luigi.contrib.external_program module

Template tasks for running external programs as luigi tasks.

This module is primarily intended for when you need to call a single external program or shell script, and it’s enough to specify program arguments and environment variables.

If you need to run multiple commands, chain them together or pipe output from one command to the next, you’re probably better off using something like plumbum, and wrapping plumbum commands in normal luigi Task s.

class luigi.contrib.external_program.ExternalProgramTask(*args, **kwargs)

Bases: Task

Template task for running an external program in a subprocess

The program is run using subprocess.Popen, with args passed as a list, generated by program_args() (where the first element should be the executable). See subprocess.Popen for details.

Your must override program_args() to specify the arguments you want, and you can optionally override program_environment() if you want to control the environment variables (see ExternalPythonProgramTask for an example).

By default, the output (stdout and stderr) of the run external program is being captured and displayed after the execution has ended. This behaviour can be overridden by passing --capture-output False

capture_output = Insignificant BoolParameter (defaults to True)

stream_for_searching_tracking_url = Insignificant ChoiceParameter (defaults to none): Stream for searching tracking URL Choices: {stderr, none, stdout}

Used for defining which stream should be tracked for URL, may be set to ‘stdout’, ‘stderr’ or ‘none’.

Default value is ‘none’, so URL tracking is not performed.

tracking_url_pattern = Insignificant OptionalParameter (defaults to None): Regex pattern used for searching URL in the logs of the external program

Regex pattern used for searching URL in the logs of the external program.

If a log line matches the regex, the first group in the matching is set as the tracking URL for the job in the web UI. Example: ‘Job UI is here: (https?://.*)’.

Default value is None, so URL tracking is not performed.

program_args()

Override this method to map your task parameters to the program arguments

Returns:

list to pass as args to subprocess.Popen

program_environment()

Override this method to control environment variables for the program

Returns:

dict mapping environment variable names to values

property always_log_stderr

When True, stderr will be logged even if program execution succeeded

Override to False to log stderr only when program execution fails.

build_tracking_url(logs_output)

This method is intended for transforming pattern match in logs to an URL :param logs_output: Found match of self.tracking_url_pattern :return: a tracking URL for the task

run()

The task run method, to be overridden in a subclass.

See Task.run

class luigi.contrib.external_program.ExternalProgramRunContext(proc)

Bases: object

kill_job(captured_signal=None, stack_frame=None)

exception luigi.contrib.external_program.ExternalProgramRunError(message, args, env=None, stdout=None, stderr=None)

Bases: RuntimeError

class luigi.contrib.external_program.ExternalPythonProgramTask(*args, **kwargs)

Bases: ExternalProgramTask

Template task for running an external Python program in a subprocess

Simple extension of ExternalProgramTask, adding two luigi.parameter.Parameter s for setting a virtualenv and for extending the PYTHONPATH.

virtualenv = OptionalParameter (defaults to None): path to the virtualenv directory to use. It should point to the directory containing the ``bin/activate`` file used for enabling the virtualenv.

extra_pythonpath = OptionalParameter (defaults to None): extend the search path for modules by prepending this value to the ``PYTHONPATH`` environment variable.

program_environment()

Override this method to control environment variables for the program

Returns:

dict mapping environment variable names to values