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2.5.3. Change Sources and Changes

A 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.

A 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.

2.5.3.1. 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 p4base and 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. git rev-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.

Comparison

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.

2.5.3.2. 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.

CVS

SVN

Darcs

Mercurial

Bzr (the newer Bazaar)

Git

Repo/Gerrit

Monotone

  • 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.

2.5.3.3. 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.

2.5.3.4. 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",
                                              prefix="/trunk/")

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 buildmaster@example.org). 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. foo@example.org account has control over every email address at example.org which begins with “foo”, such that email addressed to account-foo@example.org can be delivered to a different destination than account-bar@example.org. 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 foo-buildmaster@example.org to the buildmaster, and retain foo@example.org for your own use.

Using Maildirs

A maildir is a simple directory structure originally developed for qmail that allows safe atomic update without locking. Create a base directory with three subdirectories: new, tmp, 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
PATH=/usr/bin:/usr/local/bin
MAILDIR=$HOME/Mail
LOGFILE=.procmail_log
SHELL=/bin/sh

:0
*
new

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

!/usr/bin/procmail

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:

CVS
Buildbot CVS MailNotifier
CVSMaildirSource
SVN
svnmailer
http://opensource.perlig.de/en/svnmailer/
commit-email.pl
SVNCommitEmailMaildirSource
Bzr
Launchpad
BzrLaunchpadEmailMaildirSource
Mercurial
NotifyExtension
https://www.mercurial-scm.org/wiki/NotifyExtension
Git
post-receive-email
http://git.kernel.org/?p=git/git.git;a=blob;f=contrib/hooks/post-receive-email;hb=HEAD

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.

CVSMaildirSource

class buildbot.changes.mail.CVSMaildirSource

This parser works with the master/contrib/buildbot_cvs_mail.py 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 buildbot_cvs_mail.py

CVS must be configured to invoke the buildbot_cvs_mail.py 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/buildbot_cvs_mail.py --cvsroot :ext:example.com:/cvsroot -e buildbot -P SomeModule %@{sVv@}

Note

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 buildbot_cvs_mail.py 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 buildbot_cvs_mail.py --help for more information on the available options.

SVNCommitEmailMaildirSource

class buildbot.changes.mail.SVNCommitEmailMaildirSource

SVNCommitEmailMaildirSource parses message sent out by the commit-email.pl 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")

BzrLaunchpadEmailMaildirSource

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)

2.5.3.5. 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 PBChangeSource, you 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.

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

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.c instead 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/bzr_buildbot.py 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 https://launchpad.net/pqm) environment, the user that commits is the Patch Queue Manager, and the user that committed the parent revision 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.

Note

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.

[chroot-*:///var/local/myrepo/mybranch]
buildbot_on = change
buildbot_server = localhost

2.5.3.6. P4Source

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

p4port
The Perforce server to connect to (as host:port).
p4user
The Perforce user.
p4passwd
The Perforce password.
p4base
The base depot path to watch, without the trailing ‘/…’.
p4bin
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.
split_file
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.
pollInterval
How often to poll, in seconds. Defaults to 600 (10 minutes).
project
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.
pollAtLaunch
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
histmax
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.
encoding
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.
server_tz
The timezone of the Perforce server, using the usual timezone format (e.g: "Europe/Stockholm") in case it’s not in UTC.
use_tickets
Set to True to use ticket-based authentication, instead of passwords (but you still need to specify p4passwd).
ticket_login_interval
How often to get a new ticket, in seconds, when use_tickets is enabled. Defaults to 86400 (24 hours).
revlink
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’‘)
resolvewho
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 P4PORT, P4USER, 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

2.5.3.7. 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:

repourl

The base URL path to watch, like svn://svn.twistedmatrix.com/svn/Twisted/trunk, or http://divmod.org/svn/Divmo/, 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.

split_file

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.

