Read the ClientRequestId off initial request

sdk/core/Azure.Core/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 1.3.0-preview.1 (Unreleased)
 
+- Read client request ID value used for logging and tracing off the initial request object if available.
 
 ## 1.2.0 (2020-04-03)
 

sdk/core/Azure.Core/src/Pipeline/HttpClientTransport.cs

@@ -170,11 +170,11 @@ private sealed class PipelineRequest : Request
             private readonly HttpRequestMessage _requestMessage;
 
             private PipelineContentAdapter? _requestContent;
+            private string? _clientRequestId;
 
             public PipelineRequest()
             {
                 _requestMessage = new HttpRequestMessage();
-                ClientRequestId = Guid.NewGuid().ToString();
             }
 
             public override RequestMethod Method
@@ -185,7 +185,11 @@ public override RequestMethod Method
 
             public override RequestContent? Content { get; set; }
 
-            public override string ClientRequestId { get; set; }
+            public override string ClientRequestId
+            {
+                get => _clientRequestId ??= Guid.NewGuid().ToString();
+                set => _clientRequestId = value;
+            }
 
             protected internal override void AddHeader(string name, string value)
             {

sdk/core/Azure.Core/src/Pipeline/HttpPipelineBuilder.cs

@@ -48,12 +48,12 @@ public static HttpPipeline Build(ClientOptions options, HttpPipelinePolicy[] per
 
             bool isDistributedTracingEnabled = options.Diagnostics.IsDistributedTracingEnabled;
 
+            policies.Add(ClientRequestIdPolicy.Shared);
+
             policies.AddRange(perCallPolicies);
 
             policies.AddRange(options.PerCallPolicies);
 
-            policies.Add(ClientRequestIdPolicy.Shared);
-
             DiagnosticsOptions diagnostics = options.Diagnostics;
             if (diagnostics.IsTelemetryEnabled)
             {

sdk/core/Azure.Core/src/Pipeline/Internal/ClientRequestIdPolicy.cs

@@ -16,7 +16,14 @@ protected ClientRequestIdPolicy()
 
         public override void OnSendingRequest(HttpMessage message)
         {
-            message.Request.Headers.Add(ClientRequestIdHeader, message.Request.ClientRequestId);
+            if (message.Request.Headers.TryGetValue(ClientRequestIdHeader, out string? value))
+            {
+                message.Request.ClientRequestId = value;
+            }
+            else
+            {
+                message.Request.Headers.Add(ClientRequestIdHeader, message.Request.ClientRequestId);
+            }
             message.Request.Headers.Add(EchoClientRequestId, "true");
         }
     }

sdk/core/Azure.Core/tests/ClientRequestIdPolicyTests.cs

@@ -1,9 +1,12 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System;
+using System.Threading;
 using System.Threading.Tasks;
 using Azure.Core.Pipeline;
 using Azure.Core.Testing;
+using Moq;
 using NUnit.Framework;
 
 namespace Azure.Core.Tests
@@ -23,5 +26,32 @@ public async Task SetsHeaders()
             Assert.AreEqual(request.ClientRequestId, requestId);
             Assert.AreEqual("true", returnRequestId);
         }
+
+        [Test]
+        public async Task ReadsRequestIdValueOfRequest()
+        {
+            var policy = new Mock<HttpPipelineSynchronousPolicy>();
+            policy.CallBase = true;
+            policy.Setup(p => p.OnReceivedResponse(It.IsAny<HttpMessage>()))
+                .Callback<HttpMessage>(message =>
+                {
+                    Assert.AreEqual("ExternalClientId",message.Request.ClientRequestId);
+                    Assert.True(message.Request.TryGetHeader("x-ms-client-request-id", out string requestId));
+                    Assert.AreEqual("ExternalClientId", requestId);
+                }).Verifiable();
+
+            var transport = new MockTransport(new MockResponse(200));
+            var pipeline = new HttpPipeline(transport, new[] { ClientRequestIdPolicy.Shared, policy.Object });
+
+            using (Request request = pipeline.CreateRequest())
+            {
+                request.Method = RequestMethod.Get;
+                request.Uri.Reset(new Uri("http://example.com"));
+                request.Headers.Add("x-ms-client-request-id", "ExternalClientId");
+                await pipeline.SendRequestAsync(request, CancellationToken.None);
+            }
+
+            policy.Verify();
+        }
     }
 }

sdk/core/Azure.Core/tests/HttpPipelineBuilderTest.cs

@@ -9,6 +9,7 @@
 using System.Threading.Tasks;
 using Azure.Core.Pipeline;
 using Azure.Core.Testing;
+using Moq;
 using NUnit.Framework;
 
 namespace Azure.Core.Tests
@@ -77,6 +78,35 @@ public async Task VersionDoesntHaveCommitHash()
                                  Regex.Escape($" ({RuntimeInformation.FrameworkDescription}; {RuntimeInformation.OSDescription})"), userAgent);
         }
 
+        [Test]
+        public async Task CustomClientRequestIdAvailableInPerCallPolicies()
+        {
+            var policy = new Mock<HttpPipelineSynchronousPolicy>();
+            policy.CallBase = true;
+            policy.Setup(p => p.OnReceivedResponse(It.IsAny<HttpMessage>()))
+                .Callback<HttpMessage>(message =>
+                {
+                    Assert.AreEqual("ExternalClientId",message.Request.ClientRequestId);
+                    Assert.True(message.Request.TryGetHeader("x-ms-client-request-id", out string requestId));
+                    Assert.AreEqual("ExternalClientId", requestId);
+                }).Verifiable();
+
+            var options = new TestOptions();
+            options.Transport = new MockTransport(new MockResponse(200));
+            options.AddPolicy(policy.Object, HttpPipelinePosition.PerCall);
+
+            var pipeline = HttpPipelineBuilder.Build(options);
+            using (Request request = pipeline.CreateRequest())
+            {
+                request.Method = RequestMethod.Get;
+                request.Uri.Reset(new Uri("http://example.com"));
+                request.Headers.Add("x-ms-client-request-id", "ExternalClientId");
+                await pipeline.SendRequestAsync(request, CancellationToken.None);
+            }
+
+            policy.Verify();
+        }
+
         private class TestOptions : ClientOptions
         {
             public TestOptions()