Validate carrier events without discarding a whole batch
A 200-event batch contains one scan with an empty parcel reference. The importer rejects all 200, leaving valid deliveries invisible until the next carrier export.
- Focused work estimate
- 2h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Schema validation · Batch processing · Error reporting
Estimated field mix
- Data engineering80%
- API design20%
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 delivery marketplace receives JSON batches from three carriers. One uses local timestamps, another retries whole batches, and a third corrects delivery scans. Customer support needs a stable timeline rather than the last payload received.
Setup prerequisites
- JSON schema validation
- SQL queries
- Event-time concepts
Preceding work
No earlier ticket is required. Complete the project setup above.
Acceptance criteria
- Classify each row as accepted or rejected with a source position.
- Require carrier event ID, parcel reference, event code, and timestamp.
- Accepted and rejected counts sum to the received count.
Implementation constraints
- Publish the partial-acceptance contract; never silently drop malformed rows.
Verification to include
- Process 199 valid rows and one malformed row with exact counts.
- Reject oversized batches and invalid JSON without accepted events.
Deliverables
- Batch validation contract and mixed-validity fixtures
Rollout and recovery
Enable partial acceptance for one synthetic carrier; retain rejection reports if the route is disabled.
Value of the work
For the engineer: Practice ingestion contracts, deduplication, event-time reconciliation, and replayable data repair.
For the team: Examine how an engineer preserves source lineage and handles bad partner data without losing valid business events.
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.