Comment 5 for bug 939087

Reviewed: https://review.openstack.org/18618
Committed: http://github.com/openstack/nova/commit/9fb647ec100133b1ee5903535507c74d408f4790
Submitter: Jenkins
Branch: master

commit 9fb647ec100133b1ee5903535507c74d408f4790
Author: Michael Still <email address hidden>
Date: Mon Dec 24 15:00:52 2012 +1100

    Refactor periodic tasks.

    This review allows periodic tasks to be enabled or disabled in the
    decorator, as well as by specifying an interval which is negative.

    The spacing between runs of a periodic task is now specified in
    seconds, with zero meaning the default spacing which is currently 60
    seconds.

    There is also a new argument to the decorator which indicates if a
    periodic task _needs_ to be run in the nova-compute process. There is
    also a flag (run_external_periodic_tasks) which can be used to move
    these periodic tasks out of the nova-compute process.

    I also remove the periodic_interval flag to services, as the interval
    between runs is now dynamic based on the number of seconds that a
    periodic task wants to wait for its next run. For callers who want to
    twiddle the sleep period (for example unit tests), there is a
    create() argument periodic_interval_max which lets the period
    periodic_tasks() specifies be overridden. This is not exposed as a
    flag because I cannot see a use case for that. It is needed for unit
    testing however.

    DocImpact. Resolves bug 939087.

    Change-Id: I7f245a88b8d229a481c1b65a4c0f1e2769bf3901