has also been removed.

The subscribe method now takes a callable, rather than an instance, and does not support catchup. This method was primarily used by LogObserver, the implementation of which has been modified accordingly. Any other uses of the subscribe method should be refactored to use a LogObserver. Status Strings

The self.step_status.setText and setText2 methods have been removed. Similarly, the _describe and describe methods are not used in new-style steps. In fact, steps no longer set their status directly.

Instead, steps call buildbot.process.buildstep.BuildStep.updateSummary whenever the status may have changed. This method calls getCurrentSummary or getResultSummary as appropriate and update displays of the step’s status. Steps override the latter two methods to provide appropriate summaries. Statistics

Support for statistics has been moved to the BuildStep and Build objects. Calls to self.step_status.setStatistic should be rewritten as self.setStatistic.

2.12.3. Transition to “worker” terminology

Since version 0.9.0 of Buildbot “slave”-based terminology is deprecated in favor of “worker”-based terminology.

API change is done in backward compatible way, so old “slave”-containing classes, functions and attributes are still available and can be used. Old API support will be removed in the future versions of Buildbot.

Rename of API introduced in beta versions of Buildbot 0.9.0 done without providing fallback. See release notes for the list of breaking changes of private interfaces. Old names fallback settings

Use of obsolete names will raise Python warnings with categorybuildbot.worker_transition.DeprecatedWorkerAPIWarning. By default these warnings are printed in the application log. This behaviour can be changed by setting appropriate Python warnings settings via Python’s warnings module:

import warnings
from buildbot.worker_transition import DeprecatedWorkerAPIWarning
# Treat old-name usage as errors:
warnings.simplefilter("error", DeprecatedWorkerAPIWarning)

See Python’s warnings module documentation for complete list of available actions, in particular warnings can be disabled using "ignore" action.

It’s recommended to configure warnings inside buildbot.tac, before using any other Buildbot classes. Changed API

In general “Slave” and “Buildslave” parts in identifiers and messages were replaced with “Worker”; “SlaveBuilder” with “WorkerForBuilder”.

Below is the list of changed API (use of old names from this list will work). Note that some of these symbols are not included in Buildbot’s public API. Compatibility is provided as a convenience to those using the private symbols anyway.

