Welcome to Buildbot capability’s documentation!


This package for buildbot >= 0.9 allows to declare that workers have capabilities, and produce BuilderConfig instances accordingly.

  • capabilities have a name (e.g. ‘postgresql’), an optional version (9.5) and optional additional parameters (such as port=5433)
  • one declares what are each worker’s capabilities as part of the worker config. A given capability name can occur on a worker several times, but a given (name, version) must appear exactly once.
  • it allows to express that a given build requires a given capability (e.g, access to a docker registry, presence of some helper program)
  • it can spawn several BuilderConfigs according to available capabilities on the full swarm, in a configurable way (e.g., one for each postgresql version greater than 9.3 or for 9.1)
  • at build time, the optional capability parameters are available as properties, so that, e.g., a build running integration tests against postgresql 9.5 would be able to use the right port (5433 in the example above) to access the database.

Complete example

In this example, we’ll show how to spawn build variants according to Python and PostgreSQL versions.

Worker capabilities are expressed in a big property:

from buildbot.plugins import worker
Worker = worker.Worker

c = BuildMasterConfig
c['workers'] = [Worker('wk1', 'pwd', properties={'capability':
  {'postgresql': {'9.2': {},
                  '9.3': {'port': '5433', 'bin': '/usr/lib/pg93'},
                  '9.4': {'port': '5434', 'bin': '/usr/lib/pg94'}
   'python': {'2.7': {},
              '2.6': {'bin': '/usr/local/bin/python2.6'},
   'ssh_key': None,   # this one is just a marker, no versions, no options

We need to supply information about how to use some of these capabilities:

capabilities = {
    'python': {
        'version_prop': 'py_version',
        'abbrev': 'py',
        'environ': {'PYTHONBIN': '%(cap(bin):-python)s'},
    'postgresql': {
        'version_prop': 'pg_version',
        'abbrev': 'pg',
        'environ': {'PGPORT': '%(cap(port):-)s',
                    'PATH': '%(cap(bin):-)s',

Now we are ready to dispatch a BuildFactory:

from anybox.buildbot.capability.dispatcher import BuilderDispatcher
from anybox.buildbot.capability.version import Version, VersionFilter
dispatcher = BuilderDispatcher(c['workers'], capabilities)
factory = BuildFactory()

If we need to use information about used capabilities within the build, we can add a special step:

env = dispatcher.set_properties_make_environ(
    ('python', 'postgresql')

The subsequent build steps can then access information about capability versions and options as properties py_version, pg_version, but also cap_pg_port, cap_python_bin, and the returned env is a ready-made dict with Interpolate values, that can be used for environment variables.

Now let’s create the BuilderConfig instances:

configs = dispatcher.make_builders(
    'bname', factory,
    build_for=[VersionFilter('postgresql', ['>', Version(9, 2)]),
               VersionFilter('python', ()),
    build_requires=[VersionFilter('ssh_key', ())]

The configured builders in that example will have names such as bname-pg9.3-py2.7 for all available PostgreSQL versions greater than 9.2 and all available Python version.

To each one, all the workers that have the ssh_key capability and the selected Python and PostgreSQL versions will be attached.

Of course this is far more streamlined if called through a layer implementing a declarative configuration.

This package does not supply such a declarative layer, because that may involve much more that capability filtering and dispatching. There are facilities to parse versions and version filters from strings (see anybox.buildbot.capability.version), yet the format is somewhat naive and should not be considered to be stable.

Indices and tables