Added basic support for cancellation

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -47,23 +47,59 @@ namespace Grpc.Core.Tests
         const string Host = "localhost";
         const string ServiceName = "/tests.Test";
 
-        static readonly Method<string, string> UnaryEchoStringMethod = new Method<string, string>(
+        static readonly Method<string, string> EchoMethod = new Method<string, string>(
             MethodType.Unary,
-            "/tests.Test/UnaryEchoString",
+            "/tests.Test/Echo",
+            Marshallers.StringMarshaller,
+            Marshallers.StringMarshaller);
+
+        static readonly Method<string, string> ConcatAndEchoMethod = new Method<string, string>(
+            MethodType.ClientStreaming,
+            "/tests.Test/ConcatAndEcho",
+            Marshallers.StringMarshaller,
+            Marshallers.StringMarshaller);
+
+        static readonly Method<string, string> NonexistentMethod = new Method<string, string>(
+            MethodType.Unary,
+            "/tests.Test/NonexistentMethod",
             Marshallers.StringMarshaller,
             Marshallers.StringMarshaller);
 
         static readonly ServerServiceDefinition ServiceDefinition = ServerServiceDefinition.CreateBuilder(ServiceName)
-            .AddMethod(UnaryEchoStringMethod, HandleUnaryEchoString).Build();
+            .AddMethod(EchoMethod, EchoHandler)
+            .AddMethod(ConcatAndEchoMethod, ConcatAndEchoHandler)
+            .Build();
+
+        Server server;
+        Channel channel;
 
         [TestFixtureSetUp]
+        public void InitClass()
+        {
+            GrpcEnvironment.Initialize();
+        }
+
+        [SetUp]
         public void Init()
         {
             GrpcEnvironment.Initialize();
+
+            server = new Server();
+            server.AddServiceDefinition(ServiceDefinition);
+            int port = server.AddListeningPort(Host + ":0");
+            server.Start();
+            channel = new Channel(Host + ":" + port);
         }
 
-        [TestFixtureTearDown]
+        [TearDown]
         public void Cleanup()
+        {
+            channel.Dispose();
+            server.ShutdownAsync().Wait();
+        }
+
+        [TestFixtureTearDown]
+        public void CleanupClass()
         {
             GrpcEnvironment.Shutdown();
         }
@@ -71,93 +107,160 @@ namespace Grpc.Core.Tests
         [Test]
         public void UnaryCall()
         {
-            var server = new Server();
-            server.AddServiceDefinition(ServiceDefinition);
-            int port = server.AddListeningPort(Host + ":0");
-            server.Start();
-
-            using (Channel channel = new Channel(Host + ":" + port))
-            {
-                var call = new Call<string, string>(ServiceName, UnaryEchoStringMethod, channel, Metadata.Empty);
-                Assert.AreEqual("ABC", Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken)));
-            }
-
-            server.ShutdownAsync().Wait();
+            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            Assert.AreEqual("ABC", Calls.BlockingUnaryCall(call, "ABC", CancellationToken.None));
         }
 
         [Test]
-        public void CallOnDisposedChannel()
+        public void UnaryCall_ServerHandlerThrows()
         {
-            var server = new Server();
-            server.AddServiceDefinition(ServiceDefinition);
-            int port = server.AddListeningPort(Host + ":0");
-            server.Start();
-
-            Channel channel = new Channel(Host + ":" + port);
-            channel.Dispose();
-
-            var call = new Call<string, string>(ServiceName, UnaryEchoStringMethod, channel, Metadata.Empty);
+            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
             try
             {
-              Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken));
-              Assert.Fail();
+                Calls.BlockingUnaryCall(call, "THROW", CancellationToken.None);
+                Assert.Fail();
             }
-            catch (ObjectDisposedException e)
+            catch (RpcException e)
             {
+                Assert.AreEqual(StatusCode.Unknown, e.Status.StatusCode); 
             }
+        }
 
-            server.ShutdownAsync().Wait();
+        [Test]
+        public void AsyncUnaryCall()
+        {
+            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            var result = Calls.AsyncUnaryCall(call, "ABC", CancellationToken.None).Result;
+            Assert.AreEqual("ABC", result);
         }
 
         [Test]
-        public void UnaryCallPerformance()
+        public void AsyncUnaryCall_ServerHandlerThrows()
         {
-            var server = new Server();
-            server.AddServiceDefinition(ServiceDefinition);
-            int port = server.AddListeningPort(Host + ":0");
-            server.Start();
+            Task.Run(async () => 
+            {
+                var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+                try
+                {
+                    await Calls.AsyncUnaryCall(call, "THROW", CancellationToken.None);
+                    Assert.Fail();
+                }
+                catch (RpcException e)
+                {
+                    Assert.AreEqual(StatusCode.Unknown, e.Status.StatusCode); 
+                }
+            }).Wait();
+        }
 
