Implement RabbitMQ in Nodejs

Posted By : Ankit Uniyal | 28-Jun-2018

nodejs

In this blog, we will cover how we can connect to RabbitMQ, publish message to message queue and consume message from message queue. But before moving forward, let us understand what is RabbitMQ and how it works.

RabbitMQ is basically a message queue software through which we can exchange data between processes, applications and servers.In Simple terms, it is a software where we can define queues and application can connect to the queue and publish message onto it.

Let's take an example where a pizza outlet allows the customer to order pizza online and each request is added as a message to the queue and consume by the receiving application. As each order is picked from message queue and after the deliver its status marked as done in database.

How to Install RabbitMQ in Ubuntu :

Below are the command which needs to be run one by one to install RabbitMQ in Ubuntu :

sudo apt-get install rabbitmq-server -q -y --force-yes

sudo rabbitmq-plugins enable rabbitmq_management

sudo rabbitmqctl add_user your_username yourpassword

sudo rabbitmqctl set_user_tags your_username administrator

sudo rabbitmqctl set_permissions your_username ".*" ".*" ".*"

sudo service rabbitmq-server restart

How to set up connection to RabbitMQ and consume message from Message queue using Nodejs :

We are using 'amqlib' npm module.

  var amqp = require('amqplib/callback_api');
  var amqpConn = null;
  amqp.connect('amqp://localhost', function(err, conn) {
      conn.createChannel(function(err, ch) {
          ch.assertQueue(queueName, {
              durable: true
          });
          console.log(" [*] Waiting for messages in %s. To exit press CTRL+C", queueName);
          ch.consume(configurationHolder.config.queueName, function(msg) {
              console.log(" [x] Received %s", msg.content.toString());
              Promise.delay(500);
              conn.close();
              return msg.content.toString();
          }, {
              noAck: true
          });
      });
  });

Next, how we can publish message to RabbitMQ message queue :

var amqp = require('amqplib/callback_api');
amqp.connect('amqp://localhost', function(err, conn) {
    conn.createChannel(function(err, ch) {
        var msg = 'Hello World!';
        ch.assertQueue(queueName, {
            durable: false
        });
        ch.sendToQueue(q, new Buffer(msg));
        console.log(" [x] Sent %s", msg);
    });
    Promise.delay(500);
    conn.close();
});

Thanks.