[Instrumentation.AspNet] Add Filter Support For ASP.NET Instrumented Metrics

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

@@ -11,6 +11,8 @@ OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.AspNetM
 OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.Enrich.get -> OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.EnrichFunc?
 OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.Enrich.set -> void
 OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.EnrichFunc
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.Filter.get -> System.Func<System.Web.HttpContext!, bool>?
+OpenTelemetry.Instrumentation.AspNet.AspNetMetricsInstrumentationOptions.Filter.set -> void
 OpenTelemetry.Metrics.MeterProviderBuilderExtensions
 OpenTelemetry.Trace.TracerProviderBuilderExtensions
 static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.AddAspNetInstrumentation(this OpenTelemetry.Metrics.MeterProviderBuilder! builder) -> OpenTelemetry.Metrics.MeterProviderBuilder!

src/OpenTelemetry.Instrumentation.AspNet/AspNetMetricsInstrumentationOptions.cs

@@ -1,38 +1,54 @@
-// <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; }
-}
+// <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;
+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; }
+
+    /// <summary>
+    /// Gets or sets a filter function that determines whether or not to
+    /// collect telemetry on a per request basis.
+    /// </summary>
+    /// <remarks>
+    /// <item>The return value for the filter function is interpreted as:
+    /// <list type="bullet">
+    /// <item>If filter returns <see langword="true" />, the request is
+    /// collected.</item>
+    /// <item>If filter returns <see langword="false" /> or throws an
+    /// exception the request is NOT collected.</item>
+    /// </list></item>
+    /// </remarks>
+    public Func<HttpContext, bool>? Filter { get; set; }
+}

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

@@ -41,6 +41,20 @@ public void Dispose()
 
     private void OnStopActivity(Activity activity, HttpContext context)
     {
+        try
+        {
+            if (this.options.Filter?.Invoke(context) == false && Activity.Current != null)
+            {
+                AspNetInstrumentationEventSource.Log.RequestIsFilteredOut(Activity.Current.OperationName);
+                return;
+            }
+        }
+        catch (Exception ex)
+        {
+            AspNetInstrumentationEventSource.Log.RequestFilterException(nameof(HttpInMetricsListener), ex);
+            return;
+        }
+
         // TODO: This is just a minimal set of attributes. See the spec for additional attributes:
         // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/http-metrics.md#http-server
         var tags = new TagList

src/OpenTelemetry.Instrumentation.AspNet/MeterProviderBuilderExtensions.cs

@@ -31,8 +31,8 @@ public static class MeterProviderBuilderExtensions
     /// <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);
-
+        AddAspNetInstrumentation(builder, configure: null);
+
     /// <summary>
     /// Enables the incoming requests automatic data collection for ASP.NET.
     /// </summary>

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

@@ -29,23 +29,25 @@ namespace OpenTelemetry.Instrumentation.AspNet.Tests;
 public class HttpInMetricsListenerTests
 {
     [Theory]
-    [InlineData("http://localhost/", 0, null, null, "http")]
-    [InlineData("https://localhost/", 0, null, null, "https")]
-    [InlineData("http://localhost/api/value", 0, null, null, "http")]
-    [InlineData("http://localhost/api/value", 1, "{controller}/{action}", null, "http")]
-    [InlineData("http://localhost/api/value", 2, "{controller}/{action}", null, "http")]
-    [InlineData("http://localhost/api/value", 3, "{controller}/{action}", null, "http")]
-    [InlineData("http://localhost/api/value", 4, "{controller}/{action}", null, "http")]
-    [InlineData("http://localhost:8080/api/value", 0, null, null, "http")]
-    [InlineData("http://localhost:8080/api/value", 1, "{controller}/{action}", null, "http")]
-    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", "enrich", "http")]
-    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", "throw", "http")]
-    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", null, "http")]
+    [InlineData("http://localhost/", 0, null, null, null, "http")]
+    [InlineData("https://localhost/", 0, null, null, null, "https")]
+    [InlineData("http://localhost/api/value", 0, null, null, null, "http")]
+    [InlineData("http://localhost/api/value", 1, "{controller}/{action}", null, null, "http")]
+    [InlineData("http://localhost/api/value", 2, "{controller}/{action}", null, null, "http")]
+    [InlineData("http://localhost/api/value", 3, "{controller}/{action}", null, null, "http")]
+    [InlineData("http://localhost/api/value", 4, "{controller}/{action}", null, null, "http")]
+    [InlineData("http://localhost:8080/api/value", 0, null, null, null, "http")]
+    [InlineData("http://localhost:8080/api/value", 1, "{controller}/{action}", null, null, "http")]
+    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", "enrich", null, "http")]
+    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", "throw", null, "http")]
+    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", null, "on", "http")]
+    [InlineData("http://localhost:8080/api/value", 3, "{controller}/{action}", null, null, "http")]
     public void AspNetMetricTagsAreCollectedSuccessfully(
         string url,
         int routeType,
         string routeTemplate,
         string enrichMode,
+        string filterMode,
         string expectedScheme)
     {
         double duration = 0;
@@ -81,6 +83,17 @@ public void AspNetMetricTagsAreCollectedSuccessfully(
                         tags.Add("enriched", "true");
                     }
                 };
+
+                options.Filter += (HttpContext httpContext) =>
+                {
+                    // If filterMode is on, filter out the current metric
+                    if (filterMode == "on")
+                    {
+                        return false;
+                    }
+
+                    return true;
+                };
             })
             .AddInMemoryExporter(exportedItems)
             .Build();
@@ -91,6 +104,13 @@ public void AspNetMetricTagsAreCollectedSuccessfully(
 
         meterProvider.ForceFlush();
 
+        // If filtering is enabled, we should have collected no data.
+        if (filterMode == "on")
+        {
+            Assert.Empty(exportedItems);
+            return;
+        }
+
         Assert.Single(exportedItems);
 
         var metricPoints = new List<MetricPoint>();
@@ -118,6 +138,12 @@ public void AspNetMetricTagsAreCollectedSuccessfully(
             expectedTagCount++;
         }
 
+        var expectedMetricPoints = 1;
+        if (filterMode == "on")
+        {
+            expectedMetricPoints++;
+        }
+
         Assert.Equal(expectedTagCount, metricPoints[0].Tags.Count);
         Dictionary<string, object?> tags = new(metricPoint.Tags.Count);
         foreach (var tag in metricPoint.Tags)