Examples of Django and Celery: Periodic Tasks

Question

I have been fighting the Django/Celery documentation for a while now and need some help.

I would like to be able to run Periodic Tasks using django-celery. I have seen around the internet (and the documentation) several different formats and schemas for how one should go about achieving this using Celery...

Can someone help with a basic, functioning example of the creation, registration and execution of a django-celery periodic task? In particular, I want to know whether I should write a task that extends the PeriodicTask class and register that, or whether I should use the @periodic_task decorator, or whether I should use the @task decorator and then set up a schedule for the task's execution.

I don't mind if all three ways are possible, but I would like to see an example of at least one way that works. Really appreciate your help.

Answer 1

What's wrong with the example from the docs?

from celery.task import PeriodicTask
from clickmuncher.messaging import process_clicks
from datetime import timedelta


class ProcessClicksTask(PeriodicTask):
    run_every = timedelta(minutes=30)

    def run(self, **kwargs):
        process_clicks()

You could write the same task using a decorator:

from celery.task.schedules import crontab
from celery.task import periodic_task

@periodic_task(run_every=crontab(minute="*/30"))
def process_clicks():
    ....

The decorator syntax simply allows you to turn an existing function/task into a periodic task without modifying them directly.

For the tasks to be executed celerybeat must be running.