Presentation: Complex Event Flows in Distributed Systems

Event-driven architectures enable nicely decoupled microservices and are fundamental for decentralized data management. However, using peer-to-peer event chains to implement complex end-to-end logic crossing service boundaries can accidentally increase coupling. Extracting such business logic into dedicated services reduces coupling and allows to keep sight of larger-scale flows - without violating bounded contexts, harming service autonomy or introducing god services. Service boundaries get clearer and service APIs get smarter by focusing on their potentially long running nature. I will demonstrate how the new generation of lightweight and highly-scalable state machines ease the implementation of long running services. Based on my real-life experiences, I will share how to handle complex logic and flows which require proper reactions on failures, timeouts and compensating actions and I provide guidance backed by code examples to illustrate alternative approaches.