The stability and speed of an application or website are certainly among the most important factors for users. Who has never left a site before even seeing the first page because it took too long?
What is RabbitMQ
RabbitMQ is an open-source, distributed, and scalable messaging broker which serves as an intermediary for efficient communication between producers and consumers. RabbitMQ implements the application layer messaging protocol AMQP, which is focused on communicating asynchronous messages with delivery guarantee through confirmations of receipt of messages from the broker to the producer and from the consumers to the producer.
How does RabbitHQ work
In a simplified way, RabbitMQ defines queues that will store messages sent by producers until consuming applications get the message and process it. It allows us to design and implement distributed systems, in which a system is divided into independent modules that communicate with each other through messages. Like all communication, we need a producer, a message, and a receiver. In the middle of the cake is RabbitMQ, which would be the place where the message is waiting for the receiver. Let’s better understand how it works by knowing the types of exchanges representing the exchange of messages.
Exchange Types
Through exchanges, whenever we send a message via RabbitMQ, we do not send it directly to a queue; for other systems to read it, we send it to an exchange, which is responsible for forwarding messages to different queues. The types of exchanges are Direct, Fanout, Topic, and Readers.
Direct Exchange
Suppose a producer needs to issue a purchase confirmation message to three consumers. That is, the system needs to communicate with three other different systems to make the purchase. As RabbitMQ sends the message separately to each queue, there is momentum to make these other systems receive the message directly. Normally the exchange forwards the message to the queues, but we often don’t want our messages to be sent to all the queues. Therefore, there are several conditions that we can apply to make an exchange work. So you can have your message sent to just one consumer; instead of being sent to everyone. Binding Key: To connect a queue to an exchange, you need to create a bind, a relationship between a queue and an exchange, like a connector. Routing Key: In this bind, we can also create an element called a routing key, which in other words, is a key to forwarding our messages to a specific queue. If you have a routing key X, a routing key Y, and a routing key Z, the message with routing key Y, for example, will go through queue Y and be delivered directly to the consumer you defined to receive the message. This way, we can have several queues connected to an exchange, but at the same time, they can also have different relationships with the exchanges using the routing keys.
Fanout Exchange
When the message is sent to the exchange, it is sent to all queues connected to it. So if you have 10 queues connected to a fanout exchange, all queues will receive the message that was sent.
Topic Exchange
It is one of the most flexible exchanges, allowing us to send messages according to the subject. And based on the way you name the routing keys, it is possible to create patterns of rules and relationships between systems. For example: routing key (x.); routing key(.z); routing key (.y.).
What is AQMP in RabbitMQ
AMQP (Advanced Message Queuing Protocol) is an open messaging protocol used to define the transport of messages between multiple applications. It is similar to the HTTP and TCP protocols in that it is a wire-level protocol, except that it allows for asynchronous transport. RabbitMQ chose to implement AMQP for several reasons. The first is that this protocol is described as a standard for middleware, unlike JMS, which defines an API. An international consortium, including large companies like Red Hat, Cisco Systems, and Microsoft, wrote this AMQP Specification. The second is the interoperability of this protocol, which allows any application implementing AMQP to communicate with an AMQP broker. AMQP is not the only protocol used by RabbitMQ. The image below represents all the protocols, languages , and APIs implemented and/or supported by RabbitMQ.
Best Features of RabbitMQ
In addition to allowing the integration of different applications through messages asynchronously and from different locations, RabbitMQ offers us other features that have made it very popular within the world of messaging brokers:
Reliable Storage
RabbitMQ incorporates several features that allow it to guarantee message delivery. Among these, it provides storage when no consumers can receive the message. It allows consumers to accept the delivery of the message to ensure that it has been processed successfully. If the processing fails, RabbitMQ allows the message to be re-queued to be consumed by a different instance of the consumer or be processed again by the same consumer that initially failed when it recovers. RabbitMQ also guarantees the delivery order of the messages; that is, they are consumed in the same order in which they arrived in the RabbitMQ queues.
Creation of clusters
Although RabbitMQ provides great performance by processing thousands of messages per second, sometimes it needs to be able to process larger numbers of messages without impacting application performance. For this, RabbitMQ allows the creation of clusters to scale the solution horizontally, which is transparent to both producers and consumers.
Highly Available Queues
In RabbitMQ, queues can be replicated across multiple nodes in a cluster, assuring that in the event of a node failure or downtime, the broker can continue to receive messages from producers and deliver them to the appropriate consumers.
Flexible routing
In RabbitMQ, flexible routing rules can be defined, even following a certain pattern, to route messages between exchanges and queues, through bindings.
Multiple protocol support
Besides supporting the AMQP protocol, RabbitMQ supports STOMP, MQTT, and HTTP through plugins. It also incorporates authentication and access control mechanisms for each broker’s components.
Real-life Use Cases of RabbitMQ
The most important use cases of RabbitMQ are making possible the guarantee of asynchronicity between applications, reducing the coupling between applications, distributing alerts, and controlling the queue of jobs in the background. However, the practical use cases of RabbitMQ are in eCommerce, where t is used to manipulate, process, and forward your sales orders to systems in other sectors, such as distribution and issuing invoices. When processing orders, you can forward your sales message to the distribution center and an invoice area. In this scheme, everything works horizontally, following the asynchronous pattern for sending messages, but it is often possible to send an action to several queues. Following the previous example, this function can be very useful when the customer makes a purchase and the product needs to be prepared for distribution, transport, and invoices. And since each of these sectors is a different system, RabbitMQ’s goal is to forward all these messages to the corresponding systems.
Rabbit MQ alternatives:
RabbitMQ is a lot simpler than it looks, and there are several alternatives to it which include:
#1. IronMQ
IronMQ is super-fast message queuing software. It is highly available, durable in design, and preferably for a one-time delivery. IronMQ is the most powerful cloud-native solution for modern application architecture. It supports push queues, pull queues, and long polls, which keeps poll requests open longer. Moreover, it can use multiple high-availability data centers, which facilitates scalability. You can deploy in the cloud, on shared or dedicated hardware, or on-premises. It also has a range of client libraries with easy-to-read documentation.
#2. Apache Kafka
Kafka is a platform with a strong presence in distributed event streaming. At its core, Kafka is designed as a replicated, distributed, persistent commit log. Its greatest usability is to event-driven power microservices or large-scale stream processing applications, automatically replicating events asynchronously within the cluster to fault tolerance and high availability.
#3. Apache ActiveMQ
ActiveMQ is a Java-based multiprotocol Message Broker. With it, we can integrate applications using the AMQP message queuing protocol at the application layer. It implements several protocols for integration, such as JMS (native Java) and Stomp (which can be used by PHP applications), among others.
Final Words
Messaging brokers have traditionally been an important piece within the architectures of organizations. Still, with the increase in users entering company systems through different channels, products are needed that allow them to be scaled horizontally at a low cost. Allowing the processing of a large number of messages per second. This is where a new generation of brokers, such as RabbitMQ, are becoming more relevant in modern applications, which seek to offer high levels of availability, reliability, interoperability, and performance to our clients. You may also explore some reliable RabbitMQ hosting platforms for your application.
