A message broker is a type of software that allows applications, systems, and services to communicate and exchange information. This is done by translating messages between formal messaging protocols, which in turn allows interdependent services to communicate directly despite being written in different languages or being on different platforms.
The software modules within messaging middleware are message brokers. They can validate, store, route, and deliver messages to the appropriate destinations. Brokers act as intermediaries between applications to allow the deployment of messages by senders without knowing where, how many, or whether or not receivers are active. Message brokers rely on a message queue to reliably store messages and guarantee delivery. Messages are stored in a message queue in the order they are published and remain in the queue until receipt is confirmed.
Some of the most popular message brokers include Apache Kafka, Redis, RabbitMq, ActiveMQ, and Krestel, each of which has different scalability, data persistency, data capabilities, and consumer capabilities. Applications use messaging middleware to simplify the challenge of communication and create a common communication infrastructure that’s scalable.
The Benefits of Message Queues
There are several benefits of utilizing message queues. They enable asynchronous message deployment, meaning the endpoints that produce and consume messages interact with the queue. Producers can continuously add messages to the queue without the need for confirmation of receipt by a receiver. Consumers process messages when they are available, which means there’s no need to wait to produce messages.
Queues provide increased reliability by ensuring consistent data quality and reducing errors when parts of the system are offline. Separating different components with message queues creates higher fault tolerance. This means that if one part of the system is inaccessible, the other part can continue working with the queue. Organizations can leverage granular scalability with message queues. Even when workloads peak, it’s possible to add requests to the queue without the risk of interference. Workloads can be distributed across consumers as the queues grow.
Message queues offer simplified decoupling and remove dependencies between components. Rather than software components being bogged down with communications code, they can be designed for more discrete business functions. They are a simple way to decouple distributed systems on monolithic applications, microservices, or serverless architectures.
Publish and Subscribe Messaging
With a publish and subscribe message system, producers publish messages on a topic thread. Producers publish messages that are consumed by subscribers. Multiple publishers can publish messages on the same topic thread, and any given message can be received by many subscribers. When subscribers subscribe to topic threads, they receive all messages published on the topic. This is known as an asynchronous message.
Point to Point Communication
Point-to-point communications have one publisher and one subscriber. This type of messaging uses a queue to store deployed messages until they are received by the consumer. The producer sends a message to the queue where the message consumer retrieves it and sends an acknowledgment receipt. Multiple producers can send messages to the queue where more than one message consumer can retrieve messages.
There are several use cases for message brokers including financial transactions and payment processing, e-commerce order processing and fulfillment, and protecting sensitive data at rest and in motion. A message broker is an integration solution that allows a producer to send messages to a server that can provide data marshaling, routing, message translation, persistence, and deployment to the appropriate destinations, or message consumers.
The key characteristic of a message broker is that it’s a discrete service. Producers and consumers communicate using messaging protocols. Brokers provide the necessary management and tracking of clients so that individual applications don’t have to deal with the complexity of message delivery.