Error reason not propagating on some status codes

Microsoft.Azure.Cosmos/src/GatewayStoreClient.cs

@@ -81,20 +81,16 @@ internal static async Task<DocumentServiceResponse> ParseResponseAsync(HttpRespo
             {
                 if ((int)responseMessage.StatusCode < 400)
                 {
-                    MemoryStream bufferedStream = new MemoryStream();
-
-                    await responseMessage.Content.CopyToAsync(bufferedStream);
-
-                    bufferedStream.Position = 0;
-
                     INameValueCollection headers = GatewayStoreClient.ExtractResponseHeaders(responseMessage);
-                    return new DocumentServiceResponse(bufferedStream, headers, responseMessage.StatusCode, serializerSettings);
+                    Stream contentStream = await GatewayStoreClient.BufferContentIfAvailableAsync(responseMessage);
+                    return new DocumentServiceResponse(contentStream, headers, responseMessage.StatusCode, serializerSettings);
                 }
                 else if (request != null
                     && request.IsValidStatusCodeForExceptionlessRetry((int)responseMessage.StatusCode))
                 {
                     INameValueCollection headers = GatewayStoreClient.ExtractResponseHeaders(responseMessage);
-                    return new DocumentServiceResponse(null, headers, responseMessage.StatusCode, serializerSettings);
+                    Stream contentStream = await GatewayStoreClient.BufferContentIfAvailableAsync(responseMessage);
+                    return new DocumentServiceResponse(contentStream, headers, responseMessage.StatusCode, serializerSettings);
                 }
                 else
                 {
@@ -225,6 +221,19 @@ internal static bool IsAllowedRequestHeader(string headerName)
             return true;
         }
 
+        private static async Task<Stream> BufferContentIfAvailableAsync(HttpResponseMessage responseMessage)
+        {
+            if (responseMessage.Content == null)
+            {
+                return null;
+            }
+
+            MemoryStream bufferedStream = new MemoryStream();
+            await responseMessage.Content.CopyToAsync(bufferedStream);
+            bufferedStream.Position = 0;
+            return bufferedStream;
+        }
+
         [SuppressMessage("Microsoft.Reliability", "CA2000:DisposeObjectsBeforeLosingScope", Justification = "Disposable object returned by method")]
         private async Task<HttpRequestMessage> PrepareRequestMessageAsync(
             DocumentServiceRequest request,

Microsoft.Azure.Cosmos/src/Handler/ResponseMessage.cs

@@ -136,6 +136,7 @@ public virtual ResponseMessage EnsureSuccessStatusCode()
         {
             if (!this.IsSuccessStatusCode)
             {
+                this.EnsureErrorMessage();
                 string message = $"Response status code does not indicate success: {(int)this.StatusCode} Substatus: {(int)this.Headers.SubStatusCode} Reason: ({this.ErrorMessage}).";
 
                 throw new CosmosException(
@@ -202,5 +203,44 @@ private void CheckDisposed()
                 throw new ObjectDisposedException(this.GetType().ToString());
             }
         }
+
+        private void EnsureErrorMessage()
+        {
+            if (this.Error != null
+                || !string.IsNullOrEmpty(this.ErrorMessage))
+            {
+                return;
+            }
+
+            if (this.content != null
+                && this.content.CanRead)
+            {
+                try
+                {
+                    Error error = Resource.LoadFrom<Error>(this.content);
+                    if (error != null)
+                    {
+                        // Error format is not consistent across modes
+                        if (!string.IsNullOrEmpty(error.Message))
+                        {
+                            this.ErrorMessage = error.Message;
+                        }
+                        else
+                        {
+                            this.ErrorMessage = error.ToString();
+                        }
+                    }
+                }
+                catch (Newtonsoft.Json.JsonReaderException)
+                {
+                    // Content is not Json
+                    this.content.Position = 0;
+                    using (StreamReader streamReader = new StreamReader(this.content))
+                    {
+                        this.ErrorMessage = streamReader.ReadToEnd();
+                    }
+                }
+            }
+        }
     }
 }

