Message queues and publish-subscribe

Message queues and publish-subscribe (Pub/Sub) are communication patterns commonly used in microservices architectures to facilitate asynchronous communication between services.

Message queues

A message queue is a communication mechanism that allows microservices to send and receive messages asynchronously. Messages are placed in a queue by the sender and processed by the receiver.

Here are some of its use cases:

• Task distribution: A web application that processes user-uploaded files. Each file processing task is placed in a message queue, and multiple worker processes consume tasks from the queue to handle file processing concurrently.
• Event sourcing: A system that maintains a log of events to capture changes in state. Events are published to a message queue, and various microservices subscribe to these events to update their own state.
• Microservices communication: A system with multiple microservices where one microservice...