# The Task runner

Mailman has a Task runner that executes periodic tasks.

## Configuration

By default, the Task runner executes tasks once per hour to evict expired pending requests and cache entries and to delete any saved workflow states and saved message store messages orphaned by deleting the associated pending request. This timing is configurable in the `[mailman]` section of the configuration.:

    # mailman.cfg
    [mailman]
    run_tasks_every: 1d

This will run the tasks once per day instead of once per hour.

## Logging

The Task runner writes some simple log messages to a new task log.

    >>> import doctest
    >>> doctest.ELLIPSIS_MARKER = 'xxx'
    >>> from mailman.testing import helpers
    >>> from mailman.config import config
    >>> from mailman.runners.task import TaskRunner
    >>> mark = helpers.LogFileMark('mailman.task')
    >>> runner = helpers.make_testable_runner(TaskRunner)
    >>> runner.run()
    >>> print(mark.read())
    xxx Task runner evicted 0 expired pendings
    xxx Task runner deleted 0 orphaned workflows
    xxx Task runner deleted 0 orphaned requests
    xxx Task runner deleted 0 orphaned messages
    xxx Task runner evicted expired cache entries

    >>> doctest.ELLIPSIS_MARKER = '...'