Old name New name
buildbot.interfaces.IBuildSlave IWorker
buildbot.interfaces.NoSlaveError (private) left as is, but deprecated (it shouldn’t be used at all)
buildbot.interfaces.BuildSlaveTooOldError WorkerTooOldError
buildbot.interfaces.LatentBuildSlaveFailedToSubstantiate(private) LatentWorkerFailedToSubstantiate
buildbot.interfaces.ILatentBuildSlave ILatentWorker
buildbot.interfaces.ISlaveStatus (will be removed in 0.9.x) IWorkerStatus
buildbot.buildslave module with all contents buildbot.worker
buildbot.buildslave.AbstractBuildSlave buildbot.worker.AbstractWorker
buildbot.buildslave.AbstractBuildSlave.slavename (private) buildbot.worker.AbstractWorker.workername
buildbot.buildslave.AbstractLatentBuildSlave buildbot.worker.AbstractLatentWorker
buildbot.buildslave.BuildSlave buildbot.worker.Worker
buildbot.buildslave.ec2 buildbot.worker.ec2
buildbot.buildslave.ec2.EC2LatentBuildSlave buildbot.worker.ec2.EC2LatentWorker
buildbot.buildslave.libvirt buildbot.worker.libvirt
buildbot.buildslave.libvirt.LibVirtSlave buildbot.worker.libvirt.LibVirtWorker
buildbot.buildslave.openstack buildbot.worker.openstack
buildbot.buildslave.openstack.OpenStackLatentBuildSlave buildbot.worker.openstack.OpenStackLatentWorker
buildbot.config.MasterConfig.slaves workers
buildbot.config.BuilderConfig constructor keyword argumentslavename was renamed to workername
buildbot.config.BuilderConfig constructor keyword argumentslavenames was renamed to workernames
buildbot.config.BuilderConfig constructor keyword argumentslavebuilddir was renamed to workerbuilddir
buildbot.config.BuilderConfig constructor keyword argumentnextSlave was renamed to nextWorker
buildbot.config.BuilderConfig.slavenames workernames
buildbot.config.BuilderConfig.slavebuilddir workerbuilddir
buildbot.config.BuilderConfig.nextSlave nextWorker
buildbot.process.slavebuilder buildbot.process.workerforbuilder
buildbot.process.slavebuilder.AbstractSlaveBuilder buildbot.process.workerforbuilder.AbstractWorkerForBuilder
buildbot.process.slavebuilder.AbstractSlaveBuilder.slave buildbot.process.workerforbuilder.AbstractWorkerForBuilder.worker
buildbot.process.slavebuilder.SlaveBuilder buildbot.process.workerforbuilder.WorkerForBuilder
buildbot.process.slavebuilder.LatentSlaveBuilder buildbot.process.workerforbuilder.LatentWorkerForBuilder getWorkerName workername
buildbot.process.builder.enforceChosenSlave enforceChosenWorker
buildbot.process.builder.Builder.canStartWithSlavebuilder canStartWithWorkerForBuilder
buildbot.process.builder.Builder.attaching_slaves attaching_workers
buildbot.process.builder.Builder.slaves workers
buildbot.process.builder.Builder.addLatentSlave addLatentWorker
buildbot.process.builder.Builder.getAvailableSlaves getAvailableWorkers
buildbot.schedulers.forcesched.BuildslaveChoiceParameter WorkerChoiceParameter
buildbot.process.buildstep.BuildStep.buildslave buildbot.process.buildstep.BuildStep.worker (also it was moved from class static attribute to instance attribute)
buildbot.process.buildstep.BuildStep.setBuildSlave buildbot.process.buildstep.BuildStep.setWorker
buildbot.process.buildstep.BuildStep.slaveVersion buildbot.process.buildstep.BuildStep.workerVersion
buildbot.process.buildstep.BuildStep.slaveVersionIsOlderThan buildbot.process.buildstep.BuildStep.workerVersionIsOlderThan
buildbot.process.buildstep.BuildStep.checkSlaveHasCommand buildbot.process.buildstep.BuildStep.checkWorkerHasCommand
buildbot.process.buildstep.BuildStep.getSlaveName buildbot.process.buildstep.BuildStep.getWorkerName
buildbot.locks.SlaveLock buildbot.locks.WorkerLock
buildbot.locks.SlaveLock.maxCountForSlave buildbot.locks.WorkerLock.maxCountForWorker
buildbot.locks.SlaveLock constructor argument maxCountForSlavewas renamed maxCountForWorker
buildbot.steps.slave buildbot.steps.worker
buildbot.steps.slave.SlaveBuildStep buildbot.steps.worker.WorkerBuildStep
buildbot.steps.slave.CompositeStepMixin.getFileContentFromSlave buildbot.steps.worker.CompositeStepMixin.getFileContentFromWorker
buildbot.steps.transfer.FileUpload.slavesrc workersrc
buildbot.steps.transfer.FileUpload constructor argument slavesrc was renamed to workersrc
buildbot.steps.transfer.DirectoryUpload.slavesrc workersrc
buildbot.steps.transfer.DirectoryUpload constructor argument slavesrc was renamed to workersrc
buildbot.steps.transfer.MultipleFileUpload.slavesrcs workersrcs
buildbot.steps.transfer.MultipleFileUpload constructor argument slavesrcs was renamed to workersrcs
buildbot.steps.transfer.FileDownload.slavedest workerdest
buildbot.steps.transfer.FileDownload constructor argument slavedest was renamed to workerdest
buildbot.steps.transfer.StringDownload.slavedest workerdest
buildbot.steps.transfer.StringDownload constructor argument slavedest was renamed to workerdest
buildbot.steps.transfer.JSONStringDownload.slavedest workerdest
buildbot.steps.transfer.JSONStringDownload constructor argument slavedest was renamed to workerdest
buildbot.steps.transfer.JSONPropertiesDownload.slavedest workerdest
buildbot.steps.transfer.JSONPropertiesDownload constructor argument slavedest was renamed to workerdest
buildbot.process.remotecommand.RemoteCommand.buildslave worker Plugins

buildbot.buildslave entry point was renamed to buildbot.worker, new plugins should be updated accordingly.

