Test fixup.

src/OpenTelemetry.Instrumentation.AspNet/AspNetInstrumentationOptions.cs

@@ -37,11 +37,6 @@ public class AspNetInstrumentationOptions
         /// <summary>
         /// Gets or sets a hook to exclude calls based on domain or other per-request criterion.
         /// </summary>
-        internal Predicate<HttpContext> RequestFilter { get; set; } = DefaultFilter;
-
-        private static bool DefaultFilter(HttpContext httpContext)
-        {
-            return true;
-        }
+        internal Predicate<HttpContext> RequestFilter { get; set; }
     }
 }

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

@@ -49,7 +49,7 @@ public override void OnStartActivity(Activity activity, object payload)
                 return;
             }
 
-            if (this.options.RequestFilter != null && !this.options.RequestFilter(context))
+            if (this.options.RequestFilter?.Invoke(context) == false)
             {
                 AspNetInstrumentationEventSource.Log.RequestIsFilteredOut(activity.OperationName);
                 activity.IsAllDataRequested = false;
@@ -121,6 +121,7 @@ public override void OnStartActivity(Activity activity, object payload)
         public override void OnStopActivity(Activity activity, object payload)
         {
             Activity activityToEnrich = activity;
+            Activity createdActivity = null;
 
             if (!(this.options.TextFormat is TraceContextFormat))
             {
@@ -132,9 +133,10 @@ public override void OnStopActivity(Activity activity, object payload)
                 if (activity.OperationName.Equals("Microsoft.AspNet.HttpReqIn.Start"))
                 {
                     // This block is hit if Asp.Net did restore Current to its own activity,
-                    // then we need to retrieve the one created by HttpInListener
-                    // and populate tags to it.
-                    activityToEnrich = (Activity)activity.GetCustomProperty("ActivityByHttpInListener");
+                    // and we need to retrieve the one created by HttpInListener,
+                    // or an additional activity was never created.
+                    createdActivity = (Activity)activity.GetCustomProperty("ActivityByHttpInListener");
+                    activityToEnrich = createdActivity ?? activity;
                 }
             }
 
@@ -197,13 +199,12 @@ public override void OnStopActivity(Activity activity, object payload)
                     var activityByAspNet = (Activity)activity.GetCustomProperty("ActivityByAspNet");
                     Activity.Current = activityByAspNet;
                 }
-                else if (activity.OperationName.Equals("Microsoft.AspNet.HttpReqIn.Start"))
+                else if (createdActivity != null)
                 {
                     // This block is hit if Asp.Net did restore Current to its own activity,
                     // then we need to retrieve the one created by HttpInListener
                     // and stop it.
-                    var activityByHttpInListener = (Activity)activity.GetCustomProperty("ActivityByHttpInListener");
-                    activityByHttpInListener.Stop();
+                    createdActivity.Stop();
 
                     // Restore current back to the one created by Asp.Net
                     Activity.Current = activity;

src/OpenTelemetry.Instrumentation.AspNetCore/AspNetCoreInstrumentationOptions.cs

@@ -37,11 +37,6 @@ public class AspNetCoreInstrumentationOptions
         /// <summary>
         /// Gets or sets a hook to exclude calls based on domain or other per-request criterion.
         /// </summary>
-        internal Predicate<HttpContext> RequestFilter { get; set; } = DefaultFilter;
-
-        private static bool DefaultFilter(HttpContext httpContext)
-        {
-            return true;
-        }
+        internal Predicate<HttpContext> RequestFilter { get; set; }
     }
 }

src/OpenTelemetry.Instrumentation.AspNetCore/Implementation/HttpInListener.cs

@@ -57,7 +57,7 @@ public override void OnStartActivity(Activity activity, object payload)
                 return;
             }
 
-            if (this.options.RequestFilter != null && !this.options.RequestFilter(context))
+            if (this.options.RequestFilter?.Invoke(context) == false)
             {
                 AspNetCoreInstrumentationEventSource.Log.RequestIsFilteredOut(activity.OperationName);
                 activity.IsAllDataRequested = false;

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

@@ -53,10 +53,8 @@ public void Dispose()
         [InlineData("https://localhost:443/about_attr_route/10", 2, "about_attr_route/{customerId}", "TraceContext")]
         [InlineData("http://localhost:1880/api/weatherforecast", 3, "api/{controller}/{id}", "TraceContext")]
         [InlineData("https://localhost:1843/subroute/10", 4, "subroute/{customerId}", "TraceContext")]
-
-        // TODO: Reenable this tests once filtering mechanism is designed.
-        // [InlineData("http://localhost/api/value", 0, null, "/api/value")] // Request will be filtered
-        // [InlineData("http://localhost/api/value", 0, null, "{ThrowException}")] // Filter user code will throw an exception
+        [InlineData("http://localhost/api/value", 0, null, "TraceContext", "/api/value")] // Request will be filtered
+        [InlineData("http://localhost/api/value", 0, null, "TraceContext", "{ThrowException}")] // Filter user code will throw an exception
         [InlineData("http://localhost/api/value/2", 0, null, "CustomContext", "/api/value")] // Request will not be filtered
         [InlineData("http://localhost/api/value/2", 0, null, "CustomContext", "/api/value", true)] // Request will not be filtered
         public void AspNetRequestsAreCollectedSuccessfully(
@@ -188,7 +186,19 @@ public void AspNetRequestsAreCollectedSuccessfully(
 
             if (HttpContext.Current.Request.Path == filter || filter == "{ThrowException}")
             {
-                Assert.Equal(0, activityProcessor.Invocations.Count); // Nothing was called because request was filtered.
+                if (filter == "{ThrowException}")
+                {
+                    // This behavior is not good. If filter throws, Stop is called without Start.
+                    // Need to do something here, but user can't currently set the filter
+                    // so it wil always noop. When we support user filter,
+                    // treat this as a todo: define exception behavior.
+                    Assert.Equal(2, activityProcessor.Invocations.Count); // Stop & Disposed called.
+                }
+                else
+                {
+                    Assert.Equal(1, activityProcessor.Invocations.Count); // Only disposed was called because request was filtered.
+                }
+
                 return;
             }