amqp-wrapper

amqp-wrapper

A simple wrapper to https://github.com/squaremo/amqp.node.

Allows you to have any number of publish queues, one consume queue and to perform consume and publish operations.

• You can specify a queue which will be declared (made to exist). This will be the queue from which you will consume.
• If you specify a routing key for the queue, then a binding will be set up (I.e. a mapping that tells AMQP to route message with that routing key to that queue on the exchange you have specified).
• Any options you specify at the per-queue level are passed directly through to ch.assertQueue in the underlying library. If you want to set up dead lettering, for example, then pass the deadLetterExchange option which will cause the queue to be declared with that dead letter exchange.
• deadLetterExchange and deadLetterRoutingKey are special options, in that as well as being passed through to ch.assertQueue() to ensure the dead lettering behaviour occurs, a queue will be declared of the same name with the -dead-letter suffix, with a binding declared on the dead letter exchange for the dead letter routing key. This means that when a message is dead lettered on that queue it will have somewhere to go without you having to set up a dead lettering queue manually.

Example usage

var AMQP = require('amqp-wrapper');

var config = {
  url: process.env.AMQP_URL,
  exchange: process.env.AMQP_EXCHANGE,
  queue: {
    name: process.env.AMQP_CONSUME,
    routingKey: process.env.AMQP_ROUTING_KEY, // If supplied, queue is bound to
    // this key (or keys) on the exchange. NB Can be an array of string or just
    // a string.
    options: {/* ... */} // options passed to ch.assertQueue() in wrapped lib.
  },
  // Set the QOS/prefetch.
  prefetch: 100
};

var amqp = AMQP(config);

// Must call this before you consume/publish/etc...
amqp.connect(amqpConnectDone);

// Consuming
var handleMessage = function(message, callback) {
	//...
};
// You must call:
callback(err, requeue)
// in your handleMessage. If `err` !== `null` then the message will be `nack`ed.
// Requeueing will be requeue iff `requeue` is `true`.
// If `err` is `null` then the message is `ack`ed.
// If an exception occurs in handleMessage, then the message is `nack`ed and not requeued.

// Start consuming:
amqp.consume(handleMessage);

// Publishing to arbitrary routing key.
amqp.publish(routingKey, payload, options, done);

If payload is an object, it will be turned into JSON.

Tests

Start a rabbit server, preferably a 'throw away' one with fresh state. You can do this like so if you have docker:

docker run --rm -p 5672:5672 dockerfile/rabbitmq

Then:

npm test

Note that tests/config.js currently assumes you are using boot2docker (on a Mac) so you may need to hack that stuff (or it may just work as it should just use localhost if it's not there... unproven though.)

Promises

connect() and publish() support promises too. If you don't give a callback, they'll return a promise!

License

(The MIT License)

Copyright (c) 2014 Noble Samurai

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.