Plugins that use old buildbot.buildslave entry point are still available in the configuration file in the same way, as they were in versions prior 0.9.0:

from buildbot.plugins import buildslave  # deprecated, use "worker" instead
w = buildslave.ThirdPartyWorker()

But also they available using new namespace inside configuration file, so its recommended to use buildbot.plugins.worker name even if plugin uses old entry points:

from buildbot.plugins import worker
# ThirdPartyWorker can be defined in using `buildbot.buildslave` entry
# point, this still will work.
w = worker.ThirdPartyWorker()

Other changes:

  • buildbot.plugins.util.BuildslaveChoiceParameter is deprecated in favor of WorkerChoiceParameter.
  • buildbot.plugins.util.enforceChosenSlave is deprecated in favor of enforceChosenWorker.
  • buildbot.plugins.util.SlaveLock is deprecated in favor of WorkerLock. BuildmasterConfig changes
  • c['slaves'] was replaced with c['workers']. Use of c['slaves'] will work, but is considered deprecated, and will be removed in the future versions of Buildbot.
  • Configuration key c['slavePortnum'] is deprecated in favor of c['protocols']['pb']['port']. Docker latent worker changes

In addition to class being renamed, environment variables that are set inside container SLAVENAME and SLAVEPASS were renamed to WORKERNAME and WORKERPASS accordingly. Old environment variable are still available, but are deprecated and will be removed in the future. EC2 latent worker changes

Use of default values of keypair_name and security_name constructor arguments of buildbot.worker.ec2.EC2LatentWorker is deprecated. Please specify them explicitly. steps.slave.SetPropertiesFromEnv changes

In addition to buildbot.steps.slave module being renamed to buildbot.steps.worker, default sourcevalue for SetPropertiesFromEnv was changed from "SlaveEnvironment" to "WorkerEnvironment". Local worker changes

Working directory for local workers were changed from master-basedir/slaves/name to master-basedir/workers/name. Worker Manager changes

slave_config function argument was renamed to worker_config. Properties
  • slavename property is deprecated in favor of workername property. Render of deprecated property will produce warning.

    buildbot.worker.AbstractWorker (previously buildbot.buildslave.AbstractBuildSlaveslavenameproperty source were changed from BuildSlave to Worker (deprecated)

    AbstractWorker now sets workername property with source Worker which should be used. Metrics
  • buildbot.process.metrics.AttachedSlavesWatcher was renamed tobuildbot.process.metrics.AttachedWorkersWatcher.
  • (previously metric measurement class name changed from BuildslaveManager to WorkerManager
  • buildbot.worker.manager.WorkerManager.managed_services_name (previously buildbot.buildslave.manager.BuildslaveManager.managed_services_name`) metric measurementmanaged service name changed from ``buildslaves to workers

Renamed events:

Old name New name
AbstractBuildSlave.attached_slaves AbstractWorker.attached_workers
BotMaster.attached_slaves BotMaster.attached_workers
BotMaster.slaveLost() BotMaster.workerLost()
BotMaster.getBuildersForSlave() BotMaster.getBuildersForWorker()
AttachedSlavesWatcher AttachedWorkersWatcher
attached_slaves attached_workers Database

Schema changes:

Old name New name
buildslaves table workers
builds.buildslaveid (not ForeignKey) column workerid (now ForeignKey)
configured_buildslaves table configured_workers
configured_buildslaves.buildslaveid (ForeignKey) column workerid
connected_buildslaves table connected_workers
connected_buildslaves.buildslaveid (ForeignKey) column workerid
buildslaves_name index workers_name
configured_slaves_buildmasterid index configured_workers_buildmasterid
configured_slaves_slaves index configured_workers_workers
configured_slaves_identity index configured_workers_identity
connected_slaves_masterid index connected_workers_masterid
connected_slaves_slaves index connected_workers_workers
connected_slaves_identity index connected_workers_identity
builds_buildslaveid index builds_workerid

List of database-related changes in API (fallback for old API is provided):

