Refactor code structure for improved readability and maintainability; optimize performance in key functions.

src/Gateway/StellaOps.Gateway.WebService/Services/GatewayMetrics.cs

@@ -0,0 +1,38 @@
+using System.Diagnostics.Metrics;
+using System.Linq;
+using StellaOps.Router.Common.Abstractions;
+
+namespace StellaOps.Gateway.WebService.Services;
+
+public sealed class GatewayMetrics
+{
+    public const string MeterName = "StellaOps.Gateway.WebService";
+
+    private static readonly Meter Meter = new(MeterName, "1.0.0");
+    private readonly IGlobalRoutingState _routingState;
+
+    public GatewayMetrics(IGlobalRoutingState routingState)
+    {
+        _routingState = routingState;
+
+        Meter.CreateObservableGauge(
+            "gateway_active_connections",
+            () => GetActiveConnections(),
+            description: "Number of active microservice connections.");
+
+        Meter.CreateObservableGauge(
+            "gateway_registered_endpoints",
+            () => GetRegisteredEndpoints(),
+            description: "Number of registered endpoints across all connections.");
+    }
+
+    public long GetActiveConnections()
+    {
+        return _routingState.GetAllConnections().Count;
+    }
+
+    public long GetRegisteredEndpoints()
+    {
+        return _routingState.GetAllConnections().Sum(c => c.Endpoints.Count);
+    }
+}