Question

Caution

Buildbot no longer supports Python 2.7 on the Buildbot master.

2.5.9. Build Factories

Each Builder is equipped with a build factory, which defines the steps used to perform a 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.

Note

Build factories are used with builders, and are not added directly to the buildmaster configuration dictionary.

• A 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):

  c['builders'].append(
      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:

  f.addSteps(all_steps)
  

  Attributes

  The following attributes can be set on a build factory after it is created, e.g.,

  f = util.BuildFactory()
  f.useProgress = False
  

  useProgress

  (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.

  workdir

  (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.

  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, let’s say you have a script checked in into your source tree called build.sh. 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 ./build.sh --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)
          super().__init__(**kwargs)
          self.observer = logobserver.BufferLogObserver()
          self.addLogObserver('stdio', self.observer)
  
      def extract_stages(self, stdout):
          stages = []
          for line in stdout.split('\n'):
              stage = str(line.strip())
              if stage:
                  stages.append(stage)
          return stages
  
      @defer.inlineCallbacks
      def run(self):
          # run './build.sh --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
              self.build.addStepsAfterCurrentStep([
                  steps.ShellCommand(name=stage, command=["./build.sh", "--run-stage", stage])
                  for stage in self.extract_stages(self.observer.getStdout())
              ])
  
          return result
  
  f = util.BuildFactory()
  f.addStep(steps.Git(repourl=repourl))
  f.addStep(GenerateStagesCommand(
      name="Generate build stages",
      command=["./build.sh", "--list-stages"],
      haltOnFailure=True))
  

  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.

  GNUAutoconf

  class buildbot.process.factory.GNUAutoconf

  class buildbot.process.factory.BasicBuildFactory

  class buildbot.process.factory.QuickBuildFactory

  class buildbot.process.factory.BasicSVN

  class buildbot.process.factory.CPAN

  class buildbot.process.factory.Distutils

  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 ./setup.py build
  % PYTHONPATH=build/lib.linux-i686-2.3 trial -v PROJECTNAME.test
  % python ./setup.py 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.

  Arguments:

  testpath

  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.

  python

  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'].

  trial

  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.

  trialMode

  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.

  trialArgs

  A list of arguments to pass to trial, available to turn on any extra flags you like. Defaults to [].

  tests

  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.

  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.

  recurse

  If True, tells Trial (with the --recurse argument) to look in all subdirectories for additional test cases.

  reactor

  which reactor to use, like ‘gtk’ or ‘java’. If not provided, the Twisted’s usual platform-dependent default is used.

  randomly

  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.