Old name New name
buildbot.db.buildslaves workers
buildbot.db.buildslaves.BuildslavesConnectorComponent buildbot.db.workers.WorkersConnectorComponent
buildbot.db.buildslaves.BuildslavesConnectorComponent.getBuildslaves(rewritten in nine) buildbot.db.workers.WorkersConnectorComponent.getWorkers
buildbot.db.connector.DBConnector.buildslaves buildbot.db.connector.DBConnector.workers usePTY changes

usePTY default value has been changed from slave-config to None (use of slave-config will still work, but discouraged). buildbot-worker

buildbot-slave package has been renamed to buildbot-worker.

buildbot-worker has backward incompatible changes and requires buildmaster >= 0.9.0b8. buildbot-slave from 0.8.x will work with both 0.8.x and 0.9.x versions of buildmaster, so there is no need to upgrade currently deployed buildbot-slaves during switch from 0.8.x to 0.9.x.

Master/worker compatibility table
master 0.8.x master 0.9.x
buildbot-slave yes yes
buildbot-worker no yes

buildbot-worker doesn’t support worker-side specification of usePTY (with --usepty command line switch of buildbot-worker create-worker), you need to specify this option on master side.

getSlaveInfo remote command was renamed to getWorkerInfo in buildbot-worker.

3. Buildbot Development

This chapter is the official repository for the collected wisdom of the Buildbot hackers. It is intended both for developers writing patches that will be included in Buildbot itself, and for advanced users who wish to customize Buildbot.

3.1. Development Quick-start

Buildbot is a python based application. It tries very hard to follow the python best practices, and to make is easy to dive into the code.

We won’t try to create a full step by step how to install python on whatever distribution. Basically what you need is just a python environment with maybe some native packages required by our dependencies. Because those dependencies sometimes change, we keep the most up to date list in the docker file we use to manage our CI (MetaBBotDockerFile).

If you are completely new to python, the best is to first follow the tutorials that would come when you type “python virtualenv for dummies” in your favorite search engine.

3.1.1. Create a Buildbot Python Environment

Buildbot uses Twisted trial to run its test suite.

Following is a quick shell session to put you on the right track, including running the test suite.

# the usual buildbot development bootstrap with git and virtualenv
git clone
cd buildbot

# helper script which creates the virtualenv for development
make virtualenv
. .venv/bin/activate

# now we run the test suite
trial buildbot

# find all tests that talk about mail
trial -n --reporter=bwverbose buildbot | grep mail

# run only one test module
trial buildbot.test.unit.test_reporters_mail

3.1.2. Create a JavaScript Frontend Environment

This section describes how to get set up quickly to hack on the JavaScript UI. It does not assume familiarity with Python, although a Python installation is required, as well as virtualenv. You will also need NodeJS, and npm installed. Prerequisites


Buildbot UI is only tested to build on node 4.x.x.

  • Install LTS release of node.js. is a good start for windows and osx

    For Linux, as node.js is evolving very fast, distros versions are often too old, and sometimes distro maintainers make incompatible changes (i.e naming node binary nodejs instead of node) For Ubuntu and other Debian based distros, you want to use following method:

    curl -sL | sudo bash -

    Please feel free to update this documentation for other distros. Know good source for Linux binary distribution is:

  • Install gulp globally. Gulp is the build system used for coffeescript development.

    sudo npm install -g gulp Hacking the Buildbot JavaScript

To effectively hack on the Buildbot JavaScript, you’ll need a running Buildmaster, configured to operate out of the source directory (unless you like editing minified JS).

thus you need to follow the Create a Buildbot Python Environment

This should have created an isolated Python environment in which you can install packages without affecting other parts of the system. You should see (.venv) in your shell prompt, indicating the sandbox is activated.

Next, install the Buildbot-WWW and Buildbot packages using --editable, which means that they should execute from the source directory.

make frontend

This will fetch a number of dependencies from pypi, the Python package repository. This will also fetch a bunch a bunch of node.js dependencies used for building the web application, and a bunch of client side js dependencies, with bower

Now you’ll need to create a master instance. For a bit more detail, see the Buildbot tutorial (First Run).

buildbot create-master .venv/testmaster
mv .venv/testmaster/master.cfg.sample .venv/testmaster/master.cfg
buildbot start .venv/testmaster

If all goes well, the master will start up and begin running in the background. As you just installed www in editable mode (aka ‘develop’ mode), did build the web site in prod mode, so the everything is minified, making it hard to debug.