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/CosmosExceptionTests.cs

@@ -0,0 +1,90 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+
+namespace Microsoft.Azure.Cosmos
+{
+    using System;
+    using System.IO;
+    using System.Net;
+    using System.Net.Http;
+    using System.Text;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.Azure.Cosmos.Common;
+    using Microsoft.Azure.Cosmos.Routing;
+    using Microsoft.Azure.Documents;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+    using Moq;
+    using Newtonsoft.Json;
+
+    [TestClass]
+    public class CosmosExceptionTests
+    {
+        [TestMethod]
+        public void EnsureSuccessStatusCode_DontThrowOnSuccess()
+        {
+            ResponseMessage responseMessage = new ResponseMessage(HttpStatusCode.OK);
+            responseMessage.EnsureSuccessStatusCode();
+        }
+
+        [TestMethod]
+        public void EnsureSuccessStatusCode_ThrowsOnFailure()
+        {
+            ResponseMessage responseMessage = new ResponseMessage(HttpStatusCode.NotFound);
+            Assert.ThrowsException<CosmosException>(() => responseMessage.EnsureSuccessStatusCode());
+        }
+
+        [TestMethod]
+        public void EnsureSuccessStatusCode_ThrowsOnFailure_ContainsBody()
+        {
+            string testContent = "TestContent";
+            using (MemoryStream memoryStream = new MemoryStream())
+            {
+                StreamWriter sw = new StreamWriter(memoryStream);
+                sw.Write(testContent);
+                sw.Flush();
+                memoryStream.Seek(0, SeekOrigin.Begin);
+
+                ResponseMessage responseMessage = new ResponseMessage(HttpStatusCode.NotFound) { Content = memoryStream };
+                try
+                {
+                    responseMessage.EnsureSuccessStatusCode();
+                    Assert.Fail("Should have thrown");
+                }
+                catch(CosmosException exception)
+                {
+                    Assert.IsTrue(exception.Message.Contains(testContent));
+                }
+            }
+        }
+
+        [TestMethod]
+        public void EnsureSuccessStatusCode_ThrowsOnFailure_ContainsJsonBody()
+        {
+            string message = "TestContent";
+            Error error = new Error();
+            error.Code = "code";
+            error.Message = message;
+            string testContent = JsonConvert.SerializeObject(error);
+            using (MemoryStream memoryStream = new MemoryStream())
+            {
+                StreamWriter sw = new StreamWriter(memoryStream);
+                sw.Write(testContent);
+                sw.Flush();
+                memoryStream.Seek(0, SeekOrigin.Begin);
+
+                ResponseMessage responseMessage = new ResponseMessage(HttpStatusCode.NotFound) { Content = memoryStream };
+                try
+                {
+                    responseMessage.EnsureSuccessStatusCode();
+                    Assert.Fail("Should have thrown");
+                }
+                catch (CosmosException exception)
+                {
+                    Assert.IsTrue(exception.Message.Contains(message));
+                }
+            }
+        }
+    }
+}

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/GatewayStoreModelTest.cs

@@ -148,6 +148,58 @@ public async Task TestRetries()
 
         }
 
+        [TestMethod]
+        public async Task TestErrorResponsesProvideBody()
+        {
+            string testContent = "Content";
+            Func<HttpRequestMessage, Task<HttpResponseMessage>> sendFunc = async request =>
+            {
+                return new HttpResponseMessage(HttpStatusCode.Conflict) { Content = new StringContent(testContent) };
+            };
+
+            Mock<IDocumentClientInternal> mockDocumentClient = new Mock<IDocumentClientInternal>();
+            mockDocumentClient.Setup(client => client.ServiceEndpoint).Returns(new Uri("https://foo"));
+
+            GlobalEndpointManager endpointManager = new GlobalEndpointManager(mockDocumentClient.Object, new ConnectionPolicy());
+            ISessionContainer sessionContainer = new SessionContainer(string.Empty);
+            DocumentClientEventSource eventSource = DocumentClientEventSource.Instance;
+            HttpMessageHandler messageHandler = new MockMessageHandler(sendFunc);
+            GatewayStoreModel storeModel = new GatewayStoreModel(
+                endpointManager,
+                sessionContainer,
+                TimeSpan.FromSeconds(5),
+                ConsistencyLevel.Eventual,
+                eventSource,
+                null,
+                new UserAgentContainer(),
+                ApiType.None,
+                messageHandler);
+
+            using (new ActivityScope(Guid.NewGuid()))
+            {
+                using (DocumentServiceRequest request =
+                DocumentServiceRequest.Create(
+                    Documents.OperationType.Query,
+                    Documents.ResourceType.Document,
+                    new Uri("https://foo.com/dbs/db1/colls/coll1", UriKind.Absolute),
+                    new MemoryStream(Encoding.UTF8.GetBytes("content1")),
+                    AuthorizationTokenType.PrimaryMasterKey,
+                    null))
+                {
+                    request.UseStatusCodeForFailures = true;
+                    request.UseStatusCodeFor429 = true;
+
+                    DocumentServiceResponse response = await storeModel.ProcessMessageAsync(request);
+                    Assert.IsNotNull(response.ResponseBody);
+                    using (StreamReader reader = new StreamReader(response.ResponseBody))
+                    {
+                        Assert.AreEqual(testContent, await reader.ReadToEndAsync());
+                    }
+                }
+            }
+
+        }
+
         /// <summary>
         /// Tests that empty session token is sent for operations on Session Consistent resources like
         /// Databases, Collections, Users, Permissions, PartitionKeyRanges, DatabaseAccounts and Offers

changelog.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - [#726](https://github.com/Azure/azure-cosmos-dotnet-v3/pull/726) Query iterator HasMoreResults now returns false if an exception is hit
 - [#705](https://github.com/Azure/azure-cosmos-dotnet-v3/pull/705) User agent suffix gets truncated
+- [#753](https://github.com/Azure/azure-cosmos-dotnet-v3/pull/753) Reason was not being propagated for Conflict exceptions
 - [#756](https://github.com/Azure/azure-cosmos-dotnet-v3/pull/756) Change Feed Processor with WithStartTime would execute the delegate the first time with no items.
 
 ## [3.1.1](https://www.nuget.org/packages/Microsoft.Azure.Cosmos/3.1.1) - 2019-08-12