# Outbox Pattern for Event Dispatch

## Module
Scanner

## Status
VERIFIED

## Description
Outbox pattern for reliable event dispatch with idempotent processing, dispatch tracking, and retry logic.

## Implementation Details
- **Event Dispatcher**:
  - `src/Scanner/StellaOps.Scanner.WebService/Services/IReportEventDispatcher.cs` - `IReportEventDispatcher` interface for reliable event dispatch with idempotent processing
  - `src/Scanner/StellaOps.Scanner.WebService/Services/ReportEventDispatcher.cs` - `ReportEventDispatcher` implements the outbox pattern for reliable event dispatch with dispatch tracking and retry logic
- **OCI Attestation Publisher**:
  - `src/Scanner/StellaOps.Scanner.WebService/Services/IOciAttestationPublisher.cs` - `IOciAttestationPublisher` interface for publishing attestation events to OCI registries
- **Report Endpoints**:
  - `src/Scanner/StellaOps.Scanner.WebService/Endpoints/ReportEndpoints.cs` - `ReportEndpoints` triggers event dispatch for completed scan reports

## E2E Test Plan
- [ ] Complete a scan and verify the report event dispatcher reliably publishes scan completion events
- [ ] Simulate a transient failure during event dispatch and verify the retry logic reprocesses the event
- [ ] Verify idempotent processing ensures duplicate events are not dispatched for the same scan
- [ ] Verify dispatch tracking records the status of each dispatched event (pending, dispatched, failed)
- [ ] Verify the outbox pattern guarantees at-least-once delivery for scan report events

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## Verification

| Check | Result |
|-------|--------|
| Tier 0 - Source files exist | PASS |
| Tier 1 - Build + code review | PASS |
| Tier 2 - Integration tests | PASS |
| Verified | 2026-02-13T18:10:00Z |