BuildSteps
==========
.. py:module:: buildbot.process.buildstep
There are a few parent classes that are used as base classes for real
buildsteps. This section describes the base classes. The "leaf" classes are
described in :doc:`../manual/cfg-buildsteps`.
BuildStep
---------
.. py:class:: BuildStep(name, locks, haltOnFailure, flunkOnWarnings, flunkOnFailure, warnOnWarnings, warnOnFailure, alwaysRun, progressMetrics, useProgress, doStepIf)
All constructor arguments must be given as keyword arguments. Each
constructor parameter is copied to the corresponding attribute.
.. py:attribute:: name
The name of the step.
.. py:attribute:: locks
List of locks for this step; see :ref:`Interlocks`.
.. py:attribute:: progressMetrics
List of names of metrics that should be used to track the progress of
this build, and build ETA's for users. This is generally set in the
.. py:attribute:: useProgress
If true (the default), then ETAs will be calculated for this step using
progress metrics. If the step is known to have unpredictable timing
(e.g., an incremental build), then this should be set to false.
.. py:attribute:: doStepIf
A callable to determine whether this step should be executed. See
:ref:`Buildstep-Common-Parameters` for details.
The following attributes affect the behavior of the containing build:
.. py:attribute:: haltOnFailure
If true, the build will halt on a failure of this step, and not execute
subsequent tests (except those with ``alwaysRun``).
.. py:attribute:: flunkOnWarnings
If true, the build will be marked as a failure if this step ends with
warnings.
.. py:attribute:: flunkOnFailure
If true, the build will be marked as a failure if this step fails.
.. py:attribute:: warnOnWarnings
If true, the build will be marked as warnings, or worse, if this step
ends with warnings.
.. py:attribute:: warnOnFailure
If true, the build will be marked as warnings, or worse, if this step
fails.
.. py:attribute:: alwaysRun
If true, the step will run even if a previous step halts the build with
``haltOnFailure``.
A step acts as a factory for more steps. See
:ref:`Writing-BuildStep-Constructors` for advice on writing subclass
constructors. The following methods handle this factory behavior.
.. py:method:: addFactoryArguments(..)
Add the given keyword arguments to the arguments used to create new
step instances;
.. py:method:: getStepFactory()
:returns: tuple of (class, keyword arguments)
Get a factory for new instances of this step. The step can be created
by calling the class with the given keyword arguments.
A few important pieces of information are not available when a step is
constructed, and are added later. These are set by the following methods;
the order in which these methods are called is not defined.
.. py:method:: setBuild(build)
:param build: the :class:`~buildbot.process.build.Build` instance
controlling this step.
This method is called during setup to set the build instance
controlling this slave. Subclasses can override this to get access to
the build object as soon as it is available. The default
implementation sets the :attr:`build` attribute.
.. py:attribute:: build
The build object controlling this step.
.. py:method:: setBuildSlave(build)
:param build: the :class:`~buildbot.buildslave.BuildSlave` instance on
which this step will run.
Similarly, this method is called with the build slave that will run
this step. The default implementation sets the :attr:`buildslave`
attribute.
.. py:attribute:: buildslave
The build slave that will run this step.
.. py:method:: setDefaultWorkdir(workdir)
:param workdir: the default workdir, from the build
This method is called at build startup with the default workdir for the
build. Steps which allow a workdir to be specified, but want to
override it with the build's default workdir, can use this method to
apply the default.
.. py:method:: setStepStatus(status)
:param status: step status
:type status: :class:`~buildbot.status.buildstep.BuildStepStatus`
This method is called to set the status instance to which the step
should report. The default implementation sets :attr:`step_status`.
.. py:attribute:: step_status
The :class:`~buildbot.status.buildstep.BuildStepStatus` object tracking
the status of this step.
.. py:method:: setupProgress()
This method is called during build setup to give the step a chance to
set up progress tracking. It is only called if the build has
:attr:`useProgress` set. There is rarely any reason to override this
method.