-            using (Channel channel = new Channel(Host + ":" + port))
+        [Test]
+        public void ClientStreamingCall()
+        {
+            Task.Run(async () => 
             {
-                var call = new Call<string, string>(ServiceName, UnaryEchoStringMethod, channel, Metadata.Empty);
-                BenchmarkUtil.RunBenchmark(100, 100,
-                                           () => { Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken)); });
-            }
+                var call = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
+                var callResult = Calls.AsyncClientStreamingCall(call, CancellationToken.None);
 
-            server.ShutdownAsync().Wait();
+                await callResult.RequestStream.WriteAll(new string[] { "A", "B", "C" });
+                Assert.AreEqual("ABC", await callResult.Result);
+            }).Wait();
         }
 
         [Test]
-        public void UnknownMethodHandler()
+        public void ClientStreamingCall_ServerHandlerThrows()
         {
-            var server = new Server();
-            server.AddServiceDefinition(ServerServiceDefinition.CreateBuilder(ServiceName).Build());
-            int port = server.AddListeningPort(Host + ":0");
-            server.Start();
+            Task.Run(async () => 
+                     {
+                var call = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
+                var callResult = Calls.AsyncClientStreamingCall(call, CancellationToken.None);
+                // TODO(jtattermusch): if we send "A", "THROW", "C", server hangs.
+                await callResult.RequestStream.WriteAll(new string[] { "A", "B", "THROW" });
+
+                try
+                {
+                    await callResult.Result;
+                }
+                catch(RpcException e)
+                {
+                    Assert.AreEqual(StatusCode.Unknown, e.Status.StatusCode); 
+                }
+            }).Wait();
+        }
 
-            using (Channel channel = new Channel(Host + ":" + port))
+        [Test]
+        public void ClientStreamingCall_CancelAfterBegin()
+        {
+            Task.Run(async () => 
             {
-                var call = new Call<string, string>(ServiceName, UnaryEchoStringMethod, channel, Metadata.Empty);
+                var call = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
+
+                var cts = new CancellationTokenSource();
+                var callResult = Calls.AsyncClientStreamingCall(call, cts.Token);
+                cts.Cancel();
+
                 try
                 {
-                    Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken));
-                    Assert.Fail();
+                    await callResult.Result;
                 }
-                catch (RpcException e)
+                catch(RpcException e)
                 {
-                    Assert.AreEqual(StatusCode.Unimplemented, e.Status.StatusCode);
+                    Assert.AreEqual(StatusCode.Cancelled, e.Status.StatusCode); 
                 }
+            }).Wait();
+        }
+
+        [Test]
+        public void UnaryCall_DisposedChannel()
+        {
+            channel.Dispose();
+
+            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            Assert.Throws(typeof(ObjectDisposedException), () => Calls.BlockingUnaryCall(call, "ABC", CancellationToken.None));
+        }
+
+        [Test]
+        public void UnaryCallPerformance()
+        {
+            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            BenchmarkUtil.RunBenchmark(100, 100,
+                                       () => { Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken)); });
+        }
+
+        [Test]
+        public void UnknownMethodHandler()
+        {
+            var call = new Call<string, string>(ServiceName, NonexistentMethod, channel, Metadata.Empty);
+            try
+            {
+                Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken));
+                Assert.Fail();
+            }
+            catch (RpcException e)
+            {
+                Assert.AreEqual(StatusCode.Unimplemented, e.Status.StatusCode);
             }
+        }
 
-            server.ShutdownAsync().Wait();
+        private static async Task<string> EchoHandler(string request)
+        {
+            if (request == "THROW")
+            {
+                throw new Exception("This was thrown on purpose by a test");
+            }
+            return request;
         }
 
-        /// <summary>
-        /// Handler for unaryEchoString method.
-        /// </summary>
-        private static Task<string> HandleUnaryEchoString(string request)
+        private static async Task<string> ConcatAndEchoHandler(IAsyncStreamReader<string> requestStream)
         {
-            return Task.FromResult(request);
+            string result = "";
+            await requestStream.ForEach(async (request) =>
+            {
+                if (request == "THROW")
+                {
+                    throw new Exception("This was thrown on purpose by a test");
+                }
+                result += request;
+            });
+            return result;   
         }
     }
 }

src/csharp/Grpc.Core/Calls.cs

@@ -46,6 +46,8 @@ namespace Grpc.Core
         public static TResponse BlockingUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
+            // TODO(jtattermusch): this gives a race that cancellation can be requested before the call even starts.
+            RegisterCancellationCallback(asyncCall, token);
             return asyncCall.UnaryCall(call.Channel, call.Name, req, call.Headers);
         }
 
