Celery raises ValueError: not enough values to unpack

Question

Trying to run simple example with Celery and receiving an exception. RabbitMQ started in a Docker, also tried to start it locally. Celery works on a local Windows host

Answer 1

Which celery version? As far as I remember celery isn't supported in windows since celery 4

Answer 2

For Celery 4.1 on Windows.

Set an environment variable FORKED_BY_MULTIPROCESSING=1. Then you can simply run celery -A <celery module> worker.

Answer 3

It worked for me:

celery -A my_project_name worker --pool=solo -l info

basically things become single threaded and are suppoted

Answer 4

Celery 4.0+ does not officially support Windows yet. But it still works on Windows for some development/test purposes.

Use eventlet instead as below:

pip install eventlet
celery -A <module> worker -l info -P eventlet

It works for me on Windows 10 + celery 4.1 + python 3.

===== update 2018-11 =====

Eventlet has an issue on subprocess.CalledProcessError:

https://github.com/celery/celery/issues/4063

https://github.com/eventlet/eventlet/issues/357

https://github.com/eventlet/eventlet/issues/413

So try gevent instead.

pip install gevent
celery -A <module> worker -l info -P gevent

This works for me on Windows 10 + celery 4.2 + python 3.6

Answer 5

I got this error on Windows 7 32bit system. So I did this to make it work.

Add this

`os.environ.setdefault('FORKED_BY_MULTIPROCESSING', '1')` 

before defining a celery instance in myproj/settings.py file in your django project.

It should like like

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myproj.settings')
os.environ.setdefault('FORKED_BY_MULTIPROCESSING', '1')

app = Celery('tasks', broker='redis://127.0.0.1:6379/0')

I am using redis as a messaging broker so defined broker='redis://127.0.0.1:6379/0'