gen_amqp

####License: MIT ####Copyright: 2012, 2013 SiftLogic LLC http://siftlogic.com

gen_amqp is a behaviour for easier AMQP connection handling. It extends the gen_server behaviour with the additional callbacks of handle_basic_deliver/3 and handle_basic_cancel/2. In addition to this there are several wrappers for setting up connections, exchanges, and queues. Also included are tools for polling and subscribing.

gen_amqp uses RabbitMQ as the AMQP client, but the interface is written in a backend agnostic way and it should be relatively straight forward to replace it with another 0-9-1 AMQP client implementation. Or possibly even a similar solution such as ZeroMQ.

Usage

The simplest way to use gen_amqp is to implement the behaviour callbacks together with subscribing to a queue.

Add a call to gen_amqp:connect in the init function, store the returned connection in State and add a gen_amqp:disconnect in terminate.

After setting up a subscription using gen_amqp:subscribe_nocreate/3 every message from the amqp server will result in a call to handle_basic_deliver/3. Handle the message and ack using gen_amqp:ack/2 and that's about it.

Functions

Callbacks

A module implementing the gen_amqp behaviour, should implement all the standard callbacks for a gen_server. In addition to those, the following callbacks are expected.

handle_basic_deliver(Tag, Data, State)

Receive and process message containing Data. After processing is completed you manually have to ack the message using gen_amqp:ack(Connection, Tag). This function should return the same result as gen_server:handle_cast/2.

Types:

Return types are the same as gen_server:handle_cast/2

Tag = opaque()
Data = any()
State = any()

handle_basic_cancel(Tag, State)

For handling basic.cancel messages from the AMQP server. This function should return the same result as gen_server:handle_cast/2.

Types:

Return types are the same as gen_server:handle_cast/2