Microsoft Azure offers a very powerful and cheap queueing system based on Azure Storage. As a node developer the challenge is to build a simple to use system which is able to consume messages from the azure queue. The Azure Cost Monitor is for instance using this module to process all costs analytic tasks in the backend.

The module azure-queue-client is able to implement this in a couple of simple steps. It supports multiple workers in different processes and on different machines. The following example illustrates the usage:

// config with your settings
var qName = ‘<<YOURQUEUENAME>>’;
var qStorageAccount = ‘<<YOURACCOUNTNAME>>’;
var qStorageSecret = ‘<<YOURACCOUNTSECRET>>’;
var qPolling = 2;

// load the modules
var queueListener = require(‘azure-queue-client’).AzureQueueListener;
var q = require(“Q”);

// establish a message handler
queueListener.onMessage(function(message) {
  var defer = q.defer();

console.log(‘Message received: ‘ + JSON.stringify(message));
defer.resolve();

return defer.promise;
});

// start the listening
queueListener.listen(qName, qStorageAccount, qStorageSecret, qPolling, null);

Developers who are using the Azure Scheduler might recognize that the payload of the scheduler is encapsulated in a XML wrapper. This XML wrapper can be handled by the module as well so that it doesn’t matter if the message comes from an other queue client or the Azure Scheduler.

This module makes writing job workers in node, hosted on Azure or any other cloud provider a breeze.