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.

name

Each Scheduler must have a unique name. This is used in status displays, and is also available in the build property scheduler.

builderNames

This is the set of builders which this scheduler should trigger, specified as a list of names (strings).

properties

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' : [ 'zorro@company.com', 'silver@company.com' ] })

fileIsImportant

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

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.

onlyImportant

A boolean that, when True, only adds important changes to the buildset as sepcified 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.

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.

Change Filters

class buidbot.changes.filter.ChangeFilter

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.changes.filter import ChangeFilter
my_filter = ChangeFilter(
    project_re="^baseproduct/.*",
    branch="devel")

and then add it to a scheduler with the change_filter parameter:

sch = SomeSchedulerClass(...,
    change_filter=my_filter)

There are four attributes of changes on which you can filter:

project

the project string, as defined by the ChangeSource.

repository

the repository in which this change occurred.

branch

the branch on which this change occurred. Note that 'trunk' or 'master' is often denoted by None.

category

the category, again as defined by the ChangeSource.

For each attribute, the filter can look for a single, specific value:

my_filter = ChangeFilter(project = 'myproject')

or accept any of a set of values:

my_filter = ChangeFilter(project = ['myproject', 'jimsproject'])

or apply a regular expression, using the attribute name with a "_re" suffix:

my_filter = ChangeFilter(category_re = '.*deve.*')
# or, to use regular expression flags:
import re
my_filter = ChangeFilter(category_re = re.compile('.*deve.*', re.I))

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 = 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
filter_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).

SingleBranchScheduler

class buildbot.schedulers.basic.SingleBranchScheduler

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. The Scheduler accepts a fileIsImportant function which can be used to ignore some Changes if they do not affect any important files.

The arguments to this scheduler are:

name

builderNames

properties

fileIsImportant

change_filter

onlyImportant

See Configuring Schedulers.

treeStableTimer

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.

fileIsImportant

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.

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.

Note

None is a keyword, not a string, so write None and not "None".

Example:

from buildbot.schedulers.basic  import SingleBranchScheduler
from buildbot.changes import filter
quick = SingleBranchScheduler(name="quick",
                    change_filter=filter.ChangeFilter(branch='master'),
                    treeStableTimer=60,
                    builderNames=["quick-linux", "quick-netbsd"])
full = SingleBranchScheduler(name="full",
                    change_filter=filter.ChangeFilter(branch='master'),
                    treeStableTimer=5*60,
                    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 by these schedulers. Each scheduler triggers a different set of Builders, referenced by name.

class buildbot.schedulers.basic.Scheduler

class buildbot.scheduler.Scheduler

The old names for this scheduler, buildbot.scheduler.Scheduler and buildbot.schedulers.basic.Scheduler, are deprecated in favor of the more accurate name buildbot.schedulers.basic.SingleBranchScheduler.

AnyBranchScheduler

This scheduler uses a tree-stable-timer like the default one, but uses a separate timer for each branch.

The arguments to this scheduler are:

name

builderNames

properties

fileIsImportant

change_filter

onlyImportant

See Configuring Schedulers.

treeStableTimer

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 scheduler.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 ChangeSource, 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:

name

builderNames

properties

See Configuring Schedulers.

upstream

The upstream scheduler to watch. Note that this is an instance, not the name of the scheduler.

Example:

from buildbot.schedulers import basic
tests = basic.SingleBranchScheduler("just-tests", None, 5*60,
                                    ["full-linux", "full-netbsd", "full-OSX"])
package = basic.Dependent(name="build-package",
                          upstream=tests, # <- no quotes!
                          builderNames=["make-tarball", "make-deb", "make-rpm"])
c['schedulers'] = [tests, package]

Periodic Scheduler

class buildbot.schedulers.timed.Periodic

This simple scheduler just triggers a build every N seconds.

The arguments to this scheduler are:

name

builderNames

properties

onlyImportant

periodicBuildTimer

The time, in seconds, after which to start a build.

