Instrument HttpClientHandler on netfx with DiagnosticSource/Activity

src/System.Net.Http/src/System.Net.Http.csproj

@@ -40,6 +40,8 @@
     <Compile Include="System\Net\Http\ByteArrayContent.cs" />
     <Compile Include="System\Net\Http\ClientCertificateOption.cs" />
     <Compile Include="System\Net\Http\DelegatingHandler.cs" />
+    <Compile Include="System\Net\Http\DiagnosticsHandler.cs" />    
+    <Compile Include="System\Net\Http\DiagnosticsHandlerLoggingStrings.cs"/>        
     <Compile Include="System\Net\Http\FormUrlEncodedContent.cs" />
     <Compile Include="System\Net\Http\HttpClient.cs" />
     <Compile Include="System\Net\Http\HttpCompletionOption.cs" />
@@ -119,8 +121,6 @@
   </ItemGroup>
   <!-- Common, except for Windows net46 build -->
   <ItemGroup Condition="'$(TargetGroup)' != 'net46'  And '$(TargetGroup)' != 'netfx'">
-    <Compile Include="System\Net\Http\DiagnosticsHandler.cs" />    
-    <Compile Include="System\Net\Http\DiagnosticsHandlerLoggingStrings.cs"/>    
     <Compile Include="$(CommonPath)\System\Net\Mail\DomainLiteralReader.cs">
       <Link>Common\System\Net\Mail\DomainLiteralReader.cs</Link>
     </Compile>
@@ -179,6 +179,7 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Runtime" />
+    <ProjectReference Include="..\..\System.Diagnostics.DiagnosticSource\src\System.Diagnostics.DiagnosticSource.csproj" />
   </ItemGroup>
   <!-- Unix -->
   <PropertyGroup Condition=" '$(TargetsUnix)' == 'true' ">

src/System.Net.Http/src/System/Net/Http/DiagnosticsHandler.cs

@@ -13,15 +13,15 @@ namespace System.Net.Http
     /// <summary>
     /// DiagnosticHandler notifies DiagnosticSource subscribers about outgoing Http requests
     /// </summary>
-    internal sealed class DiagnosticsHandler : DelegatingHandler
+    internal sealed class DiagnosticsHandler
     {
         /// <summary>
         /// DiagnosticHandler constructor
         /// </summary>
-        /// <param name="innerHandler">Inner handler: Windows or Unix implementation of HttpMessageHandler. 
-        /// Note that DiagnosticHandler is the latest in the pipeline </param>
-        public DiagnosticsHandler(HttpMessageHandler innerHandler) : base(innerHandler)
+        /// <param name="sendAsync">referene to HttpClientHandler.SendAsync (Windows\Linux\Win Desktop)</param>
+        public DiagnosticsHandler(Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> sendAsync)
         {
+            _sendAsync = sendAsync;
         }
 
         internal static bool IsEnabled()
@@ -30,7 +30,7 @@ internal static bool IsEnabled()
             return s_diagnosticListener.IsEnabled();
         }
 
-        protected internal override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
+        internal async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
             CancellationToken cancellationToken)
         {
             //HttpClientHandler is responsible to call DiagnosticsHandler.IsEnabled() before forwarding request here.
@@ -55,6 +55,7 @@ protected internal override async Task<HttpResponseMessage> SendAsync(HttpReques
                     activity.Start();
                 }
             }
+#if !NET46
             //if Activity events are disabled, try to write System.Net.Http.Request event (deprecated)
             else if (s_diagnosticListener.IsEnabled(DiagnosticsHandlerLoggingStrings.RequestWriteNameDeprecated))
             {
@@ -69,7 +70,7 @@ protected internal override async Task<HttpResponseMessage> SendAsync(HttpReques
                     }
                 );
             }
-
+#endif
             // If we are on at all, we propagate any activity information.  
             Activity currentActivity = Activity.Current;
             if (currentActivity != null)
@@ -92,7 +93,7 @@ protected internal override async Task<HttpResponseMessage> SendAsync(HttpReques
                 }
             }
 
-            Task<HttpResponseMessage> responseTask = base.SendAsync(request, cancellationToken);
+            Task<HttpResponseMessage> responseTask = _sendAsync(request, cancellationToken);
             try
             {
                 await responseTask.ConfigureAwait(false);
@@ -128,6 +129,7 @@ protected internal override async Task<HttpResponseMessage> SendAsync(HttpReques
                         RequestTaskStatus = responseTask.Status
                     });
                 }
+#if !NET46
                 //if Activity events are disabled, try to write System.Net.Http.Response event (deprecated)
                 else if (s_diagnosticListener.IsEnabled(DiagnosticsHandlerLoggingStrings.ResponseWriteNameDeprecated))
                 {
@@ -142,15 +144,18 @@ protected internal override async Task<HttpResponseMessage> SendAsync(HttpReques
                         }
                     );
                 }
+#endif
             }
+
             return responseTask.Result;
         }
 
