AMQP broadcasting for python and zope.
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.
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.
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)
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)
-Robert Niederreiter <email@example.com>