supermyx v0.2.3

supermyx

supermyx is a highly oppionated AMQP/RabbitMQ wrapper around node-amqp and implements two messaging patterns, work queues and publish subscribe.

Installation

$ npm install supermyx --save

Work Queue Example

A work queue uses a direct exchange and contains a single queue; each consumer pulls a single message off the queue in a round robin fashion; so load is distributed evenly amongst consumers.

Producer

const producer = require('supermyx')
  .queue('amqp://localhost:5672')
  .producer;

producer.publish('build/timeline', 'get me a timeline')
  .then(() => console.log('published message to exchange'))
  .catch(err) => console.error('error %s', err));

process.on('supermyx:log', (msg) => {
  console.log('%j', msg);
});

Consumer

const consumer = require('supermyx')
  .queue('amqp://localhost:5672')
  .consumer;

consumer.subscribe('build/timeline', (data, ack) => {
  console.log('%j', data);

  // Do work here
  const ok = true;

  if (ok) {
    // message processed successfully
    ack(false, false);
  } else {
    // dead letter this message
    ack(true);
  }
});

process.on('supermyx:log', (msg) => {
  console.log('%j', msg);
});

Work Queue Configuration

Supermyx will create an exchange and queue based on the routing key passed in, so each exchange has a single work queue.

Exchange:

build.timeline.workqueue

Queue:

build/timeline

Publisher confirms

The supermyx work queue producer uses the RabbitMQ extension publisher confirms, which ensures a message is delivered to RabbitMQ, we will Promise.reject if RabbitMQ returns an error when sending a message.

Acknowledgement

The supermyx work queue consumer is configured to use acks, which ensure a message when pulled from a queue is acknowledged before removing it from the queue. supermyx will only pull 1 message of the queue at a time.

Dead letter queue

supermyx will create a dead letter exchange/queue for each exchange/queue configured, in this format:

Exchange:

build.timeline.workqueue.dead

Queue:

build/timeline/dead

Calling ack(true) from a consumer will reject a message and push the message to a dead letter queue; ack(false) will not dead letter the message.

Heartbeats

Heartbeats are configured at 60 seconds.

Reconnects

Reconnects are supported using a linear strategy, at 120ms second intervals.

Durability

Exchanges, queues and messages are durable; messages will expire after 1 hour; if not consumed.

Publish Subcribe

PubSub uses a fanout exchange, all messages published to this exchange are routed to each consumer.

Producer

const producer = require('supermyx')
  .pubsub('amqp://localhost:5672')
  .producer;

producer.publish('notify', 'get me a timeline')
  .then(() => console.log('published message to exchange'))
  .catch((err) => console.error('error %s', err));

process.on('supermyx:log', (msg) => {
  console.log('%j', msg);
});

Consumer

const consumer = require('supermyx')
  .pubsub('amqp://localhost:5672')
  .consumer;

consumer.subscribe('notify', (data, ack) => {
  console.log('%j', data);

  // Do work here
  const ok = true;

  if (ok) {
    // message processed successfully
    ack(false, false);
  } else {
    // dead letter this message
    ack(true);
  }
});

process.on('supermyx:log', (msg) => {
  console.log('%j', msg);
});

Publish Subscribe Configuration

When a consumer starts up it will create a fanout exchange and a new queue, which is exclusive, and will auto delete when the consumer ends or restarts.

Exchange:

notify.pubsub

Queue:

amq.gen-YCFBmP1pgQF8cME9Uh90Lg

Heartbeats

Heartbeats are configured at 60 seconds.

Reconnects

Reconnects are supported using a linear strategy, at 120ms second intervals.

Publisher confirms

The supermyx pubsub producer uses the RabbitMQ extension publisher confirms, which ensures a message is delivered to RabbitMQ, we will Promise.reject if RabbitMQ returns an error when sending a message.

Durability

Exchanges, queues and messages are not durable.

Logging

supermyx will emit log messages at various intervals; so you can setup a handler listening to:

process.on('supermyx:log', (msg) => {
  console.log('%j', msg);
});

You can change the log emitter handler name, like so

const options = {
  log: 'my:log'
};

const consumer = require('supermyx')
  .pubsub('amqp://localhost:5672', options)
  .consumer;

process.on('my:log', (msg) => {
  console.log('%j', msg);
});