Support idle connection timeout with pending sockets

src/Grpc.Net.Client/Balancer/Internal/SocketConnectivitySubchannelTransport.cs

@@ -56,6 +56,7 @@ internal class SocketConnectivitySubchannelTransport : ISubchannelTransport, IDi
     private readonly ILogger _logger;
     private readonly Subchannel _subchannel;
     private readonly TimeSpan _socketPingInterval;
+    private readonly TimeSpan _connectionIdleTimeout;
     private readonly Func<Socket, DnsEndPoint, CancellationToken, ValueTask> _socketConnect;
     private readonly List<ActiveStream> _activeStreams;
     private readonly Timer _socketConnectedTimer;
@@ -64,20 +65,23 @@ internal class SocketConnectivitySubchannelTransport : ISubchannelTransport, IDi
     internal Socket? _initialSocket;
     private BalancerAddress? _initialSocketAddress;
     private List<ReadOnlyMemory<byte>>? _initialSocketData;
+    private DateTime? _initialSocketCreatedTime;
     private bool _disposed;
     private BalancerAddress? _currentAddress;
 
     public SocketConnectivitySubchannelTransport(
         Subchannel subchannel,
         TimeSpan socketPingInterval,
         TimeSpan? connectTimeout,
+        TimeSpan connectionIdleTimeout,
         ILoggerFactory loggerFactory,
         Func<Socket, DnsEndPoint, CancellationToken, ValueTask>? socketConnect)
     {
         _logger = loggerFactory.CreateLogger<SocketConnectivitySubchannelTransport>();
         _subchannel = subchannel;
         _socketPingInterval = socketPingInterval;
         ConnectTimeout = connectTimeout;
+        _connectionIdleTimeout = connectionIdleTimeout;
         _socketConnect = socketConnect ?? OnConnect;
         _activeStreams = new List<ActiveStream>();
         _socketConnectedTimer = NonCapturingTimer.Create(OnCheckSocketConnection, state: null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan);
@@ -125,6 +129,7 @@ private void DisconnectUnsynchronized()
         _initialSocket = null;
         _initialSocketAddress = null;
         _initialSocketData = null;
+        _initialSocketCreatedTime = null;
         _lastEndPointIndex = 0;
         _currentAddress = null;
     }
@@ -162,6 +167,7 @@ public async ValueTask<ConnectResult> TryConnectAsync(ConnectContext context)
                     _initialSocket = socket;
                     _initialSocketAddress = currentAddress;
                     _initialSocketData = null;
+                    _initialSocketCreatedTime = DateTime.UtcNow;
 
                     // Schedule ping. Don't set a periodic interval to avoid any chance of timer causing the target method to run multiple times in paralle.
                     // This could happen because of execution delays (e.g. hitting a debugger breakpoint).
@@ -338,6 +344,7 @@ public async ValueTask<Stream> GetStreamAsync(BalancerAddress address, Cancellat
         Socket? socket = null;
         BalancerAddress? socketAddress = null;
         List<ReadOnlyMemory<byte>>? socketData = null;
+        DateTime? socketCreatedTime = null;
         lock (Lock)
         {
             if (_initialSocket != null)
@@ -347,9 +354,11 @@ public async ValueTask<Stream> GetStreamAsync(BalancerAddress address, Cancellat
                 socket = _initialSocket;
                 socketAddress = _initialSocketAddress;
                 socketData = _initialSocketData;
+                socketCreatedTime = _initialSocketCreatedTime;
                 _initialSocket = null;
                 _initialSocketAddress = null;
                 _initialSocketData = null;
+                _initialSocketCreatedTime = null;
 
