Nathan Borror

I recently installed RabbitMQ to handle some message queuing needs at Readernaut and thought I’d share how everything came together. If you’d like to learn more about RabbitMQ please read the excellent Rabbits and Warrens.

To use RabbitMQ with python you need amqplib because Rabbit uses the AMQP standard. To make amqplib a little easier to use I needed a simple script that did three things:

• Easy way to connect to RabbitMQ.
• Easy way to pull stuff out of the queue.
• Easy way to throw stuff into the queue.

There’s a project called Carrot which handles all this and much more but it’s a little too complex for what I’m doing. All I needed was something very small, straightforward, and EASY.

After staring at Carrot for a few days I decided to distill down what I needed into a single script I’m calling Flopsy (this is what happens when you’re coding and watching a movie about Beatrix Potter, right?). So here we go:

Step 1: Set global variables:

AMQP_SERVER = 'localhost'
AMQP_PORT = 5672
AMQP_USER = 'guest'
AMQP_PASSWORD = 'guest'
AMQP_VHOST = '/'

Step 2: Create a consumer (a script that consumes messages from the queue):

>>> from flopsy import Connection, Consumer
>>> consumer = Consumer(connection=Connection())
>>> consumer.declare(queue='books', exchange='readernaut', routing_key='importer', auto_delete=False)

>>> def message_callback(message):
...     print 'Recieved: ' + message.body
...     consumer.channel.basic_ack(message.delivery_tag)
>>>
>>> consumer.register(message_callback)
>>> consumer.wait()

Step 3: Create a publisher (a script that publishes messages to the queue):

>>> from flopsy import Connection, Publisher
>>> publisher = Publisher(connection=Connection(), exchange='readernaut', routing_key='importer')
>>> publisher.publish('Test message!')
>>> publisher.close()

And there we go! Flopsy weighs in at under 80 lines of code and it can be found on Github. Most of the above will make a lot more sense after reading the Rabbits and Warrens article and investigating RabbitMQ.

Update: I just realized, this isn’t at all Django specific so my title is a little misleading (changing). That said, you could most certainly use Flopsy with straight up Python :)