Publisher Subscriber Pattern
- One way messaging pattern that involves multiple subscribers who can listen to messages
- Messages are generated by a publisher and can be categorized by topic
- Subscribers can recieve messages as per topic subscriptions
- Similar in concept to the observer pattern
- A message broker facilitates transport of messages between the publisher and the subscribers
- Brokers such as RabbitMQ and ActiveMQ Apollo are popular in the enterprise world
- Useful when working with Microservices and serverless architectures
- Message deliverability may post issues if the broker goes down, misconfigured or crashes