RabbitMQ

RabbitMQ is a popular and easy-to-use Message Queue.

Concepts

• Queue: A queue is a buffer that stores messages

  • Temporary Queues
    • Set queue name to empty string to use a random queue name channel.assertQueue('', {exclusive: true});

• Exchange

  • Exchange determine which queue a message goes to depending on the exchange type
  • Types
    • direct:
    • topic:
    • headers:
    • fanout: broadcast all messages it receives to all the queues it knows
      • This could be useful for logs exchange, where multiple logs consumers handles logs differently, e.g. save to different locations

• Bindings

  • Binding describes the relationship between exchange and a queue

  • Create a queue and bind the queue to exchange

    • channel.bindQueue(queue_name, 'logs', '');

  • Routing

    • Bindings can take an extra binding key parameter.

      • fanout exchanges ignores this binding key
      • In direct exchanges, messages go to the queues whose binding key exactly matches the routing key

    • channel.bindQueue(queue_name, exchange_name, 'black');

    • channel.publish(exchangeName, bindingKey, Buffer.from(msg));

• Topics

  • In topic exchange, the routing key must be a list of words, delimited by dots.
    • * (star) can substitute for exactly one word.
    • # (hash) can substitute for zero or more words.