@@ -53,7 +55,9 @@ namespace Grpc.Core
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
-            return await asyncCall.UnaryCallAsync(req, call.Headers);
+            var asyncResult = asyncCall.UnaryCallAsync(req, call.Headers);
+            RegisterCancellationCallback(asyncCall, token);
+            return await asyncResult;
         }
 
         public static AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
@@ -61,6 +65,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
             asyncCall.StartServerStreamingCall(req, call.Headers);
+            RegisterCancellationCallback(asyncCall, token);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
             return new AsyncServerStreamingCall<TResponse>(responseStream);
         }
@@ -70,6 +75,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
             var resultTask = asyncCall.ClientStreamingCallAsync(call.Headers);
+            RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask);
         }
@@ -79,11 +85,20 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
             asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
             asyncCall.StartDuplexStreamingCall(call.Headers);
+            RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
             return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream);
         }
 
+        private static void RegisterCancellationCallback<TRequest, TResponse>(AsyncCall<TRequest, TResponse> asyncCall, CancellationToken token)
+        {
+            if (token.CanBeCanceled)
+            {
+                token.Register( () => asyncCall.Cancel() );
+            }
+        }
+
         /// <summary>
         /// Gets shared completion queue used for async calls.
         /// </summary>

src/csharp/Grpc.Core/Internal/AsyncCallServer.cs

@@ -121,6 +121,12 @@ namespace Grpc.Core.Internal
             {
                 finished = true;
 
+                if (readCompletionDelegate == null)
+                {
+                    // allow disposal of native call
+                    readingDone = true;
+                }
+
                 ReleaseResourcesIfPossible();
             }
             // TODO: handle error ...

src/csharp/Grpc.Core/Internal/ServerCallHandler.cs

@@ -66,13 +66,21 @@ namespace Grpc.Core.Internal
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
-            var request = await requestStream.ReadNext();
-            // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
-            Preconditions.CheckArgument(await requestStream.ReadNext() == null);
-
-            var result = await handler(request);
-            await responseStream.Write(result);
-            await responseStream.WriteStatus(Status.DefaultSuccess);
+            Status status = Status.DefaultSuccess;
+            try
+            {
+                var request = await requestStream.ReadNext();
+                // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
+                Preconditions.CheckArgument(await requestStream.ReadNext() == null);
+                var result = await handler(request);
+                await responseStream.Write(result);
+            } 
+            catch (Exception e)
+            {
+                Console.WriteLine("Exception occured in handler: " + e);
+                status = HandlerUtils.StatusFromException(e);
+            }
+            await responseStream.WriteStatus(status);
             await finishedTask;
         }
     }
@@ -99,12 +107,21 @@ namespace Grpc.Core.Internal
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
-            var request = await requestStream.ReadNext();
-            // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
-            Preconditions.CheckArgument(await requestStream.ReadNext() == null);
-
-            await handler(request, responseStream);
-            await responseStream.WriteStatus(Status.DefaultSuccess);
+            Status status = Status.DefaultSuccess;
+            try
+            {
+                var request = await requestStream.ReadNext();
+                // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
+                Preconditions.CheckArgument(await requestStream.ReadNext() == null);
+
+                await handler(request, responseStream);
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine("Exception occured in handler: " + e);
+                status = HandlerUtils.StatusFromException(e);
+            }
+            await responseStream.WriteStatus(status);
             await finishedTask;
         }
     }
@@ -131,9 +148,18 @@ namespace Grpc.Core.Internal
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
-            var result = await handler(requestStream);
-            await responseStream.Write(result);
-            await responseStream.WriteStatus(Status.DefaultSuccess);
+            Status status = Status.DefaultSuccess;
+            try
+            {
+              var result = await handler(requestStream);
+              await responseStream.Write(result);
+            } 
+            catch (Exception e)
+            {
+                Console.WriteLine("Exception occured in handler: " + e);
+                status = HandlerUtils.StatusFromException(e);
+            }
+            await responseStream.WriteStatus(status);
             await finishedTask;
         }
     }
@@ -160,8 +186,17 @@ namespace Grpc.Core.Internal
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
-            await handler(requestStream, responseStream);
-            await responseStream.WriteStatus(Status.DefaultSuccess);
+            Status status = Status.DefaultSuccess;
+            try
+            {
+                await handler(requestStream, responseStream);
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine("Exception occured in handler: " + e);
+                status = HandlerUtils.StatusFromException(e);
+            }
+            await responseStream.WriteStatus(status);
             await finishedTask;
         }
     }
@@ -173,15 +208,25 @@ namespace Grpc.Core.Internal
             // We don't care about the payload type here.
             var asyncCall = new AsyncCallServer<byte[], byte[]>(
                 (payload) => payload, (payload) => payload);
-
+            
             asyncCall.Initialize(call);
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<byte[], byte[]>(asyncCall);
             var responseStream = new ServerResponseStream<byte[], byte[]>(asyncCall);
+
             await responseStream.WriteStatus(new Status(StatusCode.Unimplemented, "No such method."));
             // TODO(jtattermusch): if we don't read what client has sent, the server call never gets disposed.
             await requestStream.ToList();
             await finishedTask;
         }
     }
+
+    internal static class HandlerUtils
+    {
+        public static Status StatusFromException(Exception e)
+        {
+            // TODO(jtattermusch): what is the right status code here?
+            return new Status(StatusCode.Unknown, "Exception was thrown by handler.");
+        }
+    }
 }

