Job scheduler in python

I want a job scheduler in python something like Quartz-Scheduler for java.

Options

1. sched – Generic event scheduler
2. Advanced Python Scheduler
3. Celery: Distributed Task Queue - Periodic tasks
4. dbader/schedule
5. There are many crontab wrapper which I haven’t included.

References:

1. How do I get a Cron like scheduler in Python?
2. Schedule – Python job scheduling for humans

Comparison:

1. Consider switching from APScheduler to celery
2. APScheduler 3.0 released
3. Celery - schedule periodic tasks starting at a specific time

APS

I choose PS finally as it is more powerful and celery requires setup time and is is not meant for task scheduling primarily.

1. APScheduler Job not running after restart

2. My chat on IRC understanding the differences between Quartz and APS:

   ``` knoxxs Hey guys can someone help me with http://stackoverflow.com/questions/35707630/apscheduler-job-not-running-after-restart

   agronholm knoxxs: have you read the docs?

   knoxxs Ya, I read them today only. Am I missing something basic? :/

   agronholm yeah, the description of how misfire grace time works

   knoxxs let me check

   knoxxs thanks

   agronholm if this was a recurring job it’d simply calculate its next run time

   knoxxs Ya after defining misfire_grace_time it worked. Actuallly, when I debugged the code, I saw it submitting the job to the threadpool.

   knoxxs One more thing, the benefit of storing the sate in persistent store is only beneficial in case of error. Am I right?

   knoxxs I am coming from Java background and used Quartz scheduler. It didn’t had any such functionality. So I am having a hard time in digesting it.

   knoxxs @agronholm

   agronholm knoxxs: storing the state is beneficial if you need a job to persist over restarts

   agronholm in my case I needed persistence so that if the app was down when it needed to generate reports, it wouldn’t know to do that otherwise after restart

   agronholm or worse, it would do it again and overwrite the reports

   agronholm for that I’d have to set a misfire grace time of several hours at least

   knoxxs ok

   knoxxs one more thing…after reading the docs, I understood that in APS we need the register the job after creating the scheduler instance.

   knoxxs Because of this the if someone has to write a new job they have to register it manually. Is there any way to automate this.

   knoxxs IMHO Quartz, the java scheduler, used to store the registry in db

   knoxxs I think I can do the same with APS too.

   knoxxs Am i thinking in right direction? Also why no one else needed it before?

   agronholm knoxxs: what registry are you talking about?

   agronholm if you add a job to the job store, it will stay there if the job store is persistent

   knoxxs Initially I have to add the job to scheduler instance.

   agronholm yes, as you would in quartz too

   knoxxs Ohhh I got it … In quartz I used to extend a class. That must be informing quartz

   knoxxs base job class of quartz

   knoxxs thanks… Yeah The standard base class was doing everything. I checked it.

   knoxxs Thanks for all the help. :) ``` Extra resources:

3. Scheduled Jobs with Custom Clock Processes in Python with APScheduler
4. apscheduler in Flask executes twice
5. How to run recurring task in the Python Flask framework?