[Instrumentation.AspNet] Generate metrics independently from traces (#2970)

Author: matt-hensley

opentelemetry-dotnet-contrib.sln

@@ -243,6 +243,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Shared", "Shared", "{1FCC8E
 		src\Shared\GrpcStatusCanonicalCode.cs = src\Shared\GrpcStatusCanonicalCode.cs
 		src\Shared\GrpcTagHelper.cs = src\Shared\GrpcTagHelper.cs
 		src\Shared\Guard.cs = src\Shared\Guard.cs
+		src\Shared\InstrumentationHandleManager.cs = src\Shared\InstrumentationHandleManager.cs
 		src\Shared\IServerCertificateValidationEventSource.cs = src\Shared\IServerCertificateValidationEventSource.cs
 		src\Shared\IsExternalInit.cs = src\Shared\IsExternalInit.cs
 		src\Shared\ListenerHandler.cs = src\Shared\ListenerHandler.cs

src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/.publicApi/PublicAPI.Unshipped.txt

@@ -5,11 +5,11 @@ OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.Dispose() -> void
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.Init(System.Web.HttpApplication! context) -> void
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.TelemetryHttpModule() -> void
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions
-OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnExceptionCallback.get -> System.Action<System.Diagnostics.Activity!, System.Web.HttpContext!, System.Exception!>?
+OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnExceptionCallback.get -> System.Action<System.Diagnostics.Activity?, System.Web.HttpContext!, System.Exception!>?
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnExceptionCallback.set -> void
-OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnRequestStartedCallback.get -> System.Action<System.Diagnostics.Activity!, System.Web.HttpContext!>?
+OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnRequestStartedCallback.get -> System.Action<System.Diagnostics.Activity?, System.Web.HttpContext!>?
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnRequestStartedCallback.set -> void
-OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnRequestStoppedCallback.get -> System.Action<System.Diagnostics.Activity!, System.Web.HttpContext!>?
+OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnRequestStoppedCallback.get -> System.Action<System.Diagnostics.Activity?, System.Web.HttpContext!>?
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.OnRequestStoppedCallback.set -> void
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.TextMapPropagator.get -> OpenTelemetry.Context.Propagation.TextMapPropagator!
 OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModuleOptions.TextMapPropagator.set -> void

src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/ActivityHelper.cs

@@ -60,7 +60,7 @@ public static bool HasStarted(HttpContext context, out Activity? aspNetActivity)
     /// <param name="context"><see cref="HttpContext"/>.</param>
     /// <param name="onRequestStartedCallback">Callback action.</param>
     /// <returns>New root activity.</returns>
-    public static Activity? StartAspNetActivity(TextMapPropagator textMapPropagator, HttpContext context, Action<Activity, HttpContext>? onRequestStartedCallback)
+    public static Activity? StartAspNetActivity(TextMapPropagator textMapPropagator, HttpContext context, Action<Activity?, HttpContext>? onRequestStartedCallback)
     {
         var propagationContext = textMapPropagator.Extract(default, context.Request, HttpRequestHeaderValuesGetter);
 
@@ -109,6 +109,7 @@ public static bool HasStarted(HttpContext context, out Activity? aspNetActivity)
         }
         else
         {
+            onRequestStartedCallback?.Invoke(activity, context);
             context.Items[ContextKey] = StartedButNotSampledObj;
         }
 
@@ -123,14 +124,15 @@ public static bool HasStarted(HttpContext context, out Activity? aspNetActivity)
     /// <param name="context"><see cref="HttpContext"/>.</param>
     /// <param name="onRequestStoppedCallback">Callback action.</param>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static void StopAspNetActivity(TextMapPropagator textMapPropagator, Activity? aspNetActivity, HttpContext context, Action<Activity, HttpContext>? onRequestStoppedCallback)
+    public static void StopAspNetActivity(TextMapPropagator textMapPropagator, Activity? aspNetActivity, HttpContext context, Action<Activity?, HttpContext>? onRequestStoppedCallback)
     {
         if (aspNetActivity == null)
         {
             Debug.Assert(context.Items[ContextKey] == StartedButNotSampledObj, "Context item is not StartedButNotSampledObj.");
 
