Change exceptions to be more consistent with Grpc.Core

src/Grpc.Net.Client/Internal/GrpcCall.cs

@@ -34,6 +34,8 @@ internal sealed partial class GrpcCall<TRequest, TResponse> : GrpcCall, IDisposa
         where TRequest : class
         where TResponse : class
     {
+        private const string ErrorStartingCallMessage = "Error starting gRPC call.";
+
         private readonly CancellationTokenSource _callCts;
         private readonly TaskCompletionSource<Status> _callTcs;
         private readonly DateTime _deadline;
@@ -249,7 +251,7 @@ private async Task<Metadata> GetResponseHeadersCoreAsync()
             }
             catch (Exception ex)
             {
-                ResolveException(ex, out _, out var resolvedException);
+                ResolveException(ErrorStartingCallMessage, ex, out _, out var resolvedException);
                 throw resolvedException;
             }
         }
@@ -592,7 +594,7 @@ private async Task RunCall(HttpRequestMessage request, TimeSpan? timeout)
                 catch (Exception ex)
                 {
                     Exception resolvedException;
-                    ResolveException(ex, out status, out resolvedException);
+                    ResolveException(ErrorStartingCallMessage, ex, out status, out resolvedException);
 
                     finished = FinishCall(request, diagnosticSourceEnabled, activity, status.Value);
                     _responseTcs?.TrySetException(resolvedException);
@@ -606,7 +608,7 @@ private async Task RunCall(HttpRequestMessage request, TimeSpan? timeout)
             }
         }
 
-        private void ResolveException(Exception ex, [NotNull] out Status? status, out Exception resolvedException)
+        internal void ResolveException(string summary, Exception ex, [NotNull] out Status? status, out Exception resolvedException)
         {
             if (ex is OperationCanceledException)
             {
@@ -621,8 +623,9 @@ private void ResolveException(Exception ex, [NotNull] out Status? status, out Ex
             else
             {
                 var exceptionMessage = CommonGrpcProtocolHelpers.ConvertToRpcExceptionMessage(ex);
+                var statusCode = GrpcProtocolHelpers.ResolveRpcExceptionStatusCode(ex);
 
-                status = new Status(StatusCode.Internal, "Error starting gRPC call. " +  exceptionMessage, ex);
+                status = new Status(statusCode, summary + " " + exceptionMessage, ex);
                 resolvedException = CreateRpcException(status.Value);
             }
         }

src/Grpc.Net.Client/Internal/GrpcProtocolHelpers.cs

@@ -20,9 +20,11 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
+using System.IO;
 using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Headers;
+using System.Net.Sockets;
 using System.Threading.Tasks;
 using Grpc.Core;
 using Grpc.Net.Compression;
@@ -376,5 +378,29 @@ public static bool TryGetStatusCore(HttpResponseHeaders headers, [NotNullWhen(tr
             status = new Status((StatusCode)statusValue, grpcMessage);
             return true;
         }
+
+        public static StatusCode ResolveRpcExceptionStatusCode(Exception ex)
+        {
+            var current = ex;
+            do
+            {
+                // Grpc.Core tends to return Unavailable if there is a problem establishing the connection.
+                // Additional changes here are likely required for cases when Unavailable is being returned
+                // when it shouldn't be.
+                if (current is SocketException)
+                {
+                    // SocketError.ConnectionRefused happens when port is not available.
+                    // SocketError.HostNotFound happens when unknown host is specified.
+                    return StatusCode.Unavailable;
+                }
+                else if (current is IOException)
+                {
+                    // IOException happens if there is a protocol mismatch.
+                    return StatusCode.Unavailable;
+                }
+            } while ((current = current.InnerException) != null);
+
+            return StatusCode.Internal;
+        }
     }
 }

src/Grpc.Net.Client/Internal/HttpContentClientStreamReader.cs

@@ -195,6 +195,12 @@ private async Task<bool> MoveNextCore(CancellationToken cancellationToken)
 
                 throw _call.CreateCanceledStatusException();
             }
+            catch (Exception ex)
+            {
+                // Throw RpcException from MoveNext. Consistent with Grpc.Core.
+                _call.ResolveException("Error reading next message.", ex, out _, out var resolvedException);
+                throw resolvedException;
+            }
             finally
             {
                 ctsRegistration?.Dispose();