                 // Double check the address matches the socket address and only use socket on match.
                 // Not sure if this is possible in practice, but better safe than sorry.
@@ -365,10 +374,23 @@ public async ValueTask<Stream> GetStreamAsync(BalancerAddress address, Cancellat
 
         if (socket != null)
         {
-            if (IsSocketInBadState(socket, address))
+            Debug.Assert(socketCreatedTime != null);
+
+            var closeSocket = false;
+
+            if (DateTime.UtcNow > socketCreatedTime.Value.Add(_connectionIdleTimeout))
+            {
+                SocketConnectivitySubchannelTransportLog.ClosingSocketFromIdleTimeoutOnCreateStream(_logger, _subchannel.Id, address, _connectionIdleTimeout);
+                closeSocket = true;
+            }
+            else if (IsSocketInBadState(socket, address))
             {
                 SocketConnectivitySubchannelTransportLog.ClosingUnusableSocketOnCreateStream(_logger, _subchannel.Id, address);
+                closeSocket = true;
+            }
 
+            if (closeSocket)
+            {
                 socket.Dispose();
                 socket = null;
                 socketData = null;
@@ -530,6 +552,9 @@ internal static class SocketConnectivitySubchannelTransportLog
     private static readonly Action<ILogger, int, BalancerAddress, Exception?> _closingUnusableSocketOnCreateStream =
         LoggerMessage.Define<int, BalancerAddress>(LogLevel.Debug, new EventId(16, "ClosingUnusableSocketOnCreateStream"), "Subchannel id '{SubchannelId}' socket {Address} is being closed because it can't be used. The socket either can't receive data or it has received unexpected data.");
 
+    private static readonly Action<ILogger, int, BalancerAddress, TimeSpan, Exception?> _closingSocketFromIdleTimeoutOnCreateStream =
+        LoggerMessage.Define<int, BalancerAddress, TimeSpan>(LogLevel.Debug, new EventId(16, "ClosingSocketFromIdleTimeoutOnCreateStream"), "Subchannel id '{SubchannelId}' socket {Address} is being closed because it exceeds the idle timeout of {IdleTimeout}.");
+
     public static void ConnectingSocket(ILogger logger, int subchannelId, BalancerAddress address)
     {
         _connectingSocket(logger, subchannelId, address, null);
@@ -609,5 +634,10 @@ public static void ClosingUnusableSocketOnCreateStream(ILogger logger, int subch
     {
         _closingUnusableSocketOnCreateStream(logger, subchannelId, address, null);
     }
+
+    public static void ClosingSocketFromIdleTimeoutOnCreateStream(ILogger logger, int subchannelId, BalancerAddress address, TimeSpan idleTimeout)
+    {
+        _closingSocketFromIdleTimeoutOnCreateStream(logger, subchannelId, address, idleTimeout, null);
+    }
 }
 #endif

src/Grpc.Net.Client/GrpcChannel.cs

@@ -61,6 +61,7 @@ public sealed class GrpcChannel : ChannelBase, IDisposable
     internal Uri Address { get; }
     internal HttpMessageInvoker HttpInvoker { get; }
     internal TimeSpan? ConnectTimeout { get; }
+    internal TimeSpan? ConnectionIdleTimeout { get; }
     internal HttpHandlerType HttpHandlerType { get; }
     internal TimeSpan InitialReconnectBackoff { get; }
     internal TimeSpan? MaxReconnectBackoff { get; }
@@ -125,7 +126,7 @@ internal GrpcChannel(Uri address, GrpcChannelOptions channelOptions) : base(addr
 
         var resolverFactory = GetResolverFactory(channelOptions);
         ResolveCredentials(channelOptions, out _isSecure, out _callCredentials);
-        (HttpHandlerType, ConnectTimeout) = CalculateHandlerContext(Logger, address, _isSecure, channelOptions);
+        (HttpHandlerType, ConnectTimeout, ConnectionIdleTimeout) = CalculateHandlerContext(Logger, address, _isSecure, channelOptions);
 
         SubchannelTransportFactory = channelOptions.ResolveService<ISubchannelTransportFactory>(new SubChannelTransportFactory(this));
 
