[Instrumentation.AspNet] Add metric enrich functionality

src/OpenTelemetry.Instrumentation.AspNet/.publicApi/net462/PublicAPI.Unshipped.txt

@@ -1,13 +1,19 @@
-OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions
+OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.AspNetInstrumentationOptions() -> void
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.Enrich.get -> System.Action<System.Diagnostics.Activity!, string!, object!>?
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.Enrich.set -> void
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.Filter.get -> System.Func<System.Web.HttpContext!, bool>?
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.Filter.set -> void
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.RecordException.get -> bool
 OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions.RecordException.set -> void
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.AspNetMetricsInstrumentationOptions() -> void
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.Enrich.get -> OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.EnrichFunc?
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.Enrich.set -> void
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.EnrichFunc
 OpenTelemetry.Metrics.MeterProviderBuilderExtensions
 OpenTelemetry.Trace.TracerProviderBuilderExtensions
 static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.AddAspNetInstrumentation(this OpenTelemetry.Metrics.MeterProviderBuilder! builder) -> OpenTelemetry.Metrics.MeterProviderBuilder!
+static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.AddAspNetInstrumentation(this OpenTelemetry.Metrics.MeterProviderBuilder! builder, System.Action<OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions!>? configure) -> OpenTelemetry.Metrics.MeterProviderBuilder!
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddAspNetInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder) -> OpenTelemetry.Trace.TracerProviderBuilder!
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddAspNetInstrumentation(this OpenTelemetry.Trace.TracerProviderBuilder! builder, System.Action<OpenTelemetry.Instrumentation.AspNet.AspNetInstrumentationOptions!>? configure) -> OpenTelemetry.Trace.TracerProviderBuilder!

src/OpenTelemetry.Instrumentation.AspNet/AspNetMetrics.cs

@@ -37,10 +37,11 @@ internal sealed class AspNetMetrics : IDisposable
     /// <summary>
     /// Initializes a new instance of the <see cref="AspNetMetrics"/> class.
     /// </summary>
-    public AspNetMetrics()
+    /// <param name="options">The metrics configuration options.</param>
+    public AspNetMetrics(AspNetMetricsInstrumentationOptions options)
     {
         this.meter = new Meter(InstrumentationName, InstrumentationVersion);
-        this.httpInMetricsListener = new HttpInMetricsListener(this.meter);
+        this.httpInMetricsListener = new HttpInMetricsListener(this.meter, options);
     }
 
     /// <inheritdoc/>

src/OpenTelemetry.Instrumentation.AspNet/AspNetMetricsInstrumentationOptions.cs

@@ -0,0 +1,38 @@
+// <copyright file="AspNetMetricsInstrumentationOptions.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Diagnostics;
+using System.Web;
+
+namespace OpenTelemetry.Instrumentation.AspNet;
+
+/// <summary>
+/// Options for metric instrumentation.
+/// </summary>
+public sealed class AspNetMetricsInstrumentationOptions
+{
+    /// <summary>
+    /// Delegate for enrichment of recorded metric with additional tags.
+    /// </summary>
+    /// <param name="context"><see cref="HttpContext"/>: the HttpContext object. Both Request and Response are available.</param>
+    /// <param name="tags"><see cref="TagList"/>: List of current tags. You can add additional tags to this list. </param>
+    public delegate void EnrichFunc(HttpContext context, ref TagList tags);
+
+    /// <summary>
+    /// Gets or sets an function to enrich a recorded metric with additional custom tags.
+    /// </summary>
+    public EnrichFunc? Enrich { get; set; }
+}

src/OpenTelemetry.Instrumentation.AspNet/CHANGELOG.md

@@ -2,6 +2,12 @@
 
 ## Unreleased
 
+* Added enrich functionality to metric instrumentation
+  ([#1407](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/1407)).
+
+  * New overload of `AddAspNetInstrumentation` now accepts a configuration delegate.
+  * The `Enrich` can be used to add additional metric attributes.
+
 ## 1.6.0-beta.2
 
 Released 2023-Nov-06

src/OpenTelemetry.Instrumentation.AspNet/Implementation/HttpInMetricsListener.cs

@@ -25,11 +25,13 @@ namespace OpenTelemetry.Instrumentation.AspNet.Implementation;
 internal sealed class HttpInMetricsListener : IDisposable
 {
     private readonly Histogram<double> httpServerDuration;
+    private readonly AspNetMetricsInstrumentationOptions options;
 
-    public HttpInMetricsListener(Meter meter)
+    public HttpInMetricsListener(Meter meter, AspNetMetricsInstrumentationOptions options)
     {
         this.httpServerDuration = meter.CreateHistogram<double>("http.server.duration", "ms", "Measures the duration of inbound HTTP requests.");
         TelemetryHttpModule.Options.OnRequestStoppedCallback += this.OnStopActivity;
+        this.options = options;
     }
 
     public void Dispose()
@@ -48,6 +50,18 @@ private void OnStopActivity(Activity activity, HttpContext context)
             { SemanticConventions.AttributeHttpStatusCode, context.Response.StatusCode },
         };
 
+        if (this.options.Enrich is not null)
+        {
+            try
+            {
+                this.options.Enrich(context, ref tags);
+            }
+            catch (Exception ex)
+            {
+                AspNetInstrumentationEventSource.Log.EnrichmentException(nameof(HttpInMetricsListener), ex);
+            }
+        }
+
         this.httpServerDuration.Record(activity.Duration.TotalMilliseconds, tags);
     }
 }

src/OpenTelemetry.Instrumentation.AspNet/MeterProviderBuilderExtensions.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Instrumentation.AspNet;
 using OpenTelemetry.Internal;
 