             // This is the case where a start was called but no activity was
             // created due to a sampling decision.
+            onRequestStoppedCallback?.Invoke(aspNetActivity, context);
             context.Items[ContextKey] = null;
             return;
         }
@@ -178,21 +180,18 @@ public static void StopAspNetActivity(TextMapPropagator textMapPropagator, Activ
     /// <param name="exception"><see cref="Exception"/>.</param>
     /// <param name="onExceptionCallback">Callback action.</param>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static void WriteActivityException(Activity? aspNetActivity, HttpContext context, Exception exception, Action<Activity, HttpContext, Exception>? onExceptionCallback)
+    public static void WriteActivityException(Activity? aspNetActivity, HttpContext context, Exception exception, Action<Activity?, HttpContext, Exception>? onExceptionCallback)
     {
-        if (aspNetActivity != null)
+        try
         {
-            try
-            {
-                onExceptionCallback?.Invoke(aspNetActivity, context, exception);
-            }
-            catch (Exception callbackEx)
-            {
-                AspNetTelemetryEventSource.Log.CallbackException(aspNetActivity, "OnException", callbackEx);
-            }
-
-            AspNetTelemetryEventSource.Log.ActivityException(aspNetActivity, exception);
+            onExceptionCallback?.Invoke(aspNetActivity, context, exception);
+        }
+        catch (Exception callbackEx)
+        {
+            AspNetTelemetryEventSource.Log.CallbackException(aspNetActivity, "OnException", callbackEx);
         }
+
+        AspNetTelemetryEventSource.Log.ActivityException(aspNetActivity, exception);
     }
 
     /// <summary>

src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/AspNetTelemetryEventSource.cs

@@ -46,20 +46,20 @@ public void ActivityRestored(Activity activity)
     }
 
     [NonEvent]
-    public void ActivityException(Activity activity, Exception ex)
+    public void ActivityException(Activity? activity, Exception ex)
     {
         if (this.IsEnabled(EventLevel.Error, EventKeywords.All))
         {
-            this.ActivityException(activity.Id, ex.ToInvariantString());
+            this.ActivityException(activity?.Id, ex.ToInvariantString());
         }
     }
 
     [NonEvent]
-    public void CallbackException(Activity activity, string eventName, Exception ex)
+    public void CallbackException(Activity? activity, string eventName, Exception ex)
     {
         if (this.IsEnabled(EventLevel.Error, EventKeywords.All))
         {
-            this.CallbackException(activity.Id, eventName, ex.ToInvariantString());
+            this.CallbackException(activity?.Id, eventName, ex.ToInvariantString());
         }
     }
 

src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+* **Breaking Change**: Modified request lifecycle callbacks to always fire.
+  This is required as part of making ASP.NET metrics generation
+  independent from traces.
+  ([#2970](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2970))
+
 ## 1.12.0-beta.1
 
 Released 2025-May-05

src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/TelemetryHttpModuleOptions.cs

@@ -37,16 +37,16 @@ public TextMapPropagator TextMapPropagator
     /// <summary>
     /// Gets or sets a callback action to be fired when a request is started.
     /// </summary>
-    public Action<Activity, HttpContext>? OnRequestStartedCallback { get; set; }
+    public Action<Activity?, HttpContext>? OnRequestStartedCallback { get; set; }
 
     /// <summary>
     /// Gets or sets a callback action to be fired when a request is stopped.
     /// </summary>
-    public Action<Activity, HttpContext>? OnRequestStoppedCallback { get; set; }
+    public Action<Activity?, HttpContext>? OnRequestStoppedCallback { get; set; }
 
