Building a Microservices Ecosystem with Kafka Streams and KSQL

This text delves into building event-driven microservices using Apache Kafka's Streams API. It discusses the advantages of making systems event-driven, emphasizing decoupling and the ability to store events as facts that represent a business narrative over time. The text also explores the use of streaming platforms like Kafka for managing statefulness in services, handling consistency issues, and using declarative and functional methods for stream processing. It presents an example of building a simple order management system with Kafka Streams, addressing challenges such as blending streams and tables, reading own writes, and maintaining consistency in a distributed environment. The text also discusses the use of KSQL for stateful stream processing off the JVM and provides examples of more complex microservices like an Inventory Service that performs atomic operations across multiple threads or machines. It concludes by highlighting the advantages of using streaming platforms to handle both micro and macro architectures, while acknowledging potential drawbacks such as increased complexity and latency.