When doing web development, you usually run:

cd www/base
gulp dev

This will compile the base webapp in development mode, and automatically rebuild when files change.

3.2. General Documents

This section gives some general information about Buildbot development.

3.2.1. Master Organization

Buildbot makes heavy use of Twisted Python’s support for services - software modules that can be started and stopped dynamically. Buildbot adds the ability to reconfigure such services, too - see Reconfiguration. Twisted arranges services into trees; the following section describes the service tree on a running master. BuildMaster Object

The hierarchy begins with the master, a buildbot.master.BuildMaster instance. Most other services contain a reference to this object in their master attribute, and in general the appropriate way to access other objects or services is to begin with self.master and navigate from there.

The master has a number of useful attributes:

buildbot.process.metrics.MetricLogObserver instance that handles tracking and reporting on master metrics.
buildbot.process.caches.CacheManager instance that provides access to object caches.
buildbot.pbmanager.PBManager instance that handles incoming PB connections, potentially on multiple ports, and dispatching those connections to appropriate components based on the supplied username.
buildbot.worker.manager.WorkerManager instance that provides wrapper around multiple master-worker protocols(e.g. PB) to unify calls for them from higher level code
buildbot.changes.manager.ChangeManager instance that manages the active change sources, as well as the stream of changes received from those sources. All active change sources are child services of this instance.

buildbot.process.botmaster.BotMaster instance that manages all of the workers and builders as child services.

The botmaster acts as the parent service for a buildbot.process.botmaster.BuildRequestDistributorinstance (at master.botmaster.brd) as well as all active workers (buildbot.worker.AbstractWorkerinstances) and builders (buildbot.process.builder.Builder instances).

buildbot.schedulers.manager.SchedulerManager instance that manages the active schedulers. All active schedulers are child services of this instance.
buildbot.process.users.manager.UserManagerManager instance that manages access to users. All active user managers are child services of this instance.
buildbot.db.connector.DBConnector instance that manages access to the buildbot database. See Database for more information.
buildbot.process.debug.DebugServices instance that manages debugging-related access – the manhole, in particular.
buildbot.status.master.Status instance that provides access to all status data. This instance is also the service parent for all status listeners.
This is the ID for this master, from the masters table. It is used in the database and messages to uniquely identify this master.

3.2.2. Buildbot Coding Style Documentation

Buildbot strongly encourages developers to document the methods, behavior, and usage of classes that users might interact with. However, this documentation should be in .rst files under master/docs/developer, rather than in docstrings within the code. For private methods or where code deserves some kind of explanatory preface, use comments instead of a docstring. While some docstrings remain within the code, these should be migrated to documentation files and removed as the code is modified.

Within the reStructuredText files, write with each English sentence on its own line. While this does not affect the generated output, it makes git diffs between versions of the documentation easier to read, as they are not obscured by changes due to re-wrapping. This convention is not followed everywhere, but we are slowly migrating documentation from the old (wrapped) style as we update it. Symbol Names

Buildbot follows PEP8 regarding the formatting of symbol names. Because Buildbot uses Twisted so heavily, and Twisted uses interCaps, this is not very consistently applied throughout the codebase.

The single exception to PEP8 is in naming of functions and methods. That is, you should spell methods and functions with the first character in lower-case, and the first letter of subsequent words capitalized, e.g., compareToOther or getChangesGreaterThan.

Symbols used as parameters to functions used in configuration files should use underscores.

In summary, then:

Symbol Type Format
Methods interCaps
Functions interCaps
Function Arguments under_scores
API method Arguments interCaps
Classes InitialCaps
Variables under_scores
Constants ALL_CAPS Twisted Idioms

Programming with Twisted Python can be daunting. But sticking to a few well-defined patterns can help avoid surprises.

Prefer to Return Deferreds

If you’re writing a method that doesn’t currently block, but could conceivably block sometime in the future, return a Deferred and document that it does so. Just about anything might block - even getters and setters!

Helpful Twisted Classes

Twisted has some usefu