Replay accepted deliveries with processing receipts

Make a new processing run explicit while keeping transport deduplication intact.

Type: Build Languages: Go Stage: 4 of 4 Prerequisites: Basic functions, collections, JSON and the previous stages when applicable. Time: ~2 hours

What you build

Replay reads only accepted inbox entries. The authored local processor extracts eventId and data from JSON and writes a processing receipt keyed by delivery ID plus explicit run ID. Repeating the same run returns its existing receipt; a different run is a deliberate replay.

Worked example

Delivery delivery-1 carries business-42. Replay run review-1 creates one receipt; repeating review-1 creates none. A new delivery-2 may carry business-42 and is a distinct transport identity. Business-level deduplication is a downstream policy.

Implement the contract

Replay(dir,id,run,now)(Processing,created,error); fields schemaVersion, deliveryId, runId, businessEventId, bodySHA256, processedAt and payload. CLI modes demo, serve, sign, inspect and replay compose the contracts. The processor writes a local artifact and does not call an external side-effecting service.

Reject malformed input before producing a partial artifact. The tests include held-out records separate from the demonstration fixture.

Run your work

python3 scripts/project_test.py signed-webhook-inbox --init /tmp/signed-webhook-inbox-work
python3 scripts/project_test.py signed-webhook-inbox --stage 4 --path /tmp/signed-webhook-inbox-work --strict

Initialization copies cumulative scaffolding without replacing your work. Implement the TODO functions in the first-stage starter; later-stage starter notes describe the new behavior. Tests import the learner workspace. Run the command in the README against your own input after passing the stage.

Inspect and extend

Feed receipt.payload to a downstream queue with an idempotency key. External exactly-once effects require a separate transactional design; a local processing receipt cannot establish that guarantee.

Go standard library and Node standard library. All fixtures and implementations are original.