-        #region private
+#region private
 
+        private readonly Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> _sendAsync;
         private static readonly DiagnosticListener s_diagnosticListener =
             new DiagnosticListener(DiagnosticsHandlerLoggingStrings.DiagnosticListenerName);
 
-        #endregion
+#endregion
     }
 }

src/System.Net.Http/src/System/Net/Http/DiagnosticsHandlerLoggingStrings.cs

@@ -10,8 +10,11 @@ namespace System.Net.Http
     internal static class DiagnosticsHandlerLoggingStrings
     {
         public const string DiagnosticListenerName = "HttpHandlerDiagnosticListener";
+
+#if !NET46
         public const string RequestWriteNameDeprecated = "System.Net.Http.Request";
         public const string ResponseWriteNameDeprecated = "System.Net.Http.Response";
+#endif
 
         public const string ExceptionEventName = "System.Net.Http.Exception";
         public const string ActivityName = "System.Net.Http.Activity";

src/System.Net.Http/src/System/Net/Http/HttpClientHandler.Net46.cs

@@ -58,6 +58,8 @@ private Func<
             SslPolicyErrors,
             bool> _serverCertificateCustomValidationCallback;
 
+        private readonly DiagnosticsHandler _diagnosticsPipeline;
+
         #endregion Fields
 
         #region Properties
@@ -446,6 +448,7 @@ public HttpClientHandler()
             _properties = null; // only create collection when required.
             _maxConnectionsPerServer = ServicePointManager.DefaultConnectionLimit;
             _serverCertificateCustomValidationCallback = null;
+            _diagnosticsPipeline = new DiagnosticsHandler(this.SendAsyncImpl);
         }
 
         protected override void Dispose(bool disposing)
@@ -753,9 +756,19 @@ private static void SetContentHeaders(HttpWebRequest webRequest, HttpRequestMess
         #endregion Message Setup
 
         #region Request Processing
-
+        
         protected internal override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
             CancellationToken cancellationToken)
+        {
+            if (DiagnosticsHandler.IsEnabled())
+            {
+                return _diagnosticsPipeline.SendAsync(request, cancellationToken);
+            }
+            return SendAsyncImpl(request, cancellationToken);
+        }
+
+        internal Task<HttpResponseMessage> SendAsyncImpl(HttpRequestMessage request,
+            CancellationToken cancellationToken)
         {
             if (request == null)
             {

src/System.Net.Http/src/System/Net/Http/HttpClientHandler.Unix.cs

@@ -143,7 +143,7 @@ public IDictionary<String, object> Properties
         public HttpClientHandler()
         {
             _curlHandler = new CurlHandler();
-            _diagnosticsPipeline = new DiagnosticsHandler(_curlHandler);
+            _diagnosticsPipeline = new DiagnosticsHandler(_curlHandler.SendAsync);
         }
 
         protected override void Dispose(bool disposing)

src/System.Net.Http/src/System/Net/Http/HttpClientHandler.Windows.cs

@@ -194,7 +194,7 @@ public IDictionary<String, object> Properties
         public HttpClientHandler()
         {
             _winHttpHandler = new WinHttpHandler();
-            _diagnosticsPipeline = new DiagnosticsHandler(_winHttpHandler);
+            _diagnosticsPipeline = new DiagnosticsHandler(_winHttpHandler.SendAsync);
 
             // Adjust defaults to match current .NET Desktop HttpClientHandler (based on HWR stack).
             AllowAutoRedirect = true;

src/System.Net.Http/src/netcore50/System/Net/HttpClientHandler.cs

@@ -37,7 +37,7 @@ public class HttpClientHandler : HttpMessageHandler
 
         private readonly RTHttpBaseProtocolFilter rtFilter;
         private readonly HttpHandlerToFilter handlerToFilter;
-        private readonly HttpMessageHandler diagnosticsPipeline;
+        private readonly DiagnosticsHandler diagnosticsPipeline;
 
         private volatile bool operationStarted;
         private volatile bool disposed;
@@ -422,7 +422,7 @@ public HttpClientHandler()
         {
             this.rtFilter = new RTHttpBaseProtocolFilter();
             this.handlerToFilter = new HttpHandlerToFilter(this.rtFilter);
-            this.diagnosticsPipeline = new DiagnosticsHandler(handlerToFilter);
+            this.diagnosticsPipeline = new DiagnosticsHandler(handlerToFilter.SendAsync);
 
             this.clientCertificateOptions = ClientCertificateOption.Manual;