RemoteCommands
==============

.. py:currentmodule:: buildbot.process.buildstep

Most of the action in build steps consists of performing operations on the
slave.  This is accomplished via :class:`RemoteCommand` and its subclasses.
Each represents a single operation on the slave.

Most data is returned to a command via updates.  These updates are described in
detail in :ref:`master-slave-updates`.

RemoteCommand
~~~~~~~~~~~~~

.. py:class:: RemoteCommand(remote_command, args, collectStdout=False, ignore_updates=False, decodeRC=dict(0))

    :param remote_command: command to run on the slave
    :type remote_command: string
    :param args: arguments to pass to the command
    :type args: dictionary
    :param collectStdout: if True, collect the command's stdout
    :param ignore_updates: true to ignore remote updates
    :param decodeRC: dictionary associating ``rc`` values to buildsteps results constants
    	   	     (e.g. ``SUCCESS``, ``FAILURE``, ``WARNINGS``)

    This class handles running commands, consisting of a command name and
    a dictionary of arguments.  If true, ``ignore_updates`` will suppress any
    updates sent from the slave.

    This class handles updates for ``stdout``, ``stderr``, and ``header`` by
    appending them to a ``stdio`` logfile, if one is in use.  It handles
    updates for ``rc`` by recording the value in its ``rc`` attribute.

    Most slave-side commands, even those which do not spawn a new process on
    the slave, generate logs and an ``rc``, requiring this class or one of its
    subclasses.  See :ref:`master-slave-updates` for the updates that each
    command may send.

    .. py:attribute:: active

        True if the command is currently running

    .. py:method:: run(step, remote)

        :param step: the buildstep invoking this command
        :param remote: a reference to the remote :class:`SlaveBuilder`
            instance
        :returns: Deferred

        Run the command.  Call this method to initiate the command; the
        returned Deferred will fire when the command is complete.  The Deferred
        fires with the :class:`RemoteCommand` instance as its value.

    .. py:method:: interrupt(why)

        :param why: reason for interrupt
        :type why: Twisted Failure
        :returns: Deferred

        This method attempts to stop the running command early.  The Deferred
        it returns will fire when the interrupt request is received by the
        slave; this may be a long time before the command itself completes, at
        which time the Deferred returned from :meth:`run` will fire.

    .. py:method:: results()

        :returns: results constant

        This method checks the ``rc`` against the decodeRC dictionary, and returns results constant

    .. py:method:: didFail()

        :returns: bool

        This method returns True if the results() function returns FAILURE

    The following methods are invoked from the slave.  They should not be
    called directly.

    .. py:method:: remote_update(updates)

        :param updates: new information from the slave

        Handles updates from the slave on the running command.  See
        :ref:`master-slave-updates` for the content of the updates.  This class
        splits the updates out, and handles the ``ignore_updates`` option, then
        calls :meth:`remoteUpdate` to process the update.

    .. py:method:: remote_complete(failure=None)

        :param failure: the failure that caused the step to complete, or None
            for success

        Called by the slave to indicate that the command is complete.  Normal
        completion (even with a nonzero ``rc``) will finish with no failure; if
        ``failure`` is set, then the step should finish with status
        :attr:`~buildbot.status.results.EXCEPTION`.

    These methods are hooks for subclasses to add functionality.

    .. py:method:: remoteUpdate(update)

        :param update: the update to handle

        Handle a single update.  Subclasses must override this method.

    .. py:method:: remoteComplete(failure)

        :param failure: the failure that caused the step to complete, or None
            for success
        :returns: Deferred

        Handle command completion, performing any necessary cleanup.
        Subclasses should override this method.  If ``failure`` is not None, it
        should be returned to ensure proper processing.

    .. py:attribute:: logs

        A dictionary of :class:`~buildbot.status.logfile.LogFile` instances
        representing active logs.  Do not modify this directly -- use