test/Grpc.Net.Client.Tests/ConnectionTests.cs

@@ -17,7 +17,10 @@
 #endregion
 
 using System;
+using System.IO;
 using System.Net;
+using System.Net.Http;
+using System.Net.Sockets;
 using System.Threading.Tasks;
 using Greet;
 using Grpc.Core;
@@ -50,5 +53,44 @@ public async Task UnaryCall_Http1Response_ThrowError()
             Assert.AreEqual(StatusCode.Internal, ex.StatusCode);
             Assert.AreEqual("Bad gRPC response. Response protocol downgraded to HTTP/1.1.", ex.Status.Detail);
         }
+
+        [TestCase(SocketError.HostNotFound, StatusCode.Unavailable)]
+        [TestCase(SocketError.ConnectionRefused, StatusCode.Unavailable)]
+        public async Task UnaryCall_SocketException_ThrowCorrectStatus(SocketError socketError, StatusCode statusCode)
+        {
+            // Arrange
+            var httpClient = ClientTestHelpers.CreateTestClient(request =>
+            {
+                return Task.FromException<HttpResponseMessage>(new HttpRequestException("Blah", new SocketException((int)socketError)));
+            });
+            var invoker = HttpClientCallInvokerFactory.Create(httpClient);
+
+            // Act
+            var call = invoker.AsyncUnaryCall<HelloRequest, HelloReply>(ClientTestHelpers.ServiceMethod, string.Empty, new CallOptions(deadline: invoker.Channel.Clock.UtcNow.AddSeconds(1)), new HelloRequest());
+
+            // Assert
+            var ex = await ExceptionAssert.ThrowsAsync<RpcException>(() => call.ResponseAsync).DefaultTimeout();
+
+            Assert.AreEqual(statusCode, ex.StatusCode);
+        }
+
+        [Test]
+        public async Task UnaryCall_IOException_ThrowCorrectStatus()
+        {
+            // Arrange
+            var httpClient = ClientTestHelpers.CreateTestClient(request =>
+            {
+                return Task.FromException<HttpResponseMessage>(new HttpRequestException("Blah", new IOException("")));
+            });
+            var invoker = HttpClientCallInvokerFactory.Create(httpClient);
+
+            // Act
+            var call = invoker.AsyncUnaryCall<HelloRequest, HelloReply>(ClientTestHelpers.ServiceMethod, string.Empty, new CallOptions(deadline: invoker.Channel.Clock.UtcNow.AddSeconds(1)), new HelloRequest());
+
+            // Assert
+            var ex = await ExceptionAssert.ThrowsAsync<RpcException>(() => call.ResponseAsync).DefaultTimeout();
+
+            Assert.AreEqual(StatusCode.Unavailable, ex.StatusCode);
+        }
     }
 }

test/Grpc.Net.Client.Tests/HttpContentClientStreamReaderTests.cs

@@ -17,6 +17,7 @@
 #endregion
 
 using System;
+using System.IO;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
@@ -201,6 +202,32 @@ public async Task MoveNext_MultipleCallsWithoutAwait_ThrowError()
             Assert.AreEqual(ex, write.Exception);
         }
 
+        [Test]
+        public async Task MoveNext_StreamThrowsIOException_ThrowErrorUnavailable()
+        {
+            // Arrange
+            var httpClient = ClientTestHelpers.CreateTestClient(request =>
+            {
+                var stream = new TestStream();
+                var content = new StreamContent(stream);
+                return Task.FromResult(ResponseUtils.CreateResponse(HttpStatusCode.OK, content));
+            });
+
+            var testSink = new TestSink(e => e.LogLevel >= LogLevel.Error);
+            var testLoggerFactory = new TestLoggerFactory(testSink, enabled: true);
+
+            var channel = CreateChannel(httpClient, loggerFactory: testLoggerFactory);
+            var call = CreateGrpcCall(channel);
+            call.StartServerStreaming(new HelloRequest());
+
+            // Act
+            var ex = await ExceptionAssert.ThrowsAsync<RpcException>(() => call.ClientStreamReader!.MoveNext(CancellationToken.None)).DefaultTimeout();
+
+            // Assert
+            Assert.AreEqual(StatusCode.Unavailable, ex.StatusCode);
+            Assert.AreEqual("Error reading next message. IOException: Test", ex.Status.Detail);
+        }
+
         private static GrpcCall<HelloRequest, HelloReply> CreateGrpcCall(GrpcChannel channel)
         {
             var uri = new Uri("http://localhost");
@@ -223,5 +250,44 @@ private static GrpcChannel CreateChannel(HttpClient httpClient, ILoggerFactory?
                     ThrowOperationCanceledOnCancellation = throwOperationCanceledOnCancellation ?? false
                 });
         }
+
+        private class TestStream : Stream
+        {
+            public override bool CanRead { get; }
+            public override bool CanSeek { get; }
+            public override bool CanWrite { get; }
+            public override long Length { get; }
+            public override long Position { get; set; }
+
+            public override void Flush()
+            {
+                throw new NotImplementedException();
+            }
+
+            public override int Read(byte[] buffer, int offset, int count)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override long Seek(long offset, SeekOrigin origin)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override void SetLength(long value)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override void Write(byte[] buffer, int offset, int count)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+            {
+                return new ValueTask<int>(Task.FromException<int>(new IOException("Test")));
+            }
+        }
     }
 }