What Is Publisher Subscriber Model?
Introduction
The concept of the publisher/subscriber (pub/sub) model is not new. It represents the best way for a producer, or publisher, of an information source, to communicate with an information consumer, the subscriber. This mirrors the functioning of newspapers and magazines. A publisher produces a message that contains a topic, for example, headings in newspapers, and associated content, like the associated newspaper text. Clients subscribe to the messages based on the topics or the content, or sometimes both. Unlike a newspaper, the client gets only the content that it wants. Similar to how newspapers are unaware of their readers, the publisher in the pub/sub model has no idea of which clients are getting what content. There is no direct coupling involved, which is why this particular pattern is so useful in microservice applications. In addition, communication (as with a newspaper) is asynchronous, which tends toward a more scalable solution than synchronous communication. This model is used extensively on the Internet using newer programming languages and making it possible to do much more with pub/sub than before. Using cloud-based techniques, publishers can communicate with unknown subscribers at any time and any place.
