[Instrumentation.EntityFrameworkCore] Database metrics

src/OpenTelemetry.Instrumentation.EntityFrameworkCore/.publicApi/PublicAPI.Unshipped.txt

@@ -8,7 +8,9 @@ OpenTelemetry.Instrumentation.EntityFrameworkCore.EntityFrameworkInstrumentation
 OpenTelemetry.Instrumentation.EntityFrameworkCore.EntityFrameworkInstrumentationOptions.SetDbStatementForText.set -> void
 OpenTelemetry.Instrumentation.EntityFrameworkCore.EntityFrameworkInstrumentationOptions.EnrichWithIDbCommand.get -> System.Action<System.Diagnostics.Activity!, System.Data.IDbCommand!>?
 OpenTelemetry.Instrumentation.EntityFrameworkCore.EntityFrameworkInstrumentationOptions.EnrichWithIDbCommand.set -> void
+OpenTelemetry.Metrics.EntityFrameworkCoreMeterProviderBuilderExtensions
 OpenTelemetry.Trace.TracerProviderBuilderExtensions
+static OpenTelemetry.Metrics.EntityFrameworkCoreMeterProviderBuilderExtensions.AddEntityFrameworkCoreInstrumentation(this OpenTelemetry.Metrics.MeterProviderBuilder! builder) -> OpenTelemetry.Metrics.MeterProviderBuilder!
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddEntityFrameworkCoreInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder) -> OpenTelemetry.Trace.TracerProviderBuilder!
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddEntityFrameworkCoreInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder, string? name, System.Action<OpenTelemetry.Instrumentation.EntityFrameworkCore.EntityFrameworkInstrumentationOptions!>? configure) -> OpenTelemetry.Trace.TracerProviderBuilder!
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddEntityFrameworkCoreInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder, System.Action<OpenTelemetry.Instrumentation.EntityFrameworkCore.EntityFrameworkInstrumentationOptions!>? configure) -> OpenTelemetry.Trace.TracerProviderBuilder!

src/OpenTelemetry.Instrumentation.EntityFrameworkCore/EntityFrameworkCoreMeterProviderBuilderExtensions.cs

@@ -0,0 +1,39 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#if NET
+using System.Diagnostics.CodeAnalysis;
+#endif
+using OpenTelemetry.Instrumentation.EntityFrameworkCore;
+using OpenTelemetry.Instrumentation.EntityFrameworkCore.Implementation;
+using OpenTelemetry.Internal;
+
+namespace OpenTelemetry.Metrics;
+
+/// <summary>
+/// Extension methods to simplify registering of dependency instrumentation.
+/// </summary>
+public static class EntityFrameworkCoreMeterProviderBuilderExtensions
+{
+    /// <summary>
+    /// Enables EntityFrameworkCore instrumentation.
+    /// </summary>
+    /// <param name="builder"><see cref="MeterProviderBuilder"/> being configured.</param>
+    /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
+#if NET
+    // TODO [RequiresUnreferencedCode(SqlClientInstrumentation.SqlClientTrimmingUnsupportedMessage)]
+#endif
+    public static MeterProviderBuilder AddEntityFrameworkCoreInstrumentation(this MeterProviderBuilder builder)
+    {
+        Guard.ThrowIfNull(builder);
+
+        builder.AddInstrumentation(sp =>
+        {
+            return EntityFrameworkInstrumentation.AddMetricHandle();
+        });
+
+        builder.AddMeter(EntityFrameworkDiagnosticListener.MeterName);
+
+        return builder;
+    }
+}

src/OpenTelemetry.Instrumentation.EntityFrameworkCore/EntityFrameworkInstrumentation.cs

@@ -7,20 +7,68 @@ namespace OpenTelemetry.Instrumentation.EntityFrameworkCore;
 
 internal class EntityFrameworkInstrumentation : IDisposable
 {
+    public static readonly EntityFrameworkInstrumentation Instance = new();
+    internal static int MetricHandles;
+    internal static int TracingHandles;
+
     private readonly DiagnosticSourceSubscriber diagnosticSourceSubscriber;
 
-    public EntityFrameworkInstrumentation(EntityFrameworkInstrumentationOptions? options)
+    public EntityFrameworkInstrumentation()
     {
         this.diagnosticSourceSubscriber = new DiagnosticSourceSubscriber(
-            name => new EntityFrameworkDiagnosticListener(name, options),
+            name => new EntityFrameworkDiagnosticListener(name),
             listener => listener.Name == EntityFrameworkDiagnosticListener.DiagnosticSourceName,
             null,
             EntityFrameworkInstrumentationEventSource.Log.UnknownErrorProcessingEvent);
         this.diagnosticSourceSubscriber.Subscribe();
     }
 
+    public static EntityFrameworkInstrumentationOptions TracingOptions { get; set; } = new();
+
+    public static IDisposable AddMetricHandle() => new MetricHandle();
+
+    public static IDisposable AddTracingHandle() => new TracingHandle();
+
     public void Dispose()
     {
         this.diagnosticSourceSubscriber?.Dispose();
     }
+
+    private sealed class MetricHandle : IDisposable
+    {
+        private bool disposed;
+
+        public MetricHandle()
+        {
+            Interlocked.Increment(ref MetricHandles);
+        }
+
+        public void Dispose()
+        {
+            if (!this.disposed)
+            {
+                Interlocked.Decrement(ref MetricHandles);
+                this.disposed = true;
+            }
+        }
+    }
+
+    private sealed class TracingHandle : IDisposable
+    {
+        private bool disposed;
+
+        public TracingHandle()
+        {
+            Interlocked.Increment(ref TracingHandles);
+        }
+
+        public void Dispose()
+        {
+            if (!this.disposed)
+            {
+                Interlocked.Decrement(ref TracingHandles);
+                this.disposed = true;
+            }
+        }
+    }
 }