Django Celery Periodic Task not running (Heroku)?

Question

I have a Django application that I've deployed with Heroku. I'm trying to user celery to create a periodic task every minute. However, when I observe the logs for the worker using the following command:

heroku logs -t -p worker 

I don't see my task being executed. Perhaps there is a step I'm missing? This is my configuration below...

Procfile

web: gunicorn activiist.wsgi --log-file -
worker: celery worker --app=trending.tasks.app

Tasks.py

import celery
app = celery.Celery('activiist')
import os
from celery.schedules import crontab
from celery.task import periodic_task
from django.conf import settings
app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)

app.conf.update(BROKER_URL=os.environ['REDIS_URL'],
                CELERY_RESULT_BACKEND=os.environ['REDIS_URL'])
os.environ['DJANGO_SETTINGS_MODULE'] = 'activiist.settings'
from trending.views import *
@periodic_task(run_every=crontab())
def add():
    getarticles(30)

One thing to add. When I run the task using the python shell and the "delay()" command, the task does indeed run (it shows in the logs) -- but it only runs once and only when executed.

Answer 1

You need separate worker for the beat process (which is responsible for executing periodic tasks):

web: gunicorn activiist.wsgi --log-file -
worker: celery worker --app=trending.tasks.app
beat: celery --app=trending.tasks.app

Worker isn't necessary for periodic tasks so the relevant line can be omitted. The other possibility is to embed beat inside the worker:

web: gunicorn activiist.wsgi --log-file -
worker: celery worker --app=trending.tasks.app -B

but to quote the celery documentation :

You can also start embed beat inside the worker by enabling workers -B option, this is convenient if you will never run more than one worker node, but it's not commonly used and for that reason is not recommended for production use