What are message brokers?

Message brokers are middleware software that enable applications to communicate asynchronously. They act as intermediaries, receiving messages from publishers and delivering them to subscribers or consumers.

Key concepts:

• Queues: Messages are sent to a queue, from which one or more consumers retrieve them. The "first in, first out" (FIFO) principle is usually applied.
• Topics: Messages are published to a topic, and all subscribers to that topic receive a copy of the message (publish/subscribe model - pub/sub).

Advantages of using:

• Asynchrony: The sender does not wait for the message to be processed by the receiver, increasing performance.
• Decoupling: Senders and receivers do not know about each other directly, simplifying development and scaling.
• Reliability: Brokers typically ensure guaranteed message delivery, even if the receiver is temporarily unavailable.
• Scalability: Systems can be easily scaled by adding new sender or receiver instances.
• Routing: Flexible message routing based on various criteria.

Examples of message brokers:

• RabbitMQ
• Apache Kafka
• ActiveMQ
• Redis Pub/Sub

# Example of connection configuration in an application
message_broker:
  type: rabbitmq
  host: localhost
  port: 5672
  queue_name: order_processing