UPDATE: Update rq/worker.py to remove os.fork() calls so that this code can work on windows. Currently this code is working fine on windows but sometimes worker needs to be restarted as it is not picking the tasks.

RQ (Redis Queue) is a simple Python library for queueing jobs and processing them in the background with workers. It is backed by Redis and it is designed to have a low barrier to entry. It should be integrated in your web stack easily.

First, run a Redis server, of course:

$ redis-server

To put jobs on queues, you don't have to do anything special, just define your typically lengthy or blocking function:

import requests

def count_words_at_url(url):
    """Just an example function that's called async."""
    resp = requests.get(url)
    return len(resp.text.split())

You do use the excellent requests package, don't you?

Then, create a RQ queue:

from rq import Queue, use_connection
use_connection()
q = Queue()

And enqueue the function call:

from my_module import count_words_at_url
result = q.enqueue(count_words_at_url, 'http://nvie.com')

For a more complete example, refer to the docs. But this is the essence.

To start executing enqueued function calls in the background, start a worker from your project's directory:

$ rqworker
*** Listening for work on default
Got count_words_at_url('http://nvie.com') from default
Job result = 818
*** Listening for work on default

That's about it.

Simply use the following command to install the latest released version:

pip install rq

If you want the cutting edge version (that may well be broken), use this:

pip install -e git+git@github.com:nvie/rq.git@master#egg=rq

This project has been inspired by the good parts of Celery, Resque and this snippet, and has been created as a lightweight alternative to the heaviness of Celery or other AMQP-based queueing implementations.