Understanding RabbitMQ®

What is RabbitMQ®?

RabbitMQ is one of the most popular open-source message brokers: it accepts and forwards messages. It's easier to understand what makes it so important if we take the example of a post office.

What happens here? We drop off the mail we want to post at the post office! Our mail eventually gets delivered to its intended recipient. The difference between RabbitMQ and a post office is that instead of dealing with paper, it accepts, stores, and forwards binary data, called ‘messages’.

So before going on, let us first understand why we need to use a message broker. In a real system, every client wants to talk to other clients in the same or different network.

To communicate, the client has to know the other client. This is where a broker like RabbitMQ plays an important role. Instead of each client having direct knowledge about other clients, everything is grouped into the RabbitMQ server.

RabbitMQ is a general-purpose messaging solution that is used to allow web servers to quickly respond to requests rather than making the user wait while performing the procedures to handle requests. It is an open-source, distributed message queue.

How does RabbitMQ® work?

Time to understand how it works. RabbitMQ is an implementation of an open-source standard protocol for messaging for Advanced Message Queuing Protocol (AMQP). AMQP standardizes messaging using their concepts of Producers, Broker,s and Consumers.

The advantage of implementing this widely-accepted protocol is that it increases loose coupling and scalability, as well as compatibility with previously existing libraries.

In AMQP (and thus in RabbitMQ), a Producer is the one who sends the message. A Broker here can be thought of as a messaging queue. Think of it as the name of a postbox that resides in RabbitMQ.

However, it never uses the queue directly, instead using an exchange. The exchange forwards the messages to the queue. The role of a Consumer is to pick up the message from this queue.

The queue is a large message buffer. It is only bounded by the host’s memory and disk limits. It’s not a compulsion that the Producer, Consumer, and…