# ZB.MOM.WW.Telemetry

Observability libraries for the **ZB.MOM.WW SCADA family** (OtOpcUa, MxAccessGateway, ScadaBridge). These are **libraries, not a service** — each package is linked directly into the consuming application at build time. There is no central telemetry process; instrumentation runs in-process alongside the application.

The library normalizes the three-project observability surface: a shared OpenTelemetry Resource driven by a single identity triple (`service.name` / `site.id` / `node.role`), standard instrumentation wiring, Prometheus and OTLP export, and a Serilog bootstrap with enrichers and `TraceContextEnricher` for trace↔log correlation.

**Built at 0.1.0, published to the Gitea NuGet feed, and adopted across all three apps on 2026-06-01** (branch `feat/adopt-zb-telemetry` per repo, behaviour-preserving). MxAccessGateway's MEL→Serilog migration + metrics export both landed in this pass — they were *not* actually done beforehand despite the earlier claim. ScadaBridge keeps its `LoggerConfigurationFactory` (min-level governance) and only adds the shared `TraceContextEnricher`; it does not call `AddZbSerilog`. Per-repo result + deferred follow-ons tracked in `~/Desktop/scadaproj/components/observability/GAPS.md`.

---

## Packages

| Package | Responsibilities | Key Dependencies |
|---|---|---|
| `ZB.MOM.WW.Telemetry` | `AddZbTelemetry` — wires OTel SDK (metrics + tracing), populates shared Resource (`service.name`, `service.namespace`, `service.version`, `site.id`, `node.role`, `host.name`), registers caller-supplied Meters/ActivitySources, adds standard instrumentation (ASP.NET Core, HttpClient, gRPC client, runtime, process), Prometheus always-on exporter, OTLP additive overlay. `app.MapZbMetrics()` — mounts `/metrics`. `ZbTelemetryOptions` — the single options object shared by both packages. | `Microsoft.AspNetCore.App` (framework ref), `OpenTelemetry.*` stack |
| `ZB.MOM.WW.Telemetry.Serilog` | `AddZbSerilog` — shared two-stage Serilog bootstrap: `ReadFrom.Configuration`-driven sinks, `MinimumLevel.Is(Information)` default (config-overridable), `SiteId`/`NodeRole`/`NodeHostname` enrichers from `ZbTelemetryOptions`, `TraceContextEnricher` (writes `trace_id`/`span_id` from `Activity.Current`), `ILogRedactor` seam (per-project sensitive-field redaction via `RedactionEnricher`). Does NOT freeze `Log.Logger` — safe for multi-host/test scenarios. | `ZB.MOM.WW.Telemetry`, `Serilog.*` stack |

---

## Consumer matrix

| Consumer | `ZB.MOM.WW.Telemetry` (core) | `ZB.MOM.WW.Telemetry.Serilog` |
|---|:---:|:---:|
| **OtOpcUa** | ✅ adopted | ✅ adopted (`AddZbSerilog`) |
| **MxAccessGateway** | ✅ adopted (`GatewayMetrics` exported) | ✅ adopted (MEL→Serilog migrated in this pass) |
| **ScadaBridge** | ✅ adopted (both roots) | ⚠️ referenced for `TraceContextEnricher` only — keeps `LoggerConfigurationFactory`, does **not** call `AddZbSerilog` |

All three adopted on 2026-06-01 (branch `feat/adopt-zb-telemetry` per repo). ScadaBridge's logging
deviates: it keeps its own `LoggerConfigurationFactory` (min-level governance contract) and only
adds the shared `TraceContextEnricher`. See `components/observability/GAPS.md` for the full result.

---

## Build, test, and pack commands

```bash
# From ZB.MOM.WW.Telemetry/

# Build
dotnet build ZB.MOM.WW.Telemetry.slnx
dotnet build ZB.MOM.WW.Telemetry.slnx -c Release

# Test (no external dependencies — no running OTel collector, no Serilog backend required)
dotnet test ZB.MOM.WW.Telemetry.slnx

# Pack (two .nupkg files land in artifacts/)
dotnet pack ZB.MOM.WW.Telemetry.slnx -c Release -o ./artifacts
```

All test assemblies run offline:

| Assembly | Tests |
|---|---|
| `ZB.MOM.WW.Telemetry.Tests` | 7 |
| `ZB.MOM.WW.Telemetry.Serilog.Tests` | 12 |
| **Total** | **19** |

`GeneratePackageOnBuild` is off — pack explicitly with the command above.

---

## Status

Built at **0.1.0**, published to the Gitea NuGet feed, and **adopted across all three apps on
2026-06-01** (branch `feat/adopt-zb-telemetry` per repo, behaviour-preserving). MxAccessGateway's
MEL→Serilog migration and metrics export both landed in this pass (not beforehand, despite the
earlier claim). Deferred follow-ons (MxGateway `ms`→`s` + Meter rename, ScadaBridge app instruments
+ Site-node HTTP/1.1 metrics listener, OTLP wiring) are tracked in the component backlog:

- `~/Desktop/scadaproj/components/observability/GAPS.md` — adoption status + deferred follow-ons

Design documentation:

- `~/Desktop/scadaproj/components/observability/spec/SPEC.md` — normalized observability target
- `~/Desktop/scadaproj/components/observability/spec/METRIC-CONVENTIONS.md` — metric naming reference
- `~/Desktop/scadaproj/components/observability/shared-contract/ZB.MOM.WW.Telemetry.md` — proposed shared-library API
- `~/Desktop/scadaproj/components/observability/current-state/` — per-project current state (code-verified)