Mailman runner controlΒΆ

Mailman has a number of runner subprocesses which perform long-running tasks such as listening on an LMTP port, processing REST API requests, or processing messages in a queue directory. In normal operation, the mailman command is used to start, stop and manage the runners. This is just a wrapper around the real master watcher, which handles runner starting, stopping, exiting, and log file reopening.

>>> from mailman.testing.helpers import TestableMaster

Start the master in a sub-thread.

>>> master = TestableMaster()
>>> master.start()

There should be a process id for every runner that claims to be startable.

>>> from lazr.config import as_boolean
>>> startable_runners = [conf for conf in config.runner_configs
...                      if as_boolean(conf.start)]
>>> len(list(master.runner_pids)) == len(startable_runners)

Now verify that all the runners are running.

>>> import os

# This should produce no output.
>>> for pid in master.runner_pids:
...     os.kill(pid, 0)

Stop the master process, which should also kill (and not restart) the child runner processes.

>>> master.stop()

None of the children are running now.

>>> import errno
>>> from contextlib import suppress
>>> for pid in master.runner_pids:
...     with suppress(ProcessLookupError):
...         os.kill(pid, 0)
...         print('Process did not exit:', pid)