        :meth:`useLog` instead.

    .. py:attribute:: rc

        Set to the return code of the command, after the command has completed.
        For compatibility with shell commands, 0 is taken to indicate success,
        while nonzero return codes indicate failure.

    .. py:attribute:: stdout

        If the ``collectStdout`` constructor argument is true, then this
        attribute will contain all data from stdout, as a single string.  This
        is helpful when running informational commands (e.g., ``svnversion``),
        but is not appropriate for commands that will produce a large amount of
        output, as that output is held in memory.

    To set up logging, use :meth:`useLog` or :meth:`useLogDelayed` before
    starting the command:

    .. py:method:: useLog(log, closeWhenFinished=False, logfileName=None)

        :param log: the :class:`~buildbot.status.logfile.LogFile` instance to add to.
        :param closeWhenFinished: if true, call
            :meth:`~buildbot.status.logfile.LogFile.finish` when the command is
            finished.
        :param logfileName: the name of the logfile, as given to the slave.
            This is ``stdio`` for standard streams.

        Route log-related updates to the given logfile.  Note that ``stdio`` is
        not included by default, and must be added explicitly.  The
        ``logfileName`` must match the name given by the slave in any ``log``
        updates.

    .. py:method:: useLogDelayed(log, logfileName, activateCallback, closeWhenFinished=False)

        :param log: the :class:`~buildbot.status.logfile.LogFile` instance to add to.
        :param logfileName: the name of the logfile, as given to the slave.
            This is ``stdio`` for standard streams.
        :param activateCallback: callback for when the log is added; see below
        :param closeWhenFinished: if true, call
            :meth:`~buildbot.status.logfile.LogFile.finish` when the command is
            finished.

        Similar to :meth:`useLog`, but the logfile is only actually added when
        an update arrives for it.  The callback, ``activateCallback``, will be
        called with the :class:`~buildbot.process.buildstep.RemoteCommand`
        instance when the first update for the log is delivered.

    With that finished, run the command using the inherited
    :meth:`~buildbot.process.buildstep.RemoteCommand.run` method.  During the
    run, you can inject data into the logfiles with any of these methods:

    .. py:method:: addStdout(data)

        :param data: data to add to the logfile

    Add stdout data to the ``stdio`` log.

    .. py:method:: addStderr(data)

        :param data: data to add to the logfile

    Add stderr data to the ``stdio`` log.

    .. py:method:: addHeader(data)

        :param data: data to add to the logfile

    Add header data to the ``stdio`` log.

    .. py:method:: addToLog(logname, data)

        :param logname: the logfile to receive the data
        :param data: data to add to the logfile

    Add data to a logfile other than ``stdio``.

.. py:class:: RemoteShellCommand(workdir, command, env=None, want_stdout=True, want_stderr=True, timeout=20*60, maxTime=None, logfiles={}, usePTY="slave-config", logEnviron=True, collectStdio=False)

    :param workdir: directory in which command should be executed, relative to
        the builder's basedir.
    :param command: shell command to run
    :type command: string or list
    :param want_stdout: If false, then no updates will be sent for stdout.
    :param want_stderr: If false, then no updates will be sent for stderr.
    :param timeout: Maximum time without output before the command is killed.
    :param maxTime: Maximum overall time from the start before the command is
        killed.
    :param env: A dictionary of environment variables to augment or replace the
        existing environment on the slave.
    :param logfiles: Additional logfiles to request from the slave.
    :param usePTY: True to use a PTY, false to not use a PTY; the default value
        uses the default configured on the slave.
    :param logEnviron: If false, do not log the environment on the slave.
    :param collectStdout: If True, collect the command's stdout.

    Most of the constructor arguments are sent directly to the slave; see
    :ref:`shell-command-args` for the details of the formats.  The
    ``collectStdout`` parameter is as described for the parent class.

    This class is used by the :bb:step:`ShellCommand` step, and by steps that
    run multiple customized shell commands.
