Workflow Coordination and Sagas

Workflow coordination is where event-driven systems move beyond distributing facts and start managing business processes that span time, teams, and failure points. At that point, the architecture needs a clear answer to where the process logic lives, how progress is tracked, and what happens when one step succeeds but a later step fails.

Read the lessons in order. The first covers choreography, where services react to events without a central coordinator. The second turns to orchestration, where one controller makes the workflow explicit. The third explains sagas as long-running distributed business processes built from local transactions. The fourth focuses on compensation design, which is where many workflow models fail because rollback in business systems is rarely literal undo.

If your platform has many events flowing between services but nobody can clearly describe where one business process starts, who owns its state, or how failure is corrected, Chapter 11 is where that workflow model needs to become explicit.

In this section

• Choreography
  A practical lesson on choreographed workflows, including where distributed reaction models work well and where they become hard to trace and govern.
• Orchestration
  A practical lesson on orchestrated workflows, including explicit process control, coordinator state, and the trade-off between visibility and centralization.
• Sagas
  A practical lesson on sagas as long-running distributed business processes built from local transactions plus coordinated recovery paths.
• Compensation Design
  A practical lesson on compensation as business correction logic, including reversible versus irreversible effects, timing choices, and common compensation mistakes.