celery 'Worker-n' pid:xxxx exited with 'exitcode 1' when I import hmmlearn

Question

In my tasks.py file, when I import hmmlearn,

from hmmlearn import hmm

and start my celery workers, I get the following error

Answer 1

I just stumbled upon a similar situation. Upgrading billiard to 3.5, as suggested in a different answer, was not an option (because it conflicts with Celery==3.1.25 and I prefer that particular version for Windows its support).

I figured out, however, that in my case the problem was most probably due to this issue - it occurred only when I tried to import anything from sklearn in the Worker's process.

The problem was resolved by adding this snippet before the imports from sklearn:

from multiprocessing import current_process
try:
    current_process()._config
except AttributeError:
    current_process()._config = {'semprefix': '/mp'}

Answer 2

This might be because celery 3.1.xx comes bundled with billiard 3.3.

If you upgrade that package (to 3.5 at time of writing), the service might work again.

pip install --upgrade billiard