     /// <summary>
     /// Gets or sets a callback action to be fired when an unhandled
     /// exception is thrown processing a request.
     /// </summary>
-    public Action<Activity, HttpContext, Exception>? OnExceptionCallback { get; set; }
+    public Action<Activity?, HttpContext, Exception>? OnExceptionCallback { get; set; }
 }

src/OpenTelemetry.Instrumentation.AspNet/AspNetInstrumentation.cs

@@ -1,7 +1,10 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
+using System.Diagnostics.Metrics;
+using System.Reflection;
 using OpenTelemetry.Instrumentation.AspNet.Implementation;
+using OpenTelemetry.Internal;
 
 namespace OpenTelemetry.Instrumentation.AspNet;
 
@@ -10,17 +13,33 @@ namespace OpenTelemetry.Instrumentation.AspNet;
 /// </summary>
 internal sealed class AspNetInstrumentation : IDisposable
 {
+    public static readonly AspNetInstrumentation Instance = new();
+
+    public static readonly Assembly Assembly = typeof(HttpInListener).Assembly;
+    public static readonly AssemblyName AssemblyName = Assembly.GetName();
+    public static readonly string MeterName = AssemblyName.Name!;
+    public static readonly Meter Meter = new(MeterName, Assembly.GetPackageVersion());
+    public static readonly Histogram<double> HttpServerDuration = Meter.CreateHistogram(
+        "http.server.request.duration",
+        unit: "s",
+        description: "Duration of HTTP server requests.",
+        advice: new InstrumentAdvice<double> { HistogramBucketBoundaries = [0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10] });
+
+    public readonly InstrumentationHandleManager HandleManager = new();
     private readonly HttpInListener httpInListener;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="AspNetInstrumentation"/> class.
     /// </summary>
-    /// <param name="options">Configuration options for ASP.NET instrumentation.</param>
-    public AspNetInstrumentation(AspNetTraceInstrumentationOptions options)
+    private AspNetInstrumentation()
     {
-        this.httpInListener = new HttpInListener(options);
+        this.httpInListener = new();
     }
 
+    public AspNetTraceInstrumentationOptions TraceOptions { get; set; } = new();
+
+    public AspNetMetricsInstrumentationOptions MetricOptions { get; set; } = new();
+
     /// <inheritdoc/>
     public void Dispose()
     {

src/OpenTelemetry.Instrumentation.AspNet/AspNetInstrumentationMeterProviderBuilderExtensions.cs

@@ -43,9 +43,13 @@ public static MeterProviderBuilder AddAspNetInstrumentation(
             services.ConfigureOpenTelemetryMeterProvider((sp, meterProviderBuilder) =>
             {
                 var options = sp.GetRequiredService<IOptionsMonitor<AspNetMetricsInstrumentationOptions>>().Get(name: null);
+                AspNetInstrumentation.Instance.MetricOptions = options;
 
-                meterProviderBuilder.AddInstrumentation(() => new AspNetMetrics(options));
-                meterProviderBuilder.AddMeter(AspNetMetrics.InstrumentationName);
+                meterProviderBuilder.AddInstrumentation(() =>
+                {
+                    return AspNetInstrumentation.Instance.HandleManager.AddMetricHandle();
+                });
+                meterProviderBuilder.AddMeter(AspNetInstrumentation.MeterName);
             });
         });
     }

src/OpenTelemetry.Instrumentation.AspNet/AspNetInstrumentationTracerProviderBuilderExtensions.cs

@@ -46,8 +46,12 @@ public static TracerProviderBuilder AddAspNetInstrumentation(
             services.ConfigureOpenTelemetryTracerProvider((sp, tracerProviderBuilder) =>
             {
                 var options = sp.GetRequiredService<IOptionsMonitor<AspNetTraceInstrumentationOptions>>().Get(name: null);
+                AspNetInstrumentation.Instance.TraceOptions = options;
 
-                tracerProviderBuilder.AddInstrumentation(() => new AspNetInstrumentation(options));
+                tracerProviderBuilder.AddInstrumentation(() =>
+                {
+                    return AspNetInstrumentation.Instance.HandleManager.AddTracingHandle();
+                });
                 tracerProviderBuilder.AddSource(TelemetryHttpModule.AspNetSourceName);
             });
         });