Commit job acceptance and dispatch intent together
The portal returns 202 after storing a job, then loses Redis connectivity before enqueueing it. The job stays QUEUED forever with no delivery attempt.
- Focused work estimate
- 3h 30m + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Transactional outbox · Durable acceptance · Idempotency
Estimated field mix
- Distributed systems40%
- Database engineering30%
- Platform engineering30%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
Pattern topics
- Transactional OutboxApply
Commit acceptance and dispatch intent in one transaction, then demonstrate recovery after the queue is unavailable or the process stops before dispatch.
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Project context
A fictional internal document portal creates previews through a trusted mock renderer. Large batches crowd out small teams, failed documents retry forever, and operators lack a safe replay command. This exercise never executes uploaded code or real document macros.
Setup prerequisites
- Queue semantics
- Database transactions
- Operational metrics
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Commit accepted job records and durable dispatch intents atomically.
- Dispatch retries use deterministic job identities.
- A failed database transaction cannot return accepted status.
Implementation constraints
- Queue messages contain identifiers and bounded metadata, not document bytes.
Verification to include
- Lose Redis after acceptance and recover every job when dispatch resumes.
- Fail the database commit and assert neither job nor dispatch intent exists.
Deliverables
- Outbox-backed acceptance and recovery reproduction
Rollout and recovery
Drain synthetic pending intents through the new dispatcher; pause dispatch without deleting accepted work to rollback.
Value of the work
For the engineer: Practice asynchronous lifecycle control, fair scheduling, bounded retries, and artifact recovery with a deterministic provider.
For the team: See how an engineer accounts for accepted work and reduces operational toil without granting operators broad data access.
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.