django-celery: No result backend configured - django

Question

I am trying to use django-celery in my project
In settings.py I have
CELERY_RESULT_BACKEND = "amqp"
The server started fine with
python manage.py celeryd --setting=settings
But if I want to access a result from a delayed task, I get the following error:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\site-packages\celery\result.py", line 108, in ready
return self.status in self.backend.READY_STATES
File "C:\Python27\lib\site-packages\celery\result.py", line 196, in status
return self.state
File "C:\Python27\lib\site-packages\celery\result.py", line 191, in state
return self.backend.get_status(self.task_id)
File "C:\Python27\lib\site-packages\celery\backends\base.py", line 404, in _is
_disabled
raise NotImplementedError("No result backend configured. "
NotImplementedError: No result backend configured. Please see the documentation
for more information.
It is very strange because when I just run celeryd (with the same celery settings), it works just fine. Has anyone encountered this problem before?
Thanks in advance!

Answer 1

I had the same problem while getting the result back from the celery task although the celery task was executed ( console logs). What i found was, i had the same setting CELERY_RESULT_BACKEND = "redis" in django settings.py but i had also instantiated celery in the tasks.py
celery = Celery('tasks', broker='redis://localhost') - which i suppose overrides the settings.py property and hence it was not configuring the backend server for my celery instance which is used to store the results.
i removed this and let django get celery get properties from settings.py and the sample code worked for me.

Answer 2

If you're just running the samples from http://www.celeryproject.org/tutorials/first-steps-with-celery/, you need to run the console via manage.py:
% python manage.py shell

Answer 3

For those who are in a desperate search for a solution like I was.
Put this line at the end of the settings.py script:
djcelery.setup_loader()
Looks like django-celery is not going to consider it's own settings without a strict order.

Answer 4

In my case, the problem was that I was passing the CELERY_RESULT_BACKEND argument to the celery constructor:
Celery('proj',
broker = 'amqp://guest:guest#localhost:5672//',
CELERY_RESULT_BACKEND='amqp://',
include=['proj.tasks'])
The solution was to use the backend argument instead:
Celery('proj',
broker = 'amqp://guest:guest#localhost:5672//',
backend='amqp://',
include=['proj.tasks'])

Answer 5

Some how the console has to have django environment set up in order to pick up the settings. For example, in PyCharm you can run django console, in which everything works as expected.

Answer 6

See AMQP BACKEND SETTINGS for better understanding
Note The AMQP backend requires RabbitMQ 1.1.0 or higher to
automatically expire results. If you are running an older version of
RabbitMQ you should disable result expiration like this:
CELERY_TASK_RESULT_EXPIRES = None
Try adding the below line to your settings.py:
CELERY_TASK_RESULT_EXPIRES = 18000 # 5 hours