Celery doesn't see the redis broker

Question

I am trying to use Celery with Redis.

It is my celery.py file:

from __future__ import absolute_import
from celery import Celery

celery=Celery(include=[ 'tasks.chatterbox' ])

# import celery config file
celery.config_from_object('celeryconfig')

if __name__ == '__main__':
    celery.start()

It is my celeryconfig.py file:

BROKER_URL = 'redis://localhost:6379/0'

# redis backend
CELERY_RESULT_BACKEND = 'redis://'

And when I run:

celery -A broker.celery worker -l info

I got this error:

Traceback (most recent call last):
  File "/usr/local/bin/celery", line 9, in <module>
    load_entry_point('celery==3.1.11', 'console_scripts', 'celery')()
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/__main__.py", line 30, in main
    main()
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/celery.py", line 81, in main
    cmd.execute_from_commandline(argv)
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/celery.py", line 769, in execute_from_commandline
    super(CeleryCommand, self).execute_from_commandline(argv)))
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/base.py", line 306, in execute_from_commandline
    return self.handle_argv(self.prog_name, argv[1:])
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/celery.py", line 761, in handle_argv
    return self.execute(command, argv)
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/celery.py", line 693, in execute
    ).run_from_argv(self.prog_name, argv[1:], command=argv[0])
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/worker.py", line 179, in run_from_argv
    return self(*args, **options)
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/base.py", line 269, in __call__
    ret = self.run(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/bin/worker.py", line 212, in run
    state_db=self.node_format(state_db, hostname), **kwargs
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/worker/__init__.py", line 100, in __init__
    self.setup_instance(**self.prepare_args(**kwargs))
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/worker/__init__.py", line 126, in setup_instance
    self.should_use_eventloop() if use_eventloop is None
  File "/usr/local/lib/python2.7/dist-packages/celery-3.1.11-py2.7.egg/celery/worker/__init__.py", line 245, in should_use_eventloop
    self._conninfo.is_evented and not self.app.IS_WINDOWS)
  File "/usr/local/lib/python2.7/dist-packages/kombu-3.0.16-py2.7.egg/kombu/connection.py", line 836, in is_evented
    return self.transport.supports_ev
  File "/usr/local/lib/python2.7/dist-packages/kombu-3.0.16-py2.7.egg/kombu/connection.py", line 786, in transport
    self._transport = self.create_transport()
  File "/usr/local/lib/python2.7/dist-packages/kombu-3.0.16-py2.7.egg/kombu/connection.py", line 518, in create_transport
    return self.get_transport_cls()(client=self)
  File "/usr/local/lib/python2.7/dist-packages/kombu-3.0.16-py2.7.egg/kombu/transport/redis.py", line 916, in __init__
    self.connection_errors, self.channel_errors = self._get_errors()
  File "/usr/local/lib/python2.7/dist-packages/kombu-3.0.16-py2.7.egg/kombu/transport/redis.py", line 954, in _get_errors
    return get_redis_error_classes()
  File "/usr/local/lib/python2.7/dist-packages/kombu-3.0.16-py2.7.egg/kombu/transport/redis.py", line 78, in get_redis_error_classes
    from redis import exceptions
ImportError: No module named redis

Finally, it is my project structure:

.
├── __init__.py
├── celeryconfig.py
├── broker
│   ├── celery.py
│   ├── __init__.py    
├── tasks
    ├── chatterbox.py
    ├── __init__.py

I am using:

• Celery 3.1.11
• Redis 2.8.8

Answer 1

The error trace states the cause clearly (as usual, reading it bottom up)

ImportError: No module named redis

You can check, if redis is installed

Using pip

$ pip freeze

The output shall contain a line starting with redis=

Install redis:

$ pip install redis

I use virtualenv and sometime forget to switch to proper environment. In those cases I miss the module I expect to be present. Then I simply switch to proper virtual env or install the missing module.

PS: Basic trick for becoming an expert is reading error messages and following it.