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

@@ -34,6 +34,7 @@
 using System;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
+using System.Threading;
 using System.Threading.Tasks;
 
 using Google.ProtocolBuffers;
@@ -166,6 +167,12 @@ namespace Grpc.IntegrationTesting
                 case "compute_engine_creds":
                     RunComputeEngineCreds(client);
                     break;
+                case "cancel_after_begin":
+                    RunCancelAfterBegin(client);
+                    break;
+                case "cancel_after_first_response":
+                    RunCancelAfterFirstResponse(client);
+                    break;
                 case "benchmark_empty_unary":
                     RunBenchmarkEmptyUnary(client);
                     break;
@@ -351,6 +358,64 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("Passed!");
         }
 
+        public static void RunCancelAfterBegin(TestServiceGrpc.ITestServiceClient client)
+        {
+            Task.Run(async () =>
+            {
+                Console.WriteLine("running cancel_after_begin");
+
+                var cts = new CancellationTokenSource();
+                var call = client.StreamingInputCall(cts.Token);
+                cts.Cancel();
+
+                try
+                {
+                    var response = await call.Result;
+                    Assert.Fail();
+                } 
+                catch (RpcException e)
+                {
+                    Assert.AreEqual(StatusCode.Cancelled, e.Status.StatusCode);
+                }
+                Console.WriteLine("Passed!");
+            }).Wait();
+        }
+
+        public static void RunCancelAfterFirstResponse(TestServiceGrpc.ITestServiceClient client)
+        {
+            Task.Run(async () =>
+            {
+                Console.WriteLine("running cancel_after_first_response");
+
+                var cts = new CancellationTokenSource();
+                var call = client.FullDuplexCall(cts.Token);
+
+                StreamingOutputCallResponse response;
+
+                await call.RequestStream.Write(StreamingOutputCallRequest.CreateBuilder()
+                    .SetResponseType(PayloadType.COMPRESSABLE)
+                    .AddResponseParameters(ResponseParameters.CreateBuilder().SetSize(31415))
+                    .SetPayload(CreateZerosPayload(27182)).Build());
+
+                response = await call.ResponseStream.ReadNext();
+                Assert.AreEqual(PayloadType.COMPRESSABLE, response.Payload.Type);
+                Assert.AreEqual(31415, response.Payload.Body.Length);
+
+                cts.Cancel();
+
+                try
+                {
+                    response = await call.ResponseStream.ReadNext();
+                    Assert.Fail();
+                }
+                catch (RpcException e)
+                {
+                    Assert.AreEqual(StatusCode.Cancelled, e.Status.StatusCode);
+                }
+                Console.WriteLine("Passed!");
+            }).Wait();
+        }
+
         // This is not an official interop test, but it's useful.
         public static void RunBenchmarkEmptyUnary(TestServiceGrpc.ITestServiceClient client)
         {

src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

@@ -114,8 +114,16 @@ namespace Grpc.IntegrationTesting
             InteropClient.RunEmptyStream(client);
         }
 
-        // TODO: add cancel_after_begin
+        [Test]
+        public void CancelAfterBegin()
+        {
+            InteropClient.RunCancelAfterBegin(client);
+        }
 
-        // TODO: add cancel_after_first_response
+        [Test]
+        public void CancelAfterFirstResponse()
+        {
+            InteropClient.RunCancelAfterFirstResponse(client);
+        }
     }
 }