Add propagation to filtered out events from HttpClient

src/OpenTelemetry.Instrumentation.Http/CHANGELOG.md

@@ -6,6 +6,12 @@
   description/reason phrase for outgoing http spans.
   ([#1579](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1579))
 
+* Moved the DiagnosticListener filtering logic from HttpClientInstrumentation
+  ctor to OnStartActivity method of HttpHandlerDiagnosticListener.cs; Updated
+  the logic of OnStartActivity to inject propagation data into Headers for
+  filtered out events as well.
+  ([#1707](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1707))
+
 ## 1.0.0-rc1.1
 
 Released 2020-Nov-17

src/OpenTelemetry.Instrumentation.Http/HttpClientInstrumentation.cs

@@ -33,7 +33,7 @@ internal class HttpClientInstrumentation : IDisposable
         /// <param name="options">Configuration options for HTTP client instrumentation.</param>
         public HttpClientInstrumentation(ActivitySourceAdapter activitySourceAdapter, HttpClientInstrumentationOptions options)
         {
-            this.diagnosticSourceSubscriber = new DiagnosticSourceSubscriber(new HttpHandlerDiagnosticListener(options, activitySourceAdapter), (activityName, arg1, arg2) => options?.EventFilter(activityName, arg1) ?? true);
+            this.diagnosticSourceSubscriber = new DiagnosticSourceSubscriber(new HttpHandlerDiagnosticListener(options, activitySourceAdapter), null);
             this.diagnosticSourceSubscriber.Subscribe();
         }
 

src/OpenTelemetry.Instrumentation.Http/Implementation/HttpHandlerDiagnosticListener.cs

@@ -82,6 +82,29 @@ public override void OnStartActivity(Activity activity, object payload)
                 return;
             }
 
+            var textMapPropagator = Propagators.DefaultTextMapPropagator;
+
+            if (!(this.httpClientSupportsW3C && textMapPropagator is TraceContextPropagator))
+            {
+                textMapPropagator.Inject(new PropagationContext(activity.Context, Baggage.Current), request, HttpRequestMessageContextPropagation.HeaderValueSetter);
+            }
+
+            try
+            {
+                if (this.options.EventFilter(activity.OperationName, request) == false)
+                {
+                    HttpInstrumentationEventSource.Log.RequestIsFilteredOut(activity.OperationName);
+                    activity.IsAllDataRequested = false;
+                    return;
+                }
+            }
+            catch (Exception ex)
+            {
+                HttpInstrumentationEventSource.Log.RequestFilterException(ex);
+                activity.IsAllDataRequested = false;
+                return;
+            }
+
             activity.DisplayName = HttpTagHelper.GetOperationNameForHttpMethod(request.Method);
 
             this.activitySource.Start(activity, ActivityKind.Client, ActivitySource);
@@ -106,13 +129,6 @@ public override void OnStartActivity(Activity activity, object payload)
                     HttpInstrumentationEventSource.Log.EnrichmentException(ex);
                 }
             }
-
-            var textMapPropagator = Propagators.DefaultTextMapPropagator;
-
-            if (!(this.httpClientSupportsW3C && textMapPropagator is TraceContextPropagator))
-            {
-                textMapPropagator.Inject(new PropagationContext(activity.Context, Baggage.Current), request, HttpRequestMessageContextPropagation.HeaderValueSetter);
-            }
         }
 
         public override void OnStopActivity(Activity activity, object payload)

src/OpenTelemetry.Instrumentation.Http/Implementation/HttpInstrumentationEventSource.cs

@@ -93,5 +93,11 @@ public void EnrichmentException(string exception)
         {
             this.WriteEvent(5, exception);
         }
+
+        [Event(6, Message = "Request is filtered out.", Level = EventLevel.Verbose)]
+        public void RequestIsFilteredOut(string eventName)
+        {
+            this.WriteEvent(6, eventName);
+        }
     }
 }