fix: Fix bug in distributed tracing when excludeNewrelicHeader is set to true

src/Agent/NewRelic/Agent/Core/DistributedTracing/DistributedTracePayloadHandler.cs

@@ -74,6 +74,10 @@ public void InsertDistributedTraceHeaders<T>(IInternalTransaction transaction, T
                         setter(carrier, Constants.DistributedTracePayloadKeyAllLower, distributedTracePayload);
                     }
                 }
+                else
+                {
+                    transaction.SetSampled(_adaptiveSampler);
+                }
 
                 var createOutboundTraceContextHeadersSuccess = false;
                 try

tests/Agent/IntegrationTests/IntegrationTestHelpers/NewRelicConfigModifier.cs

@@ -243,6 +243,25 @@ public void SetOrDeleteDistributedTraceEnabled(bool? enabled)
             }
         }
 
+        /// <summary>
+        /// Sets or deletes the excludeNewrelicHeader setting in the newrelic.config.
+        /// </summary>
+        /// <param name="enabled">If null, the setting will be deleted; otherwise, the setting will be set to the value of this parameter.</param>
+        public void SetOrDeleteDistributedTraceExcludeNewRelicHeader(bool? exclude)
+        {
+            const string config = "configuration";
+            const string distributedTracing = "distributedTracing";
+            if (null == exclude)
+            {
+                CommonUtils.DeleteXmlNodeFromNewRelicConfig(_configFilePath, new[] { config }, distributedTracing);
+            }
+            else
+            {
+                CommonUtils.ModifyOrCreateXmlAttributeInNewRelicConfig(_configFilePath, new[] { config, distributedTracing },
+                    "excludeNewrelicHeader", exclude.Value ? "true" : "false");
+            }
+        }
+
         public NewRelicConfigModifier SetAllowAllHeaders(bool? enabled)
         {
             const string config = "configuration";

tests/Agent/IntegrationTests/IntegrationTests/DistributedTracing/W3CInstrumentationTests/HttpClientW3CTestsNetCore.cs

@@ -19,7 +19,7 @@ namespace NewRelic.Agent.IntegrationTests.DistributedTracing.W3CInstrumentationT
     /// Instrumentations occur in this test are AspNetCore and HttpClient.
     /// </summary>
     [NetCoreTest]
-    public class HttpClientW3CTestsNetCore : NewRelicIntegrationTest<AspNetCoreDistTraceRequestChainFixture>
+    public abstract class HttpClientW3CTestsNetCore : NewRelicIntegrationTest<AspNetCoreDistTraceRequestChainFixture>
     {
         private readonly AspNetCoreDistTraceRequestChainFixture _fixture;
 
@@ -30,11 +30,12 @@ public class HttpClientW3CTestsNetCore : NewRelicIntegrationTest<AspNetCoreDistT
         private const string TestTracingVendors = "rojo,congo";
         private const string TestOtherVendorEntries = "rojo=1,congo=2";
 
-        public HttpClientW3CTestsNetCore(AspNetCoreDistTraceRequestChainFixture fixture, ITestOutputHelper output)
+        public HttpClientW3CTestsNetCore(AspNetCoreDistTraceRequestChainFixture fixture, ITestOutputHelper output, bool excludeNewRelicHeader)
             : base(fixture)
         {
             _fixture = fixture;
             _fixture.TestLogger = output;
+            _fixture.ExcludeNewRelicHeader = excludeNewRelicHeader;
             _fixture.AddActions
             (
                 exerciseApplication: () =>
@@ -46,7 +47,6 @@ public HttpClientW3CTestsNetCore(AspNetCoreDistTraceRequestChainFixture fixture,
                     };
 
                     _fixture.ExecuteTraceRequestChain("CallNext", "CallNext", "CallEnd", headers);
-
                     _fixture.FirstCallAppAgentLog.WaitForLogLines(AgentLogBase.TransactionTransformCompletedLogLineRegex, TimeSpan.FromSeconds(15), ExpectedTransactionCount);
                     _fixture.SecondCallAppAgentLog.WaitForLogLines(AgentLogBase.TransactionTransformCompletedLogLineRegex, TimeSpan.FromSeconds(15), ExpectedTransactionCount);
                     _fixture.AgentLog.WaitForLogLines(AgentLogBase.TransactionTransformCompletedLogLineRegex, TimeSpan.FromSeconds(15), ExpectedTransactionCount);
@@ -120,13 +120,17 @@ public void Test()
 