project
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.
svnuser
An optional string parameter. If set, the option –user argument will be added to all svn commands. 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.
svnpasswd
Like svnuser, this will cause a option –password argument to be passed to all svn commands. Can be a Secret.
pollInterval
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.
pollAtLaunch
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
histmax
The maximum number of changes to inspect at a time. Every pollInterval seconds, the SVNPoller asks 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.
svnbin
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.
revlinktmpl
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.
cachepath
If specified, this is a pathname of a cache file that SVNPoller will use to store its state between restarts of the master.
extra_args
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(
    repourl="svn://svn.twistedmatrix.com/svn/Twisted/trunk",
    split_file=util.svn.split_file_alwaystrunk)

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(
    repourl="https://amanda.svn.sourceforge.net/svnroot/amanda/amanda",
    split_file=util.svn.split_file_branches)

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(
    repourl="https://amanda.svn.sourceforge.net/svnroot/amanda/",
    split_file=util.svn.split_file_projects_branches)

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.

2.5.3.8. Bzr Poller

If you cannot insert a Bzr hook in the server, you can use the BzrPoller. To use it, put master/contrib/bzr_buildbot.py 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 bzr_buildbot.py file to the same directory as master.cfg
from bzr_buildbot import BzrPoller

c['change_source'] = BzrPoller(
    url='bzr://hostname/my_project',
    poll_interval=300)

The BzrPoller parameters are:

url
The URL to poll.
poll_interval
The number of seconds to wait between polls. Defaults to 10 minutes.
branch_name
Any value to be used as the branch name. Defaults to None, or specify a string, or specify the constants from bzr_buildbot.py SHORT or FULL to get the short branch name or full branch address.
blame_merge_author
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 https://launchpad.net/pqm) 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.

2.5.3.9. GitPoller

If you cannot take advantage of post-receive hooks as provided by master/contrib/git_buildbot.py 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.

Note

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:

repourl
the git-url that describes the remote repository, e.g. git@example.com:foobaz/myrepo.git (see the git fetch help for more info on git-url formats)
branches

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.
branch
accepts a single branch name to fetch. Exists for backwards compatibility with old configurations.
pollInterval
interval in seconds between polls, default is 10 minutes
pollAtLaunch
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
buildPushesWithNoCommits
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).
gitbin
path to the Git binary, defaults to just 'git'
category
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.
project
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.
usetimestamps
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)
encoding
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.
workdir
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.
only_tags
Determines if the GitPoller should poll for new tags in the git repository.
sshPrivateKey
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.
sshHostKey
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='git@example.com:foobaz/myrepo.git',
                                       branches=['master', 'great_new_feature'])

2.5.3.10. 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:

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

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.

pollInterval
interval in seconds between polls, default is 10 minutes
pollAtLaunch
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
hgbin
path to the Mercurial binary, defaults to just 'hg'
category
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.
project
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.
usetimestamps
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)
encoding
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='http://hg.example.org/projects/myrepo',
                                      branch='great_new_feature',
                                      workdir='hg-myrepo')

2.5.3.11. GitHubPullrequestPoller

class buildbot.changes.github.GitHubPullrequestPoller

This GitHubPullrequestPoller periodically polls the GitHub API for new or updated pull requests. The author, revision, revlink, branch 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:

owner
The owner of the GitHub repository. This argument is required.
repo
The name of the GitHub repository. This argument is required.
branches
List of branches to accept as base branch (e.g. master). Defaults to None and accepts all branches as base.
pollInterval
Poll interval between polls in seconds. Default is 10 minutes.
pollAtLaunch
Whether to poll on startup of the buildbot master. Default is False and first poll will occur pollInterval seconds after the master start.
category
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.
baseURL
GitHub API endpoint. Default is https://api.github.com.
pullrequest_filter
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.
token
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.
repository_type
Set which type of repository link will be in the repository property. Possible values https, svn, git or svn. This link can then be used in a Source Step to checkout the source.
magic_link
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 GitHub source to pull from the special branch in the base repository. Default is False.
github_property_whitelist
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.

