How do I restart celery workers gracefully?

Question

While issuing a new build to update code in workers how do I restart celery workers gracefully?

Edit: What I intend to do is to something like this

Answer 1

I have repeatedly tested the -HUP solution using an automated script, but find that about 5% of the time, the worker stops picking up new jobs after being restarted.

A more reliable solution is:

stop
start

which I have used hundreds of times now without any issues.

From within Python, you can run:

import subprocess
service_name = 'celery_service'
for command in ['stop', 'start']:
    subprocess.check_call(command + ' ' + service_name, shell=True)