@@ -154,7 +155,7 @@ internal GrpcChannel(Uri address, GrpcChannelOptions channelOptions) : base(addr
             throw new ArgumentException($"Address '{address.OriginalString}' doesn't have a host. Address should include a scheme, host, and optional port. For example, 'https://localhost:5001'.");
         }
         ResolveCredentials(channelOptions, out _isSecure, out _callCredentials);
-        (HttpHandlerType, ConnectTimeout) = CalculateHandlerContext(Logger, address, _isSecure, channelOptions);
+        (HttpHandlerType, ConnectTimeout, ConnectionIdleTimeout) = CalculateHandlerContext(Logger, address, _isSecure, channelOptions);
 #endif
 
         HttpInvoker = channelOptions.HttpClient ?? CreateInternalHttpInvoker(channelOptions.HttpHandler);
@@ -243,12 +244,14 @@ private static HttpHandlerContext CalculateHandlerContext(ILogger logger, Uri ad
         {
             HttpHandlerType type;
             TimeSpan? connectTimeout;
+            TimeSpan? connectionIdleTimeout;
 
 #if NET5_0_OR_GREATER
             var socketsHttpHandler = HttpRequestHelpers.GetHttpHandlerType<SocketsHttpHandler>(channelOptions.HttpHandler)!;
 
             type = HttpHandlerType.SocketsHttpHandler;
             connectTimeout = socketsHttpHandler.ConnectTimeout;
+            connectionIdleTimeout = socketsHttpHandler.PooledConnectionIdleTimeout;
 
             // Check if the SocketsHttpHandler is being shared by channels.
             // It has already been setup by another channel (i.e. ConnectCallback is set) then
@@ -261,6 +264,7 @@ private static HttpHandlerContext CalculateHandlerContext(ILogger logger, Uri ad
                 {
                     type = HttpHandlerType.Custom;
                     connectTimeout = null;
+                    connectionIdleTimeout = null;
                 }
             }
 
@@ -282,8 +286,9 @@ private static HttpHandlerContext CalculateHandlerContext(ILogger logger, Uri ad
 #else
             type = HttpHandlerType.SocketsHttpHandler;
             connectTimeout = null;
+            connectionIdleTimeout = null;
 #endif
-            return new HttpHandlerContext(type, connectTimeout);
+            return new HttpHandlerContext(type, connectTimeout, connectionIdleTimeout);
         }
         if (HttpRequestHelpers.GetHttpHandlerType<HttpClientHandler>(channelOptions.HttpHandler) != null)
         {
@@ -837,6 +842,7 @@ public ISubchannelTransport Create(Subchannel subchannel)
                     subchannel,
                     SocketConnectivitySubchannelTransport.SocketPingInterval,
                     _channel.ConnectTimeout,
+                    _channel.ConnectionIdleTimeout ?? TimeSpan.FromMinutes(1),
                     _channel.LoggerFactory,
                     socketConnect: null);
             }
@@ -895,7 +901,7 @@ public static void AddressPathUnused(ILogger logger, string address)
         }
     }
 
-    private readonly record struct HttpHandlerContext(HttpHandlerType HttpHandlerType, TimeSpan? ConnectTimeout = null);
+    private readonly record struct HttpHandlerContext(HttpHandlerType HttpHandlerType, TimeSpan? ConnectTimeout = null, TimeSpan? ConnectionIdleTimeout = null);
 }
 
 internal enum HttpHandlerType

test/FunctionalTests/Balancer/BalancerHelpers.cs

@@ -135,13 +135,14 @@ public static Task<GrpcChannel> CreateChannel(
         bool? connect = null,
         RetryPolicy? retryPolicy = null,
         Func<Socket, DnsEndPoint, CancellationToken, ValueTask>? socketConnect = null,
-        TimeSpan? connectTimeout = null)
+        TimeSpan? connectTimeout = null,
+        TimeSpan? connectionIdleTimeout = null)
     {
         var resolver = new TestResolver();
         var e = endpoints.Select(i => new BalancerAddress(i.Host, i.Port)).ToList();
         resolver.UpdateAddresses(e);
 