             var senderExpectedMetrics = new List<Assertions.ExpectedMetric>
             {
-                new Assertions.ExpectedMetric { metricName = @"Supportability/DistributedTrace/CreatePayload/Success", callCount = 1 },
                 new Assertions.ExpectedMetric { metricName = @"Supportability/SpanEvent/TotalEventsSeen", callCount = 4 },
                 new Assertions.ExpectedMetric { metricName = @"Supportability/TraceContext/Accept/Success", callCount = 1 },
                 new Assertions.ExpectedMetric { metricName = @"Supportability/TraceContext/Create/Success", callCount = 1 },
                 new Assertions.ExpectedMetric { metricName = @"Supportability/TraceContext/TraceState/NoNrEntry", callCount = 1 }
             };
 
+            if (! _fixture.ExcludeNewRelicHeader)
+            {
+                senderExpectedMetrics.Add(new Assertions.ExpectedMetric { metricName = @"Supportability/DistributedTrace/CreatePayload/Success", callCount = 1 });
+            }
+
             var accountId = _fixture.SecondCallAppAgentLog.GetAccountId();
             var appId = _fixture.SecondCallAppAgentLog.GetApplicationId();
 
@@ -157,4 +161,22 @@ public void Test()
             );
         }
     }
+
+    public class HttpClientW3CTestsNetCoreWithNRHeader : HttpClientW3CTestsNetCore
+    {
+        public HttpClientW3CTestsNetCoreWithNRHeader(AspNetCoreDistTraceRequestChainFixture fixture, ITestOutputHelper output)
+            : base(fixture, output, excludeNewRelicHeader: false)
+        {
+        }
+
+    }
+
+    public class HttpClientW3CTestsNetCoreWithoutNRHeader : HttpClientW3CTestsNetCore
+    {
+        public HttpClientW3CTestsNetCoreWithoutNRHeader(AspNetCoreDistTraceRequestChainFixture fixture, ITestOutputHelper output)
+            : base(fixture, output, excludeNewRelicHeader: true)
+        {
+        }
+    }
+
 }

tests/Agent/IntegrationTests/IntegrationTests/RemoteServiceFixtures/AspNetCoreDistTraceRequestChainFixture.cs

@@ -1,7 +1,6 @@
 // Copyright 2020 New Relic, Inc. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-
 using System;
 using System.Collections.Generic;
 using NewRelic.Agent.IntegrationTestHelpers;
@@ -18,6 +17,8 @@ public class AspNetCoreDistTraceRequestChainFixture : RemoteApplicationFixture
         public RemoteService FirstCallApplication { get; set; }
         public RemoteService SecondCallApplication { get; set; }
 
+        public bool ExcludeNewRelicHeader = false;
+
         private AgentLogFile _firstCallAppAgentLog;
         private AgentLogFile _secondCallAppAgentLog;
 
@@ -42,8 +43,8 @@ public AspNetCoreDistTraceRequestChainFixture()
                 configModifier.SetLogLevel("all");
 
                 //Do during setup so TestLogger is set.
-                FirstCallApplication = SetupDistributedTracingApplication();
-                SecondCallApplication = SetupDistributedTracingApplication();
+                FirstCallApplication = SetupDistributedTracingApplication(ExcludeNewRelicHeader);
+                SecondCallApplication = SetupDistributedTracingApplication(ExcludeNewRelicHeader);
 
                 var environmentVariables = new Dictionary<string, string>();
 
@@ -74,7 +75,7 @@ public void ExecuteTraceRequestChain(string firstAppAction, string secondAppActi
             }
         }
 
-        protected RemoteService SetupDistributedTracingApplication()
+        protected RemoteService SetupDistributedTracingApplication(bool excludeNewRelicHeader)
         {
             var service = new RemoteService(
                 ApplicationDirectoryName,
@@ -93,6 +94,7 @@ protected RemoteService SetupDistributedTracingApplication()
             var configModifier = new NewRelicConfigModifier(service.DestinationNewRelicConfigFilePath);
             configModifier.SetOrDeleteDistributedTraceEnabled(true);
             configModifier.SetOrDeleteSpanEventsEnabled(true);
+            configModifier.SetOrDeleteDistributedTraceExcludeNewRelicHeader(excludeNewRelicHeader);
             configModifier.SetLogLevel("all");
 
             return service;