Django ImproperlyConfigured - The SECRET_KEY setting must not be empty

Question

I am running a django application using celery. I am getting a strange error in my tasks.py file, which is as follows:

from __future__ import absolute_import

from celery import shared_task
from django.contrib.auth.models import User

# some code 
# ....

Here is the error:

django.core.exceptions.ImproperlyConfigured: The SECRET_KEY must not be empty.

In my settings.py, SECRET_KEY is defined

# ...
import myproj.tasks
import djcelery

djcelery.setup_loader()

# ...
SECRET_KEY = '18730s9n9sjxamsuJSismxOIAmso102xjAs'
# ...

The application runs fine if I comment the import in the tasks.py file:

# from django.contrib.auth.models import User

and, more surprisingly, it also runs fine if I make the exact same imports in another file (e.g. testfile.py) in the same directory.

Why is this error happening?

Edit: Here is my celery.py file

from __future__ import absolute_import
import os
from celery import Celery

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myproj.settings')

from django.conf import settings #noqa

app = Celery('myproj')

app.config_from_object('django.conf:settings')
app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)

Answer 1

The issue was caused by importing the celery tasks into the settings file in order to pass them to the CELERYBEAT_SCHEDULE setting.

This import caused a circular import because when the task is imported it will load the settings which only loaded up until the point where the task was imported, thus complaining that no SECRET_KEY was configured.

To solve this (and as general best practice), when configuring CELERYBEAT_SCHEDULE use the path to the task like so:

CELERYBEAT_SCHEDULE = {
    'add-every-30-seconds': {
        'task': 'myapp.tasks.my_task',
        'schedule': timedelta(seconds=30),
        'args': (16, 16)
    },
}

Source http://docs.celeryproject.org/en/latest/userguide/periodic-tasks.html#entries