avdkishore / node-rabbitmq-client

Rabbitmq client with connection strategies in place

Connection management for rabbitmq client

Node js Rabbit MQ client which has connection management backed into it. This project is written on top of amqp-connection-manager.

Features

• Automatically reconnect when your amqplib broker dies in a fire.
• Round-robin connections between multiple brokers in a cluster.
• If messages are sent while the broker is unavailable, queues messages in memory until we reconnect.
• Very un-opinionated library - a thin wrapper around amqplib.

Usage

Using yarn: yarn add node-rabbitmq-client Using npm: npm install node-rabbitmq-client

const RabbitMQClient = require('node-rabbitmq-client');

/**
 * options is the object which is passed to consume at the time of initialization
 *
 * options = {
 *    queue: {
 *      name: 'some-queue-name'
 *   }
 * }
 */

const { publish, consume, purgeQueue, ackAll } = RabbitMQClient;

/* to publish a message */
publish({ queue: { name: 'some name' } }, data);
`data` is JS object

/* to consume from a queue */
consume({ queue: { name: 'some name' } }, promiseHandler);

/* to purge a queue */
purge({ queue: { name: 'some name' } });

/* to ack all messages */
ackAll();

Please read this for implementing consume

• promiseHandler for consume should always return a resolved Promise even if some operations on the received message fails.
• When returning a resolved Promise, parameters need not be passed to it.If passed, these are simply ignored.
• Best practice is to implement a catch handler for the promiseHandler and push to some other queue and return a resolved Promise from there.
• If parsing the JSON message fails while consuming, this will try to push this error to another queue parsingErrors. So, if this failure is to be handled and noted, provide parsingErrors queue in the same config. (This is optional. Whether or not queue is provided, the error will be logged);
• promiseHandler gets the message and the options that were passed to consume intially

/**
 *
  options is the object which is passed to consume at the time of initialization
  {
    queue: {
      name: 'some-queue-name',
      messagePriority: message priority (1-10), // set if the queue is a priority queue. It is optional
      options: {
        arguments: {
          'x-max-priority': queue priority (1- 10) // set to make the queue a priority queue. It is optional
        }
      }
    }
  }
 */
promiseFunction(message, options)
  .then(data => {
    /* once processing the message is successful, return resolved promise */
    /* if status queue is provided and success should be recorded */
    if (statusQueue && recordSuccess) {
      publish(statusQueue, {
        status: 'success',
        queueName,
        message: data
      });
    }

    /* this is needed to ack to the channel regarding this message */
    return Promise.resolve();
  })
  .catch(error => {
    if (statusQueue && recordError) {
      /* if status queue is provided and failure should be recorded */
      publish(statusQueue, {
        status: 'error',
        queueName,
        error,
        message
      }).then(() => channel.ack(msg));
    }
    logger.log('error', {
      note: `Error while processing the message from ${queueName}`,
      error: error
    });

    /* return resolved Promise from here */
    return Promise.resolve();
  });

Configuration

By default, this looks at /config/env/${NODE_ENV} file for rabbitMQ configuration If configuration is not found here, then it looks at /src/config/env/${NODE_ENV}

config = {
  rabbitMQ: {
    host: process.env.PUBSUB_RABBITMQ_SERVICE_HOST,
    port: process.env.PUBSUB_RABBITMQ_SERVICE_PORT_AMQP || 5672,
    username: process.env.RABBITMQ_USERNAME,
    password: process.env.RABBITMQ_PASSWORD,
    prefetch: process.env.PREFETCH_JOBS || 2,
    vhost: process.env.VHOST || '/',
    heartbeatInterval: process.env.HEARTBEAT || 5,
    reconnectTime: process.env.RECONNECT_TIME || 10,
    protocol: process.env.RABBITMQ_PROTOCOL || 'amqp',
    defaultQueueFeatures: { durable: true }
  }
}