Add more context into ActivityIsNull logging

Src/DependencyCollector/Shared/HttpCoreDiagnosticSourceListener.cs

@@ -251,22 +251,24 @@ public void Dispose()
         /// </summary>
         internal void OnException(Exception exception, HttpRequestMessage request)
         {
+            // Even though we have the IsEnabled filter, to reject ApplicationInsights URLs before any events are fired,
+            // Exceptions are special and fired even if request instrumentation is disabled.
+            if (this.applicationInsightsUrlFilter.IsApplicationInsightsUrl(request.RequestUri))
+            {
+                return;
+            }
+
             Activity currentActivity = Activity.Current;
             if (currentActivity == null)
             {
-                DependencyCollectorEventSource.Log.CurrentActivityIsNull();
+                DependencyCollectorEventSource.Log.CurrentActivityIsNull(HttpExceptionEventName);
                 return;
             }
 
             DependencyCollectorEventSource.Log.HttpCoreDiagnosticSourceListenerException(currentActivity.Id);
 
-            // Even though we have the IsEnabled filter, to reject ApplicationInsights URLs before any events are fired,
-            // Exceptions are special and fired even if request instrumentation is disabled.
-            if (!this.applicationInsightsUrlFilter.IsApplicationInsightsUrl(request.RequestUri))
-            {
-                this.pendingExceptions.TryAdd(currentActivity.Id, exception);
-                this.client.TrackException(exception);
-            }
+            this.pendingExceptions.TryAdd(currentActivity.Id, exception);
+            this.client.TrackException(exception);
         }
 
         //// netcoreapp 2.0 event
@@ -276,21 +278,23 @@ internal void OnException(Exception exception, HttpRequestMessage request)
         /// </summary>
         internal void OnActivityStart(HttpRequestMessage request)
         {
+            // Even though we have the IsEnabled filter to reject ApplicationInsights URLs before any events are fired, if there
+            // are multiple subscribers and one subscriber returns true to IsEnabled then all subscribers will receive the event.
+            if (this.applicationInsightsUrlFilter.IsApplicationInsightsUrl(request.RequestUri))
+            {
+                return;
+            }
+
             var currentActivity = Activity.Current;
             if (currentActivity == null)
             {
-                DependencyCollectorEventSource.Log.CurrentActivityIsNull();
+                DependencyCollectorEventSource.Log.CurrentActivityIsNull(HttpOutStartEventName);
                 return;
             }
 
             DependencyCollectorEventSource.Log.HttpCoreDiagnosticSourceListenerStart(currentActivity.Id);
 
-            // Even though we have the IsEnabled filter to reject ApplicationInsights URLs before any events are fired, if there
-            // are multiple subscribers and one subscriber returns true to IsEnabled then all subscribers will receive the event.
-            if (!this.applicationInsightsUrlFilter.IsApplicationInsightsUrl(request.RequestUri))
-            {
-                this.InjectRequestHeaders(request, this.configuration.InstrumentationKey);
-            }
+            this.InjectRequestHeaders(request, this.configuration.InstrumentationKey);
         }
 
         //// netcoreapp 2.0 event
@@ -300,22 +304,22 @@ internal void OnActivityStart(HttpRequestMessage request)
         /// </summary>
         internal void OnActivityStop(HttpResponseMessage response, HttpRequestMessage request, TaskStatus requestTaskStatus)
         {
-            Activity currentActivity = Activity.Current;
-            if (currentActivity == null)
+            // Even though we have the IsEnabled filter to reject ApplicationInsights URLs before any events are fired, if there
+            // are multiple subscribers and one subscriber returns true to IsEnabled then all subscribers will receive the event.
+            if (this.applicationInsightsUrlFilter.IsApplicationInsightsUrl(request.RequestUri))
             {
-                DependencyCollectorEventSource.Log.CurrentActivityIsNull();
                 return;
             }
 
-            DependencyCollectorEventSource.Log.HttpCoreDiagnosticSourceListenerStop(currentActivity.Id);
-
-            // Even though we have the IsEnabled filter to reject ApplicationInsights URLs before any events are fired, if there
-            // are multiple subscribers and one subscriber returns true to IsEnabled then all subscribers will receive the event.
-            if (this.applicationInsightsUrlFilter.IsApplicationInsightsUrl(request.RequestUri))
+            Activity currentActivity = Activity.Current;
+            if (currentActivity == null)
             {
+                DependencyCollectorEventSource.Log.CurrentActivityIsNull(HttpOutStopEventName);
                 return;
             }
 
+            DependencyCollectorEventSource.Log.HttpCoreDiagnosticSourceListenerStop(currentActivity.Id);
+
             Uri requestUri = request.RequestUri;
             var resourceName = request.Method.Method + " " + requestUri.AbsolutePath;
 

Src/DependencyCollector/Shared/Implementation/DependencyCollectorEventSource.cs

@@ -248,11 +248,11 @@ public void EndAsyncExceptionCallbackCalled(string id, string appDomainName = "I
 
         [Event(
             23,
-            Message = "Current Activity is null",
+            Message = "Current Activity is null for event = '{0}'",
             Level = EventLevel.Error)]
-        public void CurrentActivityIsNull(string appDomainName = "Incorrect")
+        public void CurrentActivityIsNull(string diagnosticsSourceEventName, string appDomainName = "Incorrect")
         {
-            this.WriteEvent(23, this.ApplicationName);
+            this.WriteEvent(23, diagnosticsSourceEventName, this.ApplicationName);
         }
 
         [Event(

Src/DependencyCollector/Shared/Implementation/DiagnosticSourceListenerBase.cs

@@ -150,18 +150,18 @@ internal IndividualDiagnosticSourceListener(DiagnosticListener diagnosticListene
 
             public void OnNext(KeyValuePair<string, object> evnt)
             {
-                Activity currentActivity = Activity.Current;
-                if (currentActivity == null)
-                {
-                    DependencyCollectorEventSource.Log.CurrentActivityIsNull();
-                    return;
-                }
-
                 // while we provide IsEnabled callback during subscription, it does not gurantee events will not be fired
                 // In case of multiple subscribers, it's enough for one to reply true to IsEnabled.
                 // I.e. check for if activity is not disabled and particular handler wants to receive the event.
                 if (this.telemetryDiagnosticSourceListener.IsActivityEnabled(evnt.Key, this.Context) && this.eventHandler.IsEventEnabled(evnt.Key, null, null))
                 {
+                    Activity currentActivity = Activity.Current;
+                    if (currentActivity == null)
+                    {
+                        DependencyCollectorEventSource.Log.CurrentActivityIsNull(evnt.Key);
+                        return;
+                    }
+
                     DependencyCollectorEventSource.Log.TelemetryDiagnosticSourceListenerEvent(evnt.Key, currentActivity.Id);
 
                     try