-        return CreateChannel(loggerFactory, loadBalancingConfig, resolver, httpMessageHandler, connect, retryPolicy, socketConnect, connectTimeout);
+        return CreateChannel(loggerFactory, loadBalancingConfig, resolver, httpMessageHandler, connect, retryPolicy, socketConnect, connectTimeout, connectionIdleTimeout);
     }
 
     public static async Task<GrpcChannel> CreateChannel(
@@ -152,12 +153,13 @@ public static async Task<GrpcChannel> CreateChannel(
         bool? connect = null,
         RetryPolicy? retryPolicy = null,
         Func<Socket, DnsEndPoint, CancellationToken, ValueTask>? socketConnect = null,
-        TimeSpan? connectTimeout = null)
+        TimeSpan? connectTimeout = null,
+        TimeSpan? connectionIdleTimeout = null)
     {
         var services = new ServiceCollection();
         services.AddSingleton<ResolverFactory>(new TestResolverFactory(resolver));
         services.AddSingleton<IRandomGenerator>(new TestRandomGenerator());
-        services.AddSingleton<ISubchannelTransportFactory>(new TestSubchannelTransportFactory(TimeSpan.FromSeconds(0.5), connectTimeout, socketConnect));
+        services.AddSingleton<ISubchannelTransportFactory>(new TestSubchannelTransportFactory(TimeSpan.FromSeconds(0.5), connectTimeout, connectionIdleTimeout ?? TimeSpan.FromMinutes(1), socketConnect));
         services.AddSingleton<LoadBalancerFactory>(new LeastUsedBalancerFactory());
 
         var serviceConfig = new ServiceConfig();
@@ -214,12 +216,14 @@ internal class TestSubchannelTransportFactory : ISubchannelTransportFactory
     {
         private readonly TimeSpan _socketPingInterval;
         private readonly TimeSpan? _connectTimeout;
+        private readonly TimeSpan _connectionIdleTimeout;
         private readonly Func<Socket, DnsEndPoint, CancellationToken, ValueTask>? _socketConnect;
 
-        public TestSubchannelTransportFactory(TimeSpan socketPingInterval, TimeSpan? connectTimeout, Func<Socket, DnsEndPoint, CancellationToken, ValueTask>? socketConnect)
+        public TestSubchannelTransportFactory(TimeSpan socketPingInterval, TimeSpan? connectTimeout, TimeSpan connectionIdleTimeout, Func<Socket, DnsEndPoint, CancellationToken, ValueTask>? socketConnect)
         {
             _socketPingInterval = socketPingInterval;
             _connectTimeout = connectTimeout;
+            _connectionIdleTimeout = connectionIdleTimeout;
             _socketConnect = socketConnect;
         }
 
@@ -230,6 +234,7 @@ public ISubchannelTransport Create(Subchannel subchannel)
                 subchannel,
                 _socketPingInterval,
                 _connectTimeout,
+                _connectionIdleTimeout,
                 subchannel._manager.LoggerFactory,
                 _socketConnect);
 #else

test/FunctionalTests/Balancer/ConnectionTests.cs

@@ -141,6 +141,45 @@ async Task<HelloReply> UnaryMethod(HelloRequest request, ServerCallContext conte
         await ExceptionAssert.ThrowsAsync<OperationCanceledException>(() => connectTask).DefaultTimeout();
     }
 
