A Survey of Publish/Subscribe Middleware Systems for Microservice Communication

In today's industrial and academic research area, the publish/subscribe (pub/sub) communication paradigm is gaining attention. Due to its capacity to decouple communication entities in time, space, and synchronization, it is a useful interaction mechanism for large-scale distributed systems. Rather than interacting directly with one another, services in the pub/sub pattern can communicate through a message broker. This approach separates the concerns of publishers and subscribers, allowing publishers to concentrate just on publishing and subscribers to concentrate solely on the publications to which they are subscribed. The resulting structure enables asynchronous message sending and receiving by a task-specific broker, which is one of the various approaches to construct event-based systems. Because of their unique qualities, including data-centricity, dynamicity, and many-to-many communications, the decoupling properties are well-suited for Microservices. Components of a monolithic application call each other using language-level method or function calls. A microservices-based application, on the other hand, is a distributed system that runs on numerous machines. Typically, each service instance is a process. There are numerous advantages to using the Microservices Architecture design. It begins by addressing the issue of complexity. It breaks down what would otherwise be a massive monolithic application into a series of services. While the overall functionality of the application has not changed, it has been divided into digestible parts or services. A significant disadvantage of microservices is the increased complexity that comes with being a distributed system. Developers must choose and implement a messaging or Remote procedure call-based interprocess communication mechanism. As a result, services must communicate through the interprocess communication (IPC) method. The Pub/Sub communication model, a powerful interprocess communication technique has been utilized in several studies. We examine the Pub/Sub interaction paradigm in the context of Communication for Microservices in this study.