Design the transactional dispatch contract for extraction work
An accepted upload can be stranded if the API commits metadata and crashes before calling the processing provider.
- Focused work estimate
- 4h + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Transactional outbox · Recovery
Estimated field mix
- System design40%
- Distributed systems40%
- Database engineering20%
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 procurement portal extracts metadata from uploaded documents. Product wants a responsive upload flow; security wants parser failures isolated from customer-facing processes.
Setup prerequisites
- Create synthetic upload metadata and a fake processing provider.
- Treat diagrams as proposals; implement only local contract probes.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- ABOUND-101 · Translate document-processing expectations into a bounded workload model
- ABOUND-102 · Draw the document trust boundary with authoritative state owners
- ABOUND-103 · Write the decision record for direct-to-storage document upload
- ABOUND-104 · Specify a document lifecycle that survives parser retries
Acceptance criteria
- Commit upload acceptance and an outbox fact together.
- Derive a deterministic dispatch identity from the accepted generation.
- Specify claim, retry and duplicate-delivery behavior.
Implementation constraints
- Use PostgreSQL plus a local provider fake, without adding a broker topology.
Verification to include
- Crash after transaction commit and recover dispatch from the outbox.
- Repeat provider delivery and prove one accepted completion.
Deliverables
- Outbox contract and interruption probe
Rollout and recovery
Prototype on synthetic uploads; halt new acceptance if durable dispatch cannot be recorded.
Value of the work
For the engineer: Practice boundary decisions backed by executable consistency and failure checks.
For the team: Review architecture tradeoffs with explicit assumptions before infrastructure commitment.
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.