feat(scadabridge): wire AddZbTelemetry + /metrics in both composition roots

src/ZB.MOM.WW.ScadaBridge.Host/Program.cs

@@ -21,6 +21,7 @@ using ZB.MOM.WW.ScadaBridge.Security;
 using ZB.MOM.WW.ScadaBridge.SiteCallAudit;
 using ZB.MOM.WW.ScadaBridge.TemplateEngine;
 using ZB.MOM.WW.ScadaBridge.Transport;
+using ZB.MOM.WW.Telemetry;
 using Serilog;
 
 // SCADABRIDGE_CONFIG determines which role-specific config to load (Central or Site)
@@ -248,6 +249,12 @@ try
         // All three are anonymous and use the canonical ZbHealthWriter JSON output.
         app.MapZbHealth();
 
+        // Observability — mount the always-on Prometheus /metrics scrape endpoint.
+        // AddZbTelemetry (in SiteServiceRegistration.BindSharedOptions) wires the OTel
+        // Resource + standard instrumentation + Prometheus exporter; this exposes them.
+        // Requires endpoint routing (app.UseRouting() above).
+        app.MapZbMetrics();
+
         app.MapStaticAssets();
         app.MapCentralUI<ZB.MOM.WW.ScadaBridge.Host.Components.App>();
         app.MapInboundAPI();
@@ -304,6 +311,17 @@ try
 
         var app = builder.Build();
 
+        // Endpoint routing middleware. The gRPC service mapping below and the
+        // /metrics scrape endpoint both run on endpoint routing, so UseRouting()
+        // must be present before the Map* calls on the site role.
+        app.UseRouting();
+
+        // Observability — mount the always-on Prometheus /metrics scrape endpoint.
+        // AddZbTelemetry (in SiteServiceRegistration.Configure → BindSharedOptions)
+        // wires the OTel Resource + standard instrumentation + Prometheus exporter;
+        // this exposes them on the site node too.
+        app.MapZbMetrics();
+
         // Map gRPC service — resolves the singleton SiteStreamGrpcServer from DI
         app.MapGrpcService<ZB.MOM.WW.ScadaBridge.Communication.Grpc.SiteStreamGrpcServer>();
 

src/ZB.MOM.WW.ScadaBridge.Host/SiteServiceRegistration.cs

@@ -11,6 +11,7 @@ using ZB.MOM.WW.ScadaBridge.NotificationService;
 using ZB.MOM.WW.ScadaBridge.SiteEventLogging;
 using ZB.MOM.WW.ScadaBridge.SiteRuntime;
 using ZB.MOM.WW.ScadaBridge.StoreAndForward;
+using ZB.MOM.WW.Telemetry;
 
 namespace ZB.MOM.WW.ScadaBridge.Host;
 
@@ -114,5 +115,19 @@ public static class SiteServiceRegistration
         // writers so they can stamp the SourceNode column. Registered here in
         // shared bootstrap because every node (central + site) needs it.
         services.AddSingleton<INodeIdentityProvider, NodeIdentityProvider>();
+
+        // Observability — shared ZB.MOM.WW.Telemetry. Registered in shared bootstrap so
+        // BOTH the central and site composition roots wire the OTel Resource (the
+        // service.name/site.id/node.role identity triple) + standard instrumentation +
+        // the always-on Prometheus exporter. Mount the /metrics scrape endpoint per role
+        // with app.MapZbMetrics(). The same `?? "central"` SiteId default Program.cs uses
+        // is applied here so the Resource attribute matches the log-enricher value.
+        // Meters left empty — application instruments are a deferred follow-on.
+        services.AddZbTelemetry(o =>
+        {
+            o.ServiceName = "scadabridge";
+            o.SiteId = config["ScadaBridge:Node:SiteId"] ?? "central";
+            o.NodeRole = config["ScadaBridge:Node:Role"];
+        });
     }
 }