Lab: build a resilient ticket adapter

Assignment

Implement a fake ticket system with delayed responses, duplicate webhook events, out-of-order versions, and a write that commits before timing out.

Build sequence

1. Define read and update contracts with actor, record version, and operation ID.
2. Handle duplicate and stale events without regressing local state.
3. Bound retries and respect a simulated rate-limit response.
4. Reconcile the ambiguous write outcome before retrying.

Acceptance checks

• Event replay does not duplicate effects.
• Local state never moves backward to an older version.
• The operator can distinguish a denied request from an unavailable service.

Evidence to keep

Submit the working artifact or decision document described above, the inputs used, and the observed results for every acceptance check. Include one failed attempt and the change you made after investigating it. Label fixture-based outcomes separately from live-system measurements. These artifacts become part of your final portfolio review.