Chapter 17 — Orchestration-Driven Service-Oriented Architecture (SOA)

Core ideas

• The historical, enterprise-wide SOA driven by an ESB (Enterprise Service Bus) and heavy orchestration. Taxonomy of service types: business services, enterprise services, application services, infrastructure services, plus the orchestration engine.
• Chief driver was reuse — which, taken to the extreme, produced brittle, over-coupled systems where a single business request fanned out across many shared services.

Trade-offs / when to use

Largely presented as a cautionary tale — why the industry moved away from it. Understand it to understand why microservices reacted against reuse-at-all-costs and central orchestration. Rarely a good choice for new systems.