parseHeaders flag support (#47)

* parseHeaders flag support

Author: Mikhail-msft

src/Microsoft.AspNet.TelemetryCorrelation/ActivityHelper.cs

@@ -141,14 +141,19 @@ public static void StopRestoredActivity(Activity activity, HttpContext context)
         /// Creates root (first level) activity that describes incoming request.
         /// </summary>
         /// <param name="context">Current HttpContext.</param>
+        /// <param name="parseHeaders">Determines if headers should be parsed get correlation ids.</param>
         /// <returns>New root activity.</returns>
-        public static Activity CreateRootActivity(HttpContext context)
+        public static Activity CreateRootActivity(HttpContext context, bool parseHeaders)
         {
             if (AspNetListener.IsEnabled() && AspNetListener.IsEnabled(AspNetActivityName))
             {
                 var rootActivity = new Activity(AspNetActivityName);
 
-                rootActivity.Extract(context.Request.Unvalidated.Headers);
+                if (parseHeaders)
+                {
+                    rootActivity.Extract(context.Request.Unvalidated.Headers);
+                }
+
                 if (StartAspNetActivity(rootActivity))
                 {
                     context.Items[ActivityKey] = rootActivity;

src/Microsoft.AspNet.TelemetryCorrelation/TelemetryCorrelationHttpModule.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.Reflection;
 using System.Web;
@@ -21,6 +22,12 @@ static TelemetryCorrelationHttpModule()
             onStepMethodInfo = typeof(HttpApplication).GetMethod("OnExecuteRequestStep");
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether TelemetryCorrelationHttpModule should parse headers to get correlation ids.
+        /// </summary>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public bool ParseHeaders { get; set; } = true;
+
         /// <inheritdoc />
         public void Dispose()
         {
@@ -78,7 +85,7 @@ private void Application_BeginRequest(object sender, EventArgs e)
         {
             var context = ((HttpApplication)sender).Context;
             AspNetTelemetryCorrelationEventSource.Log.TraceCallback("Application_BeginRequest");
-            ActivityHelper.CreateRootActivity(context);
+            ActivityHelper.CreateRootActivity(context, ParseHeaders);
             context.Items[BeginCalledFlag] = true;
         }
 
@@ -99,7 +106,7 @@ private void Application_EndRequest(object sender, EventArgs e)
             if (!context.Items.Contains(BeginCalledFlag))
             {
                 // Activity has never been started
-                var activity = ActivityHelper.CreateRootActivity(context);
+                var activity = ActivityHelper.CreateRootActivity(context, ParseHeaders);
                 ActivityHelper.StopAspNetActivity(activity, context.Items);
             }
             else

test/Microsoft.AspNet.TelemetryCorrelation.Tests/ActivityHelperTest.cs

@@ -259,7 +259,7 @@ public void Stop_Root_Activity_With_129_Nesting_Depth()
         public void Should_Not_Create_RootActivity_If_AspNetListener_Not_Enabled()
         {
             var context = HttpContextHelper.GetFakeHttpContext();
-            var rootActivity = ActivityHelper.CreateRootActivity(context);
+            var rootActivity = ActivityHelper.CreateRootActivity(context, true);
 
             Assert.Null(rootActivity);
         }
@@ -269,7 +269,7 @@ public void Should_Not_Create_RootActivity_If_AspNetActivity_Not_Enabled()
         {
             var context = HttpContextHelper.GetFakeHttpContext();
             this.EnableAspNetListenerOnly();
-            var rootActivity = ActivityHelper.CreateRootActivity(context);
+            var rootActivity = ActivityHelper.CreateRootActivity(context, true);
 
             Assert.Null(rootActivity);
         }
@@ -279,7 +279,7 @@ public void Should_Not_Create_RootActivity_If_AspNetActivity_Not_Enabled_With_Ar
         {
             var context = HttpContextHelper.GetFakeHttpContext();
             this.EnableAspNetListenerAndDisableActivity();
-            var rootActivity = ActivityHelper.CreateRootActivity(context);
+            var rootActivity = ActivityHelper.CreateRootActivity(context, true);
 
             Assert.Null(rootActivity);
         }
@@ -289,27 +289,45 @@ public void Can_Create_RootActivity_And_Restore_Info_From_Request_Header()
         {
             var requestHeaders = new Dictionary<string, string>
             {
-                { ActivityExtensions.RequestIDHeaderName, "|aba2f1e978b2cab6.1" },
+                { ActivityExtensions.RequestIDHeaderName, "|aba2f1e978b2cab6.1." },
                 { ActivityExtensions.CorrelationContextHeaderName, this.baggageInHeader }
             };
 
             var context = HttpContextHelper.GetFakeHttpContext(headers: requestHeaders);
             this.EnableAspNetListenerAndActivity();
-            var rootActivity = ActivityHelper.CreateRootActivity(context);
+            var rootActivity = ActivityHelper.CreateRootActivity(context, true);
 
             Assert.NotNull(rootActivity);
-            Assert.True(rootActivity.ParentId == "|aba2f1e978b2cab6.1");
+            Assert.True(rootActivity.ParentId == "|aba2f1e978b2cab6.1.");
             var expectedBaggage = this.baggageItems.OrderBy(item => item.Value);
             var actualBaggage = rootActivity.Baggage.OrderBy(item => item.Value);
             Assert.Equal(expectedBaggage, actualBaggage);
         }
 
+        [Fact]
+        public void Can_Create_RootActivity_And_Ignore_Info_From_Request_Header_If_ParseHeaders_Is_False()
+        {
+            var requestHeaders = new Dictionary<string, string>
+            {
+                { ActivityExtensions.RequestIDHeaderName, "|aba2f1e978b2cab6.1." },
+                { ActivityExtensions.CorrelationContextHeaderName, this.baggageInHeader }
+            };
+
+            var context = HttpContextHelper.GetFakeHttpContext(headers: requestHeaders);
+            this.EnableAspNetListenerAndActivity();
+            var rootActivity = ActivityHelper.CreateRootActivity(context, parseHeaders: false);
+
+            Assert.NotNull(rootActivity);
+            Assert.Null(rootActivity.ParentId);
+            Assert.Empty(rootActivity.Baggage);
+        }
+
         [Fact]
         public void Can_Create_RootActivity_And_Start_Activity()
         {
             var context = HttpContextHelper.GetFakeHttpContext();
             this.EnableAspNetListenerAndActivity();
-            var rootActivity = ActivityHelper.CreateRootActivity(context);
+            var rootActivity = ActivityHelper.CreateRootActivity(context, true);
 
             Assert.NotNull(rootActivity);
             Assert.True(!string.IsNullOrEmpty(rootActivity.Id));
@@ -320,7 +338,7 @@ public void Can_Create_RootActivity_And_Saved_In_HttContext()
         {
             var context = HttpContextHelper.GetFakeHttpContext();
             this.EnableAspNetListenerAndActivity();
-            var rootActivity = ActivityHelper.CreateRootActivity(context);
+            var rootActivity = ActivityHelper.CreateRootActivity(context, true);
 
             Assert.NotNull(rootActivity);
             Assert.Same(rootActivity, context.Items[ActivityHelper.ActivityKey]);