2.5.3.12. 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:

owner
The owner of the Bitbucket repository. All Bitbucket Urls are of the form https://bitbucket.org/owner/slug/.
slug
The name of the Bitbucket repository.
branch
A single branch or a list of branches which should be processed. If it is None (the default) all pull requests are used.
pollInterval
Interval in seconds between polls, default is 10 minutes.
pollAtLaunch
Determines when the first poll occurs. True = immediately on launch, False = wait for one pollInterval (default).
category
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.
project
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.
pullrequest_filter
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.
usetimestamps
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)
encoding
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(
    owner='myname',
    slug='myrepo',
  )

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(
    owner='myname',
    slug='myrepo',
    branch='mybranch',
    project='myproject',
    pullrequest_filter=lambda pr : approve_filter(pr,3),
    pollInterval=600,
)

Warning

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

2.5.3.13. 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:

gerritserver
the dns or ip that host the Gerrit ssh server
gerritport
the port of the Gerrit ssh server
username
the username to use to connect to Gerrit
identity_file
ssh identity file to for authentication (optional). Pay attention to the ssh passphrase
handled_events
event to be handled (optional). By default processes patchset-created and ref-updated
debug
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:

patchset-created
A change is proposed for review. Automatic checks like checkpatch.pl 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.
ref-updated
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.

Warning

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:

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

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

event.refUpdate.newRev
New Git commit ID (after merger)
event.refUpdate.oldRev
Previous Git commit ID (before merger)
event.refUpdate.project
Project that was updated
event.refUpdate.refName
Branch that was updated
event.submitter.email
Submitter’s email (merger responsible)
event.submitter.name
Submitter’s name (merger responsible)
event.type
Event type (ref-updated)
event.submitter.email
Submitter’s email (merger responsible)
event.submitter.name
Submitter’s name (merger responsible)

A configuration for this source might look like:

from buildbot.plugins import changes

c['change_source'] = changes.GerritChangeSource(
    "gerrit.example.com",
    "gerrit_user",
    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.

2.5.3.14. 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:

baseURL
the HTTP url where to find Gerrit
auth
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.
handled_events
event to be handled (optional). By default processes patchset-created and ref-updated
pollInterval
interval in seconds between polls, default is 30 seconds
pollAtLaunch
Determines when the first poll occurs. True = immediately on launch (default), False = wait for one pollInterval.
gitBaseURL
The git URL where Gerrit is accessible via git+ssh protocol
debug
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.

2.5.3.15. 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
schedulers.AnyBranchScheduler(name="main-precommit",
                              change_filter=util.GerritChangeFilter(branch="main",
                                                                    eventtype="patchset-created"),
                              treeStableTimer=15*60,
                              builderNames=["main-precommit"])

# this scheduler will create builds when a patch is merged in the "main" branch
# for post-commit tests
schedulers.AnyBranchScheduler(name="main-postcommit",
                              change_filter=util.GerritChangeFilter("main", "ref-updated"),
                              treeStableTimer=15*60,
                              builderNames=["main-postcommit"])

2.5.3.16. 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

A 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.

2.5.4.1. 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.

2.5.4.2. 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.

2.5.4.3. Comments

The Change also has a comments attribute, which is a string containing any checkin comments.

2.5.4.4. 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.

2.5.4.5. 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.

2.5.4.6. Codebase

This attribute specifies the codebase to which this change was made. As described in source stamps section, 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.

2.5.4.7. 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.

CVS
revision is the seconds since the epoch as an integer.
SVN
revision is the revision number
Darcs
revision is a large string, the output of darcs changes --context
Mercurial
revision is a short string (a hash ID), the output of hg identify
P4
revision is the transaction number
Git
revision is a short string (a SHA1 hash), the output of e.g. git rev-parse

2.5.4.8. 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.

CVS
branch=’warner-newfeature’, files=[‘src/foo.c’]
SVN
branch=’branches/warner-newfeature’, files=[‘src/foo.c’]
Darcs
branch=’warner-newfeature’, files=[‘src/foo.c’]
Mercurial
branch=’warner-newfeature’, files=[‘src/foo.c’]
Git
branch=’warner-newfeature’, files=[‘src/foo.c’]
Monotone
branch=’warner-newfeature’, files=[‘src/foo.c’]

2.5.4.9. 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.