Adding a trace source to events emmited by the HTTP trace handler

Author: fabiocav

src/WebJobs.Script.WebHost/Handlers/SystemTraceHandler.cs

@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
+using System;
+using System.Diagnostics;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
@@ -13,22 +15,37 @@ namespace Microsoft.Azure.WebJobs.Script.WebHost.Handlers
     public class SystemTraceHandler : DelegatingHandler
     {
         private readonly HttpConfiguration _config;
+        private TraceWriter _traceWriter;
 
         public SystemTraceHandler(HttpConfiguration config)
         {
             _config = config;
         }
 
+        private TraceWriter TraceWriter
+        {
+            get
+            {
+                if (_traceWriter == null)
+                {
+                    _traceWriter = _config.DependencyResolver
+                        .GetService<TraceWriter>()
+                        .WithSource(ScriptConstants.TraceSourceHttpHandler);
+                }
+
+                return _traceWriter;
+            }
+        }
+
         protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
         {
-            var traceWriter = _config.DependencyResolver.GetService<TraceWriter>();
             var details = new JObject
             {
                 { "requestId", request.GetRequestId() },
                 { "method", request.Method.ToString() },
                 { "uri", request.RequestUri.LocalPath.ToString() }
             };
-            traceWriter.Info($"Executing HTTP request: {details}");
+            TraceWriter.Info($"Executing HTTP request: {details}");
 
             var response = await base.SendAsync(request, cancellationToken);
 
@@ -39,14 +56,14 @@ protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage
                 { "uri", request.RequestUri.LocalPath.ToString() },
                 { "authorizationLevel", request.GetAuthorizationLevel().ToString() }
             };
-            traceWriter.Info($"Executed HTTP request: {details}");
+            TraceWriter.Info($"Executed HTTP request: {details}");
 
             details = new JObject
             {
                 { "requestId", request.GetRequestId() },
                 { "status", response.StatusCode.ToString() }
             };
-            traceWriter.Info($"Response details: {details}");
+            TraceWriter.Info($"Response details: {details}");
 
             return response;
         }

src/WebJobs.Script/ScriptConstants.cs

@@ -26,6 +26,7 @@ public static class ScriptConstants
         public const string TraceSourceHostAdmin = "HostAdmin";
         public const string TraceSourceFileWatcher = "FileWatcher";
         public const string TraceSourceSwagger = "SwaggerDocumentation";
+        public const string TraceSourceHttpHandler = "HttpRequestTraceHandler";
 
         // Define all system parameters we inject with a prefix to avoid collisions
         // with user parameters

test/WebJobs.Script.Tests/Handlers/SystemTraceHandlerTests.cs

@@ -57,18 +57,21 @@ public async Task SendAsync_WritesExpectedTraces()
             Assert.Equal(TraceLevel.Info, trace.Level);
             string message = Regex.Replace(trace.Message, @"\s+", string.Empty);
             Assert.Equal($"ExecutingHTTPrequest:{{\"requestId\":\"{requestId}\",\"method\":\"GET\",\"uri\":\"/api/testfunc\"}}", message);
+            Assert.Equal(ScriptConstants.TraceSourceHttpHandler, trace.Source);
 
             // validate executed trace
             trace = traces[1];
             Assert.Equal(TraceLevel.Info, trace.Level);
             message = Regex.Replace(trace.Message, @"\s+", string.Empty);
             Assert.Equal($"ExecutedHTTPrequest:{{\"requestId\":\"{requestId}\",\"method\":\"GET\",\"uri\":\"/api/testfunc\",\"authorizationLevel\":\"Function\"}}", message);
+            Assert.Equal(ScriptConstants.TraceSourceHttpHandler, trace.Source);
 
             // validate response trace
             trace = traces[2];
             Assert.Equal(TraceLevel.Info, trace.Level);
             message = Regex.Replace(trace.Message, @"\s+", string.Empty);
             Assert.Equal($"Responsedetails:{{\"requestId\":\"{requestId}\",\"status\":\"OK\"}}", message);
+            Assert.Equal(ScriptConstants.TraceSourceHttpHandler, trace.Source);
         }
     }
 }