serverless-event-driven-and-workflow-orchestration

Serverless Event Driven And Workflow Orchestration

Use When

• Async domain workflows and integrations
• Need reliable processing under retries and spikes

Workflow

1. Define event contracts and versioning policy
2. Choose queue vs topic vs workflow engine per use case
3. Implement idempotent consumers and poison-message handling
4. Add observability for lag, age, and failure rates
5. Run chaos drills for broker outage and backlog catch-up

Required Checks

• Every consumer is idempotent
• DLQ and replay procedures are documented
• Backpressure strategy protects downstream systems
• Scheduling and ordering assumptions are explicit

Decision Framework

• Use choreography for loosely coupled domains
• Use orchestration when step visibility and recovery are critical
• Cap retry attempts with jitter and budgets
• Alert on consumer lag before user impact

Common Rationalizations And Rebuttals

• "At-least-once is good enough without idempotency." -> Duplicates will corrupt state.
• "We can process events synchronously for simplicity." -> Spikes will cascade failures.
• "DLQ review is optional." -> Poison messages will stall pipelines silently.

Evidence Pack

• Contract compatibility note
• Replay test output with duplicate events
• Lag and DLQ dashboard snapshots
• Runbook for backlog recovery

Exit Criteria

• Event pipelines are resilient under failure and replay
• Operational ownership is clear per queue/topic