.. py:attribute:: progress
If the step is tracking progress, this is a
:class:`~buildbot.status.progress.StepProgress` instance performing
that task.
Exeuction of the step itself is governed by the following methods and attributes.
.. py:method:: startStep(remote)
:param remote: a remote reference to the slave-side
:class:`~buildslave.bot.SlaveBuilder` instance
:returns: Deferred
Begin the step. This is the build's interface to step execution.
Subclasses should override :meth:`start` to implement custom behaviors.
The method returns a Deferred that fires when the step finishes. It
fires with a tuple of ``(result, [extra text])``, where ``result`` is
one of the constants from :mod:`buildbot.status.builder`. The extra
text is a list of short strings which should be appended to the Build's
text results. For example, a test step may add ``17 failures`` to the
Build's status by this mechanism.
The deferred will errback if the step encounters an exception,
including an exception on the slave side (or if the slave goes away
altogether). Normal build/test failures will *not* cause an errback.
.. py:method:: start()
:returns: ``None`` or :data:`~buildbot.status.results.SKIPPED`
Begin the step. Subclasses should override this method to do local
processing, fire off remote commands, etc. The parent method raises
:exc:`NotImplementedError`.
Note that this method does *not* return a Deferred. When the step is
done, it should call :meth:`finished`, with a result -- a constant from
:mod:`buildbot.status.results`. The result will be handed off to
the :class:`~buildbot.process.build.Build`.
If the step encounters an exception, it should call :meth:`failed` with
a Failure object. This method automatically fails the whole build with
an exception. A common idiom is to add :meth:`failed` as an errback on
a Deferred::
cmd = LoggedRemoteCommand(args)
d = self.runCommand(cmd)
def suceed(_):
self.finished(results.SUCCESS)
d.addCallback(succeed)
d.addErrback(self.failed)
If the step decides it does not need to be run, :meth:`start` can
return the constant :data:`~buildbot.status.results.SKIPPED`. In this
case, it is not necessary to call :meth:`finished` directly.
.. py:method:: finished(results)
:param results: a constant from :mod:`~buildbot.status.results`
A call to this method indicates that the step is finished and the build
should analyze the results and perhaps proceed to the next step. The
step should not perform any additional processing after calling this
method.
.. py:method:: failed(failure)
:param failure: a :class:`~twisted.python.failure.Failure` instance
Similar to :meth:`finished`, this method indicates that the step is
finished, but handles exceptions with appropriate logging and
diagnostics.
This method handles :exc:`BuildStepFailed` specially, by calling
``finished(FAILURE)``. This provides subclasses with a shortcut to
stop execution of a step by raising this failure in a context where
:meth:`failed` will catch it.
.. py:method:: interrupt(reason)
:param reason: why the build was interrupted
:type reason: string or :class:`~twisted.python.failure.Failure`
This method is used from various control interfaces to stop a running
step. The step should be brought to a halt as quickly as possible, by
cancelling a remote command, killing a local process, etc. The step
must still finish with either :meth:`finished` or :meth:`failed`.
The ``reason`` parameter can be a string or, when a slave is lost
during step processing, a :exc:`~twisted.internet.error.ConnectionLost`
failure.
The parent method handles any pending lock operations, and should be
called by implementations in subclasses.
.. py:attribute:: stopped
If false, then the step is running. If true, the step is not running,
or has been interrupted.
This method provides a convenient way to summarize the status of the step
for status displays:
.. py:method:: describe(done=False)
:param done: If true, the step is finished.
:returns: list of strings
Describe the step succinctly. The return value should be a sequence of
short strings suitable for display in a horizontally constrained space.
.. note::
Be careful not to assume that the step has been started in this
method. In relatively rare circumstances, steps are described
before they have started. Ideally, unit tests should be used to
ensure that this method is resilient.
