zamqp 1.0b1

AMQP broadcasting for python and zope.

Overview

zamqp is aimed to broadcast messages and trigger events between python instances via AMQP.

It is based on amqplib and provides consumer and producer implementations as well as a mechanism to trigger zope events remotely.

Helper Classes

Create properties for AMQP connection.

>>> from zamqp import AMQPProps
>>> props = AMQPProps(host='localhost',
...                   user='guest',
...                   password='guest',
...                   ssl=False,
...                   exchange='zamqp.broadcast.fanout',
...                   type='fanout',
...                   realm='/data')

Create AMQP connection manually.

>>> from zamqp import AMQPConnection
>>> connection = AMQPConnection('zamqp_queue', props)

Access connection channel.

>>> connection.channel

Consumer and producer

Create consumer callback.

>>> def callback(message):
...     pass # do anything with received message here

Create and start consumer thread.

>>> from zamqp import AMQPConsumer
>>> from zamqp import AMQPThread
>>> consumer = AMQPConsumer('zamqp_queue', props, callback)
>>> thread = AMQPThread(consumer)
>>> thread.start()

Create producer and send a messages. Every python object which is serializable can be used as a message.

>>> from zamqp import AMQPProducer
>>> producer = AMQPProducer('zamqp_queue', props)
>>> message = 'foo'
>>> producer(message)

Trigger events

Create an event which should be triggered in the remote instance.

>>> class MyEvent(object):
...     def __init__(self, name):
...         self.name = name

Create a listener for MyEvent. This gets called when AMQP events are received.

>>> def my_listener(event):
...     if not isinstance(event, MyEvent):
...         return
...     # do something

>>> import zope.event
>>> zope.event.subscribers.append(my_listener)

The default AMQPEventCallback just calls zope.event.notify with the received payload, which is the serialized event, in this case an instance of MyEvent.

Start our AMQP consumer for events.

>>> exchange = 'zamqp.events.fanout'
>>> queue = 'zamqp_events'
>>> from zamqp import AMQPEventCallback
>>> props = AMQPProps(exchange=exchange)
>>> callback = AMQPEventCallback()
>>> consumer = AMQPConsumer(queue, props, callback)
>>> thread = AMQPThread(consumer)
>>> thread.start()

Trigger MyEvent to AMQP channel. The previously started event consumer now receives this event and triggers it locally in it’s own interpreter.

>>> from zamqp import AMQPEvent
>>> event = AMQPEvent(queue, props, MyEvent('myevent'))
>>> zope.event.notify(event)

Credits

-Robert Niederreiter <[e-mail]>

Changes

1.0b1

• make it work [rnix]