Example:

from buildbot.schedulers import timed
nightly = timed.Periodic(name="daily",
                builderNames=["full-solaris"],
                periodicBuildTimer=24*60*60)
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 minute, hour, dayOfMonth, month, 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:

name

builderNames

properties

fileIsImportant

change_filter

onlyImportant

See Configuring Schedulers. Note that fileIsImportant and change_filter are only relevant if onlyIfChanged is True.

onlyIfChanged

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.

branch

(required) The branch to build when the time comes. Remember that a value of None here means the default branch, and will not match other branches!

minute

The minute of the hour on which to start the build. This defaults to 0, meaning an hourly build.

hour

The hour of the day on which to start the build, in 24-hour notation. This defaults to *, meaning every hour.

dayOfMonth

The day of the month to start a build. This defauls to *, meaning every day.

month

The month in which to start the build, with January = 1. This defaults to *, meaning every month.

dayOfWeek

The day of the week to start a build, with Monday = 0. This defauls 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.schedulers import timed
c['schedulers'].append(
    timed.Nightly(name='nightly',
        branch='master',
        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:

c['schedulers'].append(
    timed.Nightly(name='BeforeWork',
         branch=`default`,
         builderNames=['builder1'],
         dayOfWeek=0,
         hour=[6,8],
         minute=23,
         onlyIfChanged=True))

The following runs a build every two hours, using Python's range function:

c.schedulers.append(
    timed.Nightly(name='every2hours',
        branch=None, # default branch
        builderNames=['builder1'],
        hour=range(0, 24, 2)))

Finally, this example will run only on December 24th:

c['schedulers'].append(
    timed.Nightly(name='SleighPreflightCheck',
        branch=None, # default branch
        builderNames=['flying_circuits', 'radar'],
        month=12,
        dayOfMonth=24,
        hour=12,
        minute=0))

Try Schedulers

class buildbot.schedulers.trysched.Try_Jobdir

class buildbot.schedulers.trysched.Try_Userpass

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 buildslave 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 buildslaves. The usual force-build control channels can waste buildslave 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 buildslaves 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 buildslave 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.schedulers.trysched import Try_Jobdir
s = Try_Jobdir(name="try1",
               builderNames=["full-linux", "full-netbsd", "full-OSX"],
               jobdir="jobdir")
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.

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 addtional 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 buildslave accounts depends upon it:

from buildbot.schedulers.trysched import Try_Userpass
s = Try_Userpass(name="try2",
                 builderNames=["full-linux", "full-netbsd", "full-OSX"],
                 port=8031,
                 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

class buildbot.schedulers.triggerable.Triggerable

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 a 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 buildslaves.

The parameters are just the basics:

name

builderNames

properties

See Configuring Schedulers.

This class is only useful in conjunction with the Trigger step. Here is a fully-worked example:

from buildbot.schedulers import basic, timed, triggerable
from buildbot.process import factory
from buildbot.steps import trigger

checkin = basic.SingleBranchScheduler(name="checkin",
            branch=None,
            treeStableTimer=5*60,
            builderNames=["checkin"])
nightly = timed.Nightly(name='nightly',
            branch=None,
            builderNames=['nightly'],
            hour=3,
            minute=0)

mktarball = triggerable.Triggerable(name="mktarball",
                builderNames=["mktarball"])
build = triggerable.Triggerable(name="build-all-platforms",
                builderNames=["build-all-platforms"])
test = triggerable.Triggerable(name="distributed-test",
                builderNames=["distributed-test"])
package = triggerable.Triggerable(name="package-all-platforms",
                builderNames=["package-all-platforms"])

c['schedulers'] = [mktarball, checkin, nightly, build, test, package]

# on checkin, make a tarball, build it, and test it
checkin_factory = factory.BuildFactory()
checkin_factory.addStep(trigger.Trigger(schedulerNames=['mktarball'],
                                       waitForFinish=True))
checkin_factory.addStep(trigger.Trigger(schedulerNames=['build-all-platforms'],
                                   waitForFinish=True))
checkin_factory.addStep(trigger.Trigger(schedulerNames=['distributed-test'],
                                  waitForFinish=True))

# and every night, make a tarball, build it, and package it
nightly_factory = factory.BuildFactory()
nightly_factory.addStep(trigger.Trigger(schedulerNames=['mktarball'],
                                       waitForFinish=True))
nightly_factory.addStep(trigger.Trigger(schedulerNames=['build-all-platforms'],
                                   waitForFinish=True))
nightly_factory.addStep(trigger.Trigger(schedulerNames=['package-all-platforms'],
                                     waitForFinish=True))