Build steps support progress metrics - values that increase roughly
linearly during the execution of the step, and can thus be used to
calculate an expected completion time for a running step. A metric may be
a count of lines logged, tests executed, or files compiled. The build
mechanics will take care of translating this progress information into an
ETA for the user.
.. py:method:: setProgress(metric, value)
:param metric: the metric to update
:type metric: string
:param value: the new value for the metric
:type value: integer
Update a progress metric. This should be called by subclasses that can
provide useful progress-tracking information.
The specified metric name must be included in :attr:`progressMetrics`.
The following methods are provided as utilities to subclasses. These
methods should only be invoked after the step is started.
.. py:method:: slaveVersion(command, oldVersion=None)
:param command: command to examine
:type command: string
:param oldVersion: return value if the slave does not specify a version
:returns: string
Fetch the version of the named command, as specified on the slave. In
practice, all commands on a slave have the same version, but passing
``command`` is still useful to ensure that the command is implemented
on the slave. If the command is not implemented on the slave,
:meth:`slaveVersion` will return ``None``.
Versions take the form ``x.y`` where ``x`` and ``y`` are integers, and
are compared as expected for version numbers.
Buildbot versions older than 0.5.0 did not support version queries; in
this case, :meth:`slaveVersion` will return ``oldVersion``. Since such
ancient versions of Buildbot are no longer in use, this functionality
is largely vestigial.
.. py:method:: slaveVersionIsOlderThan(command, minversion)
:param command: command to examine
:type command: string
:param minversion: minimum version
:returns: boolean
This method returns true if ``command`` is not implemented on the
slave, or if it is older than ``minversion``.
.. py:method:: getSlaveName()
:returns: string
Get the name of the buildslave assigned to this step.
.. py:method:: runCommand(command)
:returns: Deferred
This method connects the given command to the step's buildslave and
runs it, returning the Deferred from
:meth:`~buildbot.process.buildstep.RemoteCommand.run`.
.. py:method:: addURL(name, url)
:param name: URL name
:param url: the URL
Add a link to the given ``url``, with the given ``name`` to displays of
this step. This allows a step to provide links to data that is not
available in the log files.
The :class:`BuildStep` class provides minimal support for log handling,
that is extended by the :class:`LoggingBuildStep` class. The following
methods provide some useful behaviors. These methods can be called while
the step is running, but not before.
.. py:method:: addLog(name)
:param name: log name
:returns: :class:`~buildbot.status.logfile.LogFile` instance
Add a new logfile with the given name to the step, and return the log
file instance.
.. py:method:: getLog(name)
:param name: log name
:returns: :class:`~buildbot.status.logfile.LogFile` instance
:raises: :exc:`KeyError` if the log is not found
Get an existing logfile by name.
.. py:method:: addCompleteLog(name, text)
:param name: log name
:param text: content of the logfile
This method adds a new log and sets ``text`` as its content. This is
often useful to add a short logfile describing activities performed on
the master. The logfile is immediately closed, and no further data can
be added.
.. py:method:: addHTMLLog(name, html)
:param name: log name
:param html: content of the logfile
Similar to :meth:`addCompleteLog`, this adds a logfile containing
pre-formatted HTML, allowing more expressiveness than the text format
supported by :meth:`addCompleteLog`.
.. py:method:: addLogObserver(logname, observer)
:param logname: log name
:param observer: log observer instance
Add a log observer for the named log. The named log need not have been
added already: the observer will be connected when the log is added.
See :ref:`Adding-LogObservers` for more information on log observers.
LoggingBuildStep
----------------
.. py:class:: LoggingBuildStep(logfiles, lazylogfiles, log_eval_func, name, locks, haltOnFailure, flunkOnWarnings, flunkOnFailure, warnOnWarnings, warnOnFailure, alwaysRun, progressMetrics, useProgress, doStepIf)
:param logfiles: see :bb:step:`ShellCommand`
:param lazylogfiles: see :bb:step:`ShellCommand`
:param log_eval_func: see :bb:step:`ShellCommand`
The remaining arguments are passed to the :class:`BuildStep` constructor.
