Changelog:
===========
Add is_locked(lock_name) to test whether lock is held.
Allow raising CancelExecution within a Task, and override retries.
Add a very basic redis-backed lock that can be acquired more than once (to provide a rudimentary semaphore).
Add a periodic_task() wrapper for MiniHuey class.
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
(cherry picked from commit e7c7c60edd)
Signed-off-by: Armin Kuster <akuster808@gmail.com>
