# Observability

Source of truth: `src/Program.cs` (no dedicated logging config files exist in repo).

## Health check

```csharp
app.MapGet("/health", () => Results.Ok(new { status = "healthy" }));
```

- Path: `GET /health`
- Auth: none (`MapGet` bypasses controller-level `[Authorize]`).
- Response: `200 { "status": "healthy" }`
- **Liveness only**: this endpoint does not probe the DB, RabbitMQ, or filesystem. A pod can return healthy while the failsafe outbox is unable to publish or while DB connectivity is broken.

## API documentation

- `app.UseSwagger()` and `app.UseSwaggerUI()` mounted unconditionally (ADR-005).
- Endpoints: `/swagger/v1/swagger.json` (OpenAPI), `/swagger/index.html` (UI).
- No version pinning of the OpenAPI document (Swashbuckle defaults).

## Logging

- Default ASP.NET Core console logger. No `appsettings.json` overrides in repo.
- No structured logger (Serilog / NLog) configured.
- No correlation id middleware in repo (`X-Request-Id` not propagated).

## Metrics

None configured today. Possible additions:
- `prometheus-net` exporter on `/metrics`.
- ASP.NET Core `MetricsCollector` (built-in HTTP / runtime counters).

## Traces

None configured. OpenTelemetry SDK is not referenced in `csproj`.

## Image revision stamp

The runtime container has `AZAION_REVISION = $CI_COMMIT_SHA` set as an env var (Dockerfile + Woodpecker pipeline). This makes "what's running?" diagnosable from inside the container with `printenv AZAION_REVISION` or by surfacing it in a future `/info` endpoint.

## Error visibility to clients

`ErrorHandlingMiddleware` maps exceptions to JSON `{ statusCode, message }` with HTTP 400 / 404 / 409 / 500. Internal exception details are not leaked beyond the `message` string (confirm during Step 4 verification — make sure 500 paths do not echo stack traces).

## Open observability items

- **Readiness vs liveness split**: today there is one endpoint that does not check dependencies. A `GET /ready` that pings DB and (optionally) RabbitMQ would unblock proper rolling-update gates.
- **Structured logs** with request id correlation across HTTP + outbox drain + SSE.
- **Outbox depth metric** (`COUNT(*)` on `annotations_queue_records`) — surfaces stuck-failsafe scenarios early.
- **SSE subscriber count metric** — visibility into connected UIs.
- **Stream publish lag** — time from outbox row insertion to RabbitMQ publish.
- **Failure injection / chaos hooks** — none today.

These are candidates for the deploy-and-retro phase of autodev (Steps 14–17 once the project enters Phase B).