django DEBUG设置为False时，Celery没有看到任务

Question

I've got a Django application with Celery. Tasks are described in tasks.py files with @shared_task in different apps, each has its own AppConfig and is being installed (added to INSTALLED_APP) correctly.

Everything worked fine until I turned DEBUG off. Celery started to fail due to tasks of unregistered type. With the DEBUG variable Celery can see all of my tasks and work correctly.

EDIT: My celery.py code is as following:

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

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'core.settings')

app = Celery('APP')
app.config_from_object('django.conf:settings', namespace='CELERY')

app.autodiscover_tasks()

@app.task(bind=True)
def debug_task(self):
    print('Request: {0!r}'.format(self.request))

Running manage.py check shows no errors, all config files and logs have correct rights.

What can cause such a bug?

Answer 1

The thing that was causing such a strange bug was my log files permissions.

I have the following in my settings.py:

if not DEBUG:
    WORKER_HANDLERS = {}
    for app in PROJECT_APPS:
        WORKER_HANDLERS['file_{0}'.format(app)] = {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '/var/log/app/{0}.log'.format(app),
        }

    LOGGING['handlers'].update(WORKER_HANDLERS)

While installing my DEBIAN package in postinst script, i was calling collectstatic command from root, which created all of my log files owned by root.

That's why celery failed to run: actually there was an error starting my app.

Yet strange thing is that manage.py check was saying everything was ok.

Be careful with file permissions on log files.