service thread group graceful is not working

[TommyLike]

Graceful exit is not working since we removed the timers before waiting them to complete, see here [1]

[1]: https://github.com/openstack/oslo.service/blob/ccbc263e2ec9028edd532367f1c19ebdb2be0ce6/oslo_service/threadgroup.py#L131

[Zane Bitter (zaneb)]

Specifically, periodic timers spawned a thread each time the timer is triggered. Calling stop(graceful=True) does not wait for those tasks that may be running to complete before returning. Only tasks created by add_thread(), not add_timer(), are guaranteed to be complete.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/558418
Committed: https://git.openstack.org/cgit/openstack/oslo.service/commit/?id=20a217817141891615b854936d8d721f2e0973b2
Submitter: Zuul
Branch: master

commit 20a217817141891615b854936d8d721f2e0973b2
Author: TommyLike <email address hidden>
Date: Tue Apr 3 15:39:31 2018 +0800

    [ThreadGroup] Don't remove timer when stop timers

    Graceful exit is not working since we removed the timers
    before waiting them to complete.

    Closes-Bug: #1769825
    Change-Id: I2e52b680a09d337d9b598a4826132df8c7b0b4d9

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/oslo.service 1.31.2 release.