Set up a scheduled job?

I've been working on a web app using Django, and I'm curious if there is a way to schedule a job to run periodically.

Basically I just want to run through the database and make some calculations/updates on an automatic, regular basis, but I can't seem to find any documentation on doing this.

Does anyone know how to set this up?

To clarify: I know I can set up a cron job to do this, but I'm curious if there is some feature in Django that provides this functionality. I'd like people to be able to deploy this app themselves without having to do much config (preferably zero).

I've considered triggering these actions "retroactively" by simply checking if a job should have been run since the last time a request was sent to the site, but I'm hoping for something a bit cleaner.

Solution 1:

One solution that I have employed is to do this:

1) Create a custom management command, e.g.

python manage.py my_cool_command

2) Use cron (on Linux) or at (on Windows) to run my command at the required times.

This is a simple solution that doesn't require installing a heavy AMQP stack. However there are nice advantages to using something like Celery, mentioned in the other answers. In particular, with Celery it is nice to not have to spread your application logic out into crontab files. However the cron solution works quite nicely for a small to medium sized application and where you don't want a lot of external dependencies.

EDIT:

In later version of windows the at command is deprecated for Windows 8, Server 2012 and above. You can use schtasks.exe for same use.

**** UPDATE **** This the new link of django doc for writing the custom management command

Solution 2:

Celery is a distributed task queue, built on AMQP (RabbitMQ). It also handles periodic tasks in a cron-like fashion (see periodic tasks). Depending on your app, it might be worth a gander.

Celery is pretty easy to set up with django (docs), and periodic tasks will actually skip missed tasks in case of a downtime. Celery also has built-in retry mechanisms, in case a task fails.