It's not a question but help to those who will find that the declaration of periodic tasks described in celery 4.0.1 documentation is hard to integrate in django: http://docs.celeryproject.org/en/latest/userguide/periodic-tasks.html#entries
copy paste celery config file main_app/celery.py:
from celery import Celery
from celery.schedules import crontab
app = Celery()
@app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
# Calls test('hello') every 10 seconds.
sender.add_periodic_task(10.0, test.s('hello'), name='add every 10')
# Calls test('world') every 30 seconds
sender.add_periodic_task(30.0, test.s('world'), expires=10)
# Executes every Monday morning at 7:30 a.m.
sender.add_periodic_task(
crontab(hour=7, minute=30, day_of_week=1),
test.s('Happy Mondays!'),
)
@app.task
def test(arg):
print(arg)
Question:
But what if we use django and our tasks are placed in another app? With celery 4.0.1 we no longer have @periodic_task decorator. So let's see what we can do.
First case:
If you prefer to keep tasks and their schedule close to each other:
main_app/some_app/tasks.py:
from main_app.celery import app as celery_app
@celery_app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
# Calls test('hello') every 10 seconds.
sender.add_periodic_task(10.0, test.s('hello'))
@celery_app.task
def test(arg):
print(arg)
We can run beat in debug mode:
celery -A main_app beat -l debug
And we will see that there's no such periodic task.
Second case:
We can try to describe all periodic tasks in config file like this:
main_app/celery.py:
...
app = Celery()
@app.on_after_configure.connect
def setup_periodic_tasks(sender, **kwargs):
# Calls test('hello') every 10 seconds.
from main_app.some_app.tasks import test
sender.add_periodic_task(10.0, test.s('hello'))
...
The result is the same. But it will behave differently that you can see with manual debugging via pdb. In first example setup_periodic_tasks callback will not be fired at all. But in second example we'll get django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet. (This exception will not be print out)