15. Saga Choreography: от HTTP к Event-Driven архитектуре

In this video, we take the first truly architectural step in the OrderHub series: replacing the synchronous HTTP call between microservices with an asynchronous Choreography Saga. Prior to this video, we had already configured Kafka, Outbox, Debezium, and OpenTelemetry, but the most important business operation—order payment—was still performed synchronously: the client waited for a response from the payment service, and if it refused, the order was not created. We'll fix this: Remove the blocking HTTP call from the OrderService Introduce a new AWAITING_PAYMENT status Turn the payment service into a full-fledged Saga participant (Kafka consumer + producer) Add PaymentEventConsumer to the order service, which handles PaymentCompletedEvent and PaymentFailedEvent Implement a compensating transaction (cancelOrder) – instead of a rollback, we create a new action What you'll learn Why synchronous HTTP is an anti-pattern in microservices What is Saga Choreography and how it differs from Orchestration How to migrate from ACID to BASE and from rollback to compensation How to make a business operation asynchronous using Kafka and Outbox How to implement a compensating transaction in practice Timecodes: 00:00 – Introduction: The problem with synchronous HTTP 08:47 – Saga Theory (ACID vs. BASE, Choreography vs. Orchestration, Eventual) Consistency) 21:37 – OrderService Refactoring (Removing HTTP, Adding AWAITING_PAYMENT) 27:06 – Payment Service Becomes a Saga Participant 41:29 – Order Service Listens for Responses (Compensation) 51:10 – Demos 58:50 – Observability: Tracing in Jaeger 104:07 – Choreography Limitations and a Bridge to Orchestration Our Telegram channel is https://t.me/Java_for_beginner_dev. We don't claim to be completely accurate in everything said in the video; we're just learning. If you know something better and are willing to share, welcome! #java #programming #spring #SagaChoreography #EventDrivenArchitecture #Microservices #SpringBoot #Kafka #Java #DistributedSystems #SoftwareArchitecture