This subclass of :class:`BuildStep` is designed to help its subclasses run
remote commands that produce standard I/O logfiles. It:
* tracks progress using the length of the stdout logfile
* provides hooks for summarizing and evaluating the command's result
* supports lazy logfiles
* handles the mechanics of starting, interrupting, and finishing remote
commands
* detects lost slaves and finishes with a status of
:data:`~buildbot.status.results.RETRY`
.. py:attribute:: logfiles
The logfiles to track, as described for :bb:step:`ShellCommand`. The
contents of the class-level ``logfiles`` attribute are combined with
those passed to the constructor, so subclasses may add log files with a
class attribute::
class MyStep(LoggingBuildStep):
logfiles = dict(debug='debug.log')
Note that lazy logfiles cannot be specified using this method; they
must be provided as constructor arguments.
.. py:method:: startCommand(command)
:param command: the :class:`~buildbot.process.buildstep.RemoteCommand`
instance to start
.. note::
This method permits an optional ``errorMessages`` parameter,
allowing errors detected early in the command process to be logged.
It will be removed, and its use is deprecated.
Handle all of the mechanics of running the given command. This sets
up all required logfiles, keeps status text up to date, and calls the
utility hooks described below. When the command is finished, the step
is finished as well, making this class is unsuitable for steps that
run more than one command in sequence.
Subclasses should override
:meth:`~buildbot.process.buildstep.BuildStep.start` and, after setting
up an appropriate command, call this method. ::
def start(self):
cmd = RemoteShellCommand(..)
self.startCommand(cmd, warnings)
To refine the status output, override one or more of the following methods.
The :class:`LoggingBuildStep` implementations are stubs, so there is no
need to call the parent method.
.. py:method:: commandComplete(command)
:param command: the just-completed remote command
This is a general-purpose hook method for subclasses. It will be called
after the remote command has finished, but before any of the other hook
functions are called.
.. py:method:: createSummary(stdio)
:param stdio: stdio :class:`~buildbot.status.logfile.LogFile`
This hook is designed to perform any summarization of the step, based
either on the contents of the stdio logfile, or on instance attributes
set earlier in the step processing. Implementations of this method
often call e.g., :meth:`~BuildStep.addURL`.
.. py:method:: evaluateCommand(command)
:param command: the just-completed remote command
:returns: step result from :mod:`buildbot.status.results`
This hook should decide what result the step should have. The default
implementation invokes ``log_eval_func`` if it exists, and looks at
:attr:`~buildbot.process.buildstep.RemoteCommand.rc` to distinguish
:data:`~buildbot.status.results.SUCCESS` from
:data:`~buildbot.status.results.FAILURE`.
The remaining methods provide an embarassment of ways to set the summary of
the step that appears in the various status interfaces. The easiest way to
affect this output is to override :meth:`~BuildStep.describe`. If that is
not flexible enough, override :meth:`getText` and/or :meth:`getText2`.
.. py:method:: getText(command, results)
:param command: the just-completed remote command
:param results: step result from :meth:`evaluateCommand`
:returns: a list of short strings
This method is the primary means of describing the step. The default
implementation calls :meth:`~BuildStep.describe`, which is usally the
easiest method to override, and then appends a string describing the
step status if it was not successful.
.. py:method:: getText2(command, results)
:param command: the just-completed remote command
:param results: step result from :meth:`evaluateCommand`
:returns: a list of short strings
Like :meth:`getText`, this method summarizes the step's result, but it
is only called when that result affects the build, either by making it
halt, flunk, or end with warnings.
Exceptions
----------
.. py:exception:: BuildStepFailed
This exception indicates that the buildstep has failed. It is useful as a
way to skip all subsequent processing when a step goes wrong. It is
handled by :meth:`BuildStep.failed`.
