Django Celery scheduled task django.core.exceptions.ImproperlyConfigured

Question

I am trying to run my scheduled task with the following command:

celery -A Htweetprod2 beat

According to Celery 4.0 documentation to start the scheduled task this command should work, yet I am getting this error:

C:\Users\hisg316\Desktop\Htweetprod2>celery -A Htweetprod2 beat
Traceback (most recent call last):
   File "c:\python27\lib\runpy.py", line 174, in _run_module_as_main
"__main__", fname, loader, pkg_name)
   File "c:\python27\lib\runpy.py", line 72, in _run_code
exec code in run_globals
  File "C:\Python27\Scripts\celery.exe\__main__.py", line 9, in <module>
  File "c:\python27\lib\site-packages\celery\__main__.py", line 14, in main
_main()
  File "c:\python27\lib\site-packages\celery\bin\celery.py", line 326, in main
cmd.execute_from_commandline(argv)
  File "c:\python27\lib\site-packages\celery\bin\celery.py", line 488, in execute_from_commandline
super(CeleryCommand, self).execute_from_commandline(argv)))
  File "c:\python27\lib\site-packages\celery\bin\base.py", line 281, in execute_from_commandline
return self.handle_argv(self.prog_name, argv[1:])
  File "c:\python27\lib\site-packages\celery\bin\celery.py", line 480, in handle_argv
return self.execute(command, argv)
  File "c:\python27\lib\site-packages\celery\bin\celery.py", line 412, in execute
).run_from_argv(self.prog_name, argv[1:], command=argv[0])
  File "c:\python27\lib\site-packages\celery\bin\base.py", line 285, in run_from_argv
sys.argv if argv is None else argv, command)
  File "c:\python27\lib\site-packages\celery\bin\base.py", line 367, in handle_argv
*self.parse_options(prog_name, argv, command))
  File "c:\python27\lib\site-packages\celery\bin\base.py", line 403, in parse_options
self.parser = self.create_parser(prog_name, command)
  File "c:\python27\lib\site-packages\celery\bin\base.py", line 419, in create_parser
self.add_arguments(parser)
  File "c:\python27\lib\site-packages\celery\bin\beat.py", line 114, in add_arguments
'-s', '--schedule', default=c.beat_schedule_filename)
  File "c:\python27\lib\site-packages\celery\utils\collections.py", line 130, in __getattr__
return self[k]
  File "c:\python27\lib\site-packages\celery\utils\collections.py", line 431, in __getitem__
return getitem(k)
  File "c:\python27\lib\site-packages\celery\utils\collections.py", line 280, in __getitem__
return mapping[_key]
  File "c:\python27\lib\UserDict.py", line 36, in __getitem__
if key in self.data:
  File "c:\python27\lib\site-packages\kombu\utils\objects.py", line 44, in __get__
value = obj.__dict__[self.__name__] = self.__get(obj)
  File "c:\python27\lib\site-packages\celery\app\base.py", line 148, in data
return self.callback()
  File "c:\python27\lib\site-packages\celery\app\base.py", line 910, in _finalize_pending_conf
conf = self._conf = self._load_config()
  File "c:\python27\lib\site-packages\celery\app\base.py", line 920, in _load_config
self.loader.config_from_object(self._config_source)
  File "c:\python27\lib\site-packages\celery\loaders\base.py", line 133, in config_from_object
self._conf = force_mapping(obj)
  File "c:\python27\lib\site-packages\celery\utils\collections.py", line 52, in force_mapping
return DictAttribute(m) if not isinstance(m, Mapping) else m
  File "c:\python27\lib\abc.py", line 131, in __instancecheck__
subclass = getattr(instance, '__class__', None)
  File "c:\python27\lib\site-packages\django\utils\functional.py", line 234, in inner
self._setup()
  File "c:\python27\lib\site-packages\django\conf\__init__.py", line 39, in _setup
% (desc, ENVIRONMENT_VARIABLE))
django.core.exceptions.ImproperlyConfigured: Requested settings, but settings are not configured. You must either define the environment variable 
DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

I have carefully followed the instructions in the documentation and settings are configured to the correct app. Am I missing something?

Here is my tasks.py

from celery import Celery
from Htweets2.models import Htweets2
from celery.schedules import crontab

app = Celery('Htweetprod2')

@app.task
def delete_tweets():
    oldtweets = Htweets2.objects.all()
    oldtweets.delete()

CELERYBEAT_SCHEDULE = {
    "delete_tweeets_eachday": {
        'task': "tasks.delete_tweets",
        # Every 1 hour
        'schedule': crontab(hour=1, minute=0),
        'args': (16, 16),
    },
}

Answer 1

The best practice when using Django with Celery is to have your Celery app configured by Django's settings file.

http://docs.celeryproject.org/en/latest/django/first-steps-with-django.html

from __future__ import absolute_import, unicode_literals
import os
from celery import Celery

# set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'proj.settings')

app = Celery('proj')

# Using a string here means the worker don't have to serialize
# the configuration object to child processes.
# - namespace='CELERY' means all celery-related configuration keys
#   should have a `CELERY_` prefix.
app.config_from_object('django.conf:settings', namespace='CELERY')

# Load task modules from all registered Django app configs.
app.autodiscover_tasks()

This uses app.config_from_object() and also sets up your project to automatically discover tasks from tasks.py files in your Django installed apps.

Answer 2

The error message clearly states:

django.core.exceptions.ImproperlyConfigured: Requested settings, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

This means that you either have to define a environment variable called DJANGO_SETTINGS_MODULE or call the method settings.configure in your code before you access the settings.

I would suggest to set the environment variable DJANGO_SETTINGS_MODULE.

Documentation: https://docs.djangoproject.com/en/1.11/topics/settings/#designating-the-settings