RQ Retry Scheduler
RQ Retry Scheduler extends the RQ worker class to provide functionality to enqueue jobs based on time.
Additionally, it provides a worker that will automatically retry failed jobs using a backoff scheme.
Usage
Queues
The rq_retry_scheduler.Queue
class can be used as a drop in replacement for rq.Queue
. It provides two additional enqueuing methods:
-
enqueue_at
- Enqueue the job at the specified time. The time should be adatetime.datetime
object with the UTC timezone. -
enqueue_in
- Enqueue the job after the specified amount of time. The time should be adatetime.timedelta
object.
Additionally, two other methods are available enqueue_job_at
and enqueue_job_in
which work like the above methods but take a rq.Job
object as the paramter.
Getting list of jobs
Queue.scheduled_jobs
is a generator that produces the jobs that are currently scheduled for a particular queue.
Scheduler.schedule
returns a list of job ids and scheduled time.
Checking if a job is scheduled
You can check if a job or job id is currently scheduled. Example: job in queue
Unscheduling jobs
You can unschedule jobs with Queue.remove_job
. This removes the job from the scheduler queue but does not remove it from RQ.
Repeating jobs
Once a job has been enqueued you can set it to repeat with Queue.repeat
which takes the job and a datetime.timedelta
object. Additionally you can
pass a max_runs
value to limit the number of times it will repeat.
If the job is not already in the queue it will be enqueued at the given interval.
In order to ensure that job results cleanup doesn't remove the job (thus breaking the repetition) the job is copied into a new job.
The parent job can be accessed via Job.parent
for the repeated jobs.
Due to how the jobs are put into the work queues the maximum frequency is controlled by the scheduler's interval.
Scheduler
In order to move jobs from the schedule queue into the proper RQ queue a scheduler needs to be ran.
This can be accomplished via the rqscheduler
script. Additionally, you can extend from rq_retry_scheduler.Scheduler
to customize the functonality.
Worker
A worker is provided that will requeue jobs that fail using a defiend backoff strategy.
The worker is designed to use the functionality from the Queue
class to control the backoff.
The worker can be used by using the -w
option to rq worker
: rq worker -w 'rq_rety_scheduler.Worker
.
The backoff times and total attempts is controlled by Worker.retry_delays
.
Installation
Install via pip
pip install rq-retry-scheduler
Acknowledgements
This package was based heavily on the work of RQ Scheduler.