Dispatch each check through a durable deterministic attempt identity
The coordinator crashes after dispatching one checker and cannot tell which of the three still needs to start.
- Focused work estimate
- 4h + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Outbox · Idempotency
Estimated field mix
- Distributed systems60%
- Database engineering40%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional vendor portal runs format, policy and duplicate checks in parallel. A slow checker blocks completion, while duplicate callbacks can produce contradictory final summaries.
Setup prerequisites
- Create synthetic document identities and three fake check providers.
- No real risk scoring, hiring decisions or candidate execution is included.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Persist check-attempt identity and outbox dispatch per required checker.
- Keep dispatch retries bound to the same input and checker version.
- Reject contradictory reuse of an attempt identity.
Implementation constraints
- Call providers outside the database transaction.
Verification to include
- Crash after one dispatched check and resume remaining work.
- Replay an outbox fact and keep one logical provider attempt.
Deliverables
- Check dispatch transaction and crash probe
Rollout and recovery
Prototype with fake providers; stop new runs if attempt identity cannot be persisted.
Value of the work
For the engineer: Practice fan-out/fan-in, deadline policies and immutable aggregation.
For the team: Review trustworthy partial-result handling and controllable parallel work.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.