@@ -29,12 +30,25 @@ public static class MeterProviderBuilderExtensions
     /// </summary>
     /// <param name="builder"><see cref="MeterProviderBuilder"/> being configured.</param>
     /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
+    public static MeterProviderBuilder AddAspNetInstrumentation(this MeterProviderBuilder builder) =>
+        AddAspNetInstrumentation(builder, configure: null);
+
+    /// <summary>
+    /// Enables the incoming requests automatic data collection for ASP.NET.
+    /// </summary>
+    /// <param name="builder"><see cref="MeterProviderBuilder"/> being configured.</param>
+    /// <param name="configure">Callback action for configuring <see cref="AspNetMetricsInstrumentationOptions"/>.</param>
+    /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
     public static MeterProviderBuilder AddAspNetInstrumentation(
-        this MeterProviderBuilder builder)
+        this MeterProviderBuilder builder,
+        Action<AspNetMetricsInstrumentationOptions>? configure)
     {
         Guard.ThrowIfNull(builder);
 
+        var options = new AspNetMetricsInstrumentationOptions();
+        configure?.Invoke(options);
+
         builder.AddMeter(AspNetMetrics.InstrumentationName);
-        return builder.AddInstrumentation(() => new AspNetMetrics());
+        return builder.AddInstrumentation(() => new AspNetMetrics(options));
     }
 }

src/OpenTelemetry.Instrumentation.AspNet/README.md

@@ -128,13 +128,13 @@ Currently, the instrumentation supports the following metric.
 |-------|-----------------|------|-------------|
 | `http.server.duration` | Histogram | `ms` | Measures the duration of inbound HTTP requests. |
 
-## Advanced configuration
+## Advanced trace configuration
 
 This instrumentation can be configured to change the default behavior by using
 `AspNetInstrumentationOptions`, which allows configuring `Filter` as explained
 below.
 
-### Filter
+### Trace Filter
 
 This instrumentation by default collects all the incoming http requests. It
 allows filtering of requests by using the `Filter` function in
@@ -162,7 +162,7 @@ instrumentation. OpenTelemetry has a concept of a
 [Sampler](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/sdk.md#sampling),
 and the `Filter` option does the filtering *before* the Sampler is invoked.
 
-### Enrich
+### Trace Enrich
 
 This option allows one to enrich the activity with additional information from
 the raw `HttpRequest`, `HttpResponse` objects. The `Enrich` action is called
@@ -208,6 +208,32 @@ This instrumentation automatically sets Activity Status to Error if an unhandled
 exception is thrown. Additionally, `RecordException` feature may be turned on,
 to store the exception to the Activity itself as ActivityEvent.
 
+## Advanced metric configuration
+
+This instrumentation can be configured to change the default behavior by using
+`AspNetMetricsInstrumentationOptions` as explained below.
+
+### Metric Enrich
+
+This option allows one to enrich the metric with additional information from
+the `HttpContext`. The `Enrich` action is always called unless the metric was
+filtered. The callback allows for modifying the tag list. If the callback
+throws an exception the metric will still be recorded.
+
+```csharp
+this.meterProvider = Sdk.CreateMeterProviderBuilder()
+    .AddAspNetInstrumentation(options => options.Enrich =
+        (HttpContext context, ref TagList tags) =>
+    {
+        // Add request content type to the metric tags.
+        if (!string.IsNullOrEmpty(context.Request.ContentType))
+        {
+            tags.Add("custom.content.type", context.Request.ContentType);
+        }
+    })
+    .Build();
+```
+
 ## References
 
 * [ASP.NET](https://dotnet.microsoft.com/apps/aspnet)

test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInListenerTests.cs

@@ -58,49 +58,7 @@ public class HttpInListenerTests
         string? filter = null,
         bool recordException = false)
     {
-        RouteData routeData;
-        switch (routeType)
-        {
-            case 0: // WebForm, no route data.
-                routeData = new RouteData();
-                break;
-            case 1: // Traditional MVC.
-            case 2: // Attribute routing MVC.
-            case 3: // Traditional WebAPI.
-                routeData = new RouteData()
-                {
-                    Route = new Route(routeTemplate, null),
-                };
-                break;
-            case 4: // Attribute routing WebAPI.
-                routeData = new RouteData();
-                var value = new[]
-                {
-                    new
-                    {
-                        Route = new
-                        {
-                            RouteTemplate = routeTemplate,
-                        },
-                    },
-                };
-                routeData.Values.Add(
-                    "MS_SubRoutes",
-                    value);
-                break;
-            default:
-                throw new NotSupportedException();
-        }
-
-        HttpContext.Current = new HttpContext(
-            new HttpRequest(string.Empty, url, string.Empty)
-            {
-                RequestContext = new RequestContext()
-                {
-                    RouteData = routeData,
-                },
-            },
-            new HttpResponse(new StringWriter()));
+        HttpContext.Current = RouteTestHelper.BuildHttpContext(url, routeType, routeTemplate);
 
         typeof(HttpRequest).GetField("_wr", BindingFlags.Instance | BindingFlags.NonPublic).SetValue(HttpContext.Current.Request, Mock.Of<HttpWorkerRequest>());