workflow-orchestration-patterns

The saga pattern manages distributed transactions by defining compensation logic for each step, ensuring eventual consistency. You structure workflows to execute forward and compensate backward automatically upon failures, maintaining reliable state across microservices.

Durable workflows persist their execution state automatically, allowing them to resume from the exact point of failure after an infrastructure crash. You separate business logic into workflows and side-effect tasks into activities to guarantee deterministic replay.

State management for long-running processes is handled by modeling them as entity workflows. This approach encapsulates state and behavior within a long-lived workflow, processing event-driven updates while maintaining durability and consistency.

Fan-out fan-in parallel execution dispatches multiple activity tasks concurrently from a workflow and aggregates their results upon completion. This pattern maximizes throughput for independent operations while the orchestration engine handles retries and state persistence.

Workflow determinism constraints require that workflow code produces the exact same sequence of commands upon replay. You must isolate non-deterministic operations like API calls or database access into activities, keeping the workflow logic purely functional.

Workflow orchestration is needed for distributed systems when processes are long-running, require multi-step transactions, or demand guaranteed completion despite failures. It replaces standard API calls with durable execution, saga rollbacks, and automatic state recovery.