+    [Test]
+    public async Task Active_UnaryCall_ConnectionIdleTimeout_SocketRecreated()
+    {
+        // Ignore errors
+        SetExpectedErrorsFilter(writeContext =>
+        {
+            return true;
+        });
+
+        Task<HelloReply> UnaryMethod(HelloRequest request, ServerCallContext context)
+        {
+            return Task.FromResult(new HelloReply { Message = request.Name });
+        }
+
+        // Arrange
+        using var endpoint = BalancerHelpers.CreateGrpcEndpoint<HelloRequest, HelloReply>(50051, UnaryMethod, nameof(UnaryMethod));
+
+        var connectionIdleTimeout = TimeSpan.FromSeconds(1);
+        var channel = await BalancerHelpers.CreateChannel(
+            LoggerFactory,
+            new PickFirstConfig(),
+            new[] { endpoint.Address },
+            connectionIdleTimeout: connectionIdleTimeout).DefaultTimeout();
+
+        Logger.LogInformation("Connecting channel.");
+        await channel.ConnectAsync();
+
+        await Task.Delay(connectionIdleTimeout);
+
+        var client = TestClientFactory.Create(channel, endpoint.Method);
+        var response = await client.UnaryCall(new HelloRequest { Name = "Test!" }).ResponseAsync.DefaultTimeout();
+
+        // Assert
+        Assert.AreEqual("Test!", response.Message);
+
+        AssertHasLog(LogLevel.Debug, "ClosingSocketFromIdleTimeoutOnCreateStream", "Subchannel id '1' socket 127.0.0.1:50051 is being closed because it exceeds the idle timeout of 00:00:01.");
+        AssertHasLog(LogLevel.Trace, "ConnectingOnCreateStream", "Subchannel id '1' doesn't have a connected socket available. Connecting new stream socket for 127.0.0.1:50051.");
+    }
+
     [Test]
     public async Task Active_UnaryCall_MultipleStreams_UnavailableAddress_FallbackToWorkingAddress()
     {

test/Grpc.Net.Client.Tests/Balancer/StreamWrapperTests.cs

@@ -25,6 +25,54 @@ namespace Grpc.Net.Client.Tests.Balancer;
 [TestFixture]
 public class StreamWrapperTests
 {
+    [Test]
+    public async Task ReadAsync_ExactSize_Read()
+    {
+        // Arrange
+        var ms = new MemoryStream(new byte[] { 4 });
+        var data = new List<ReadOnlyMemory<byte>>
+        {
+            new byte[] { 1, 2, 3 }
+        };
+        var streamWrapper = new StreamWrapper(ms, s => { }, data);
+        var buffer = new byte[3];
+
+        // Act & Assert
+        Assert.AreEqual(3, await streamWrapper.ReadAsync(buffer));
+        Assert.AreEqual(1, buffer[0]);
+        Assert.AreEqual(2, buffer[1]);
+        Assert.AreEqual(3, buffer[2]);
+
+        Assert.AreEqual(1, await streamWrapper.ReadAsync(buffer));
+        Assert.AreEqual(4, buffer[0]);
+
+        Assert.AreEqual(0, await streamWrapper.ReadAsync(buffer));
+    }
+
+    [Test]
+    public async Task ReadAsync_BiggerThanNeeded_Read()
+    {
+        // Arrange
+        var ms = new MemoryStream(new byte[] { 4 });
+        var data = new List<ReadOnlyMemory<byte>>
+        {
+            new byte[] { 1, 2, 3 }
+        };
+        var streamWrapper = new StreamWrapper(ms, s => { }, data);
+        var buffer = new byte[4];
+
+        // Act & Assert
+        Assert.AreEqual(3, await streamWrapper.ReadAsync(buffer));
+        Assert.AreEqual(1, buffer[0]);
+        Assert.AreEqual(2, buffer[1]);
+        Assert.AreEqual(3, buffer[2]);
+
+        Assert.AreEqual(1, await streamWrapper.ReadAsync(buffer));
+        Assert.AreEqual(4, buffer[0]);
+
+        Assert.AreEqual(0, await streamWrapper.ReadAsync(buffer));
+    }
+
     [Test]
     public async Task ReadAsync_MultipleInitialData_ReadInOrder()
     {

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

@@ -208,6 +208,34 @@ public void Build_InsecureCredentialsWithHttps_ThrowsError()
         Assert.AreEqual("Channel is configured with insecure channel credentials and can't use a HttpClient with a 'https' scheme.", ex.Message);
     }
 
+#if SUPPORT_LOAD_BALANCING
+    [Test]
+    public void Build_ConnectTimeout_ReadFromSocketsHttpHandler()
+    {
+        // Arrange & Act
+        var channel = GrpcChannel.ForAddress("https://localhost", CreateGrpcChannelOptions(o => o.HttpHandler = new SocketsHttpHandler
+        {
+            ConnectTimeout = TimeSpan.FromSeconds(1)
+        }));
+
+        // Assert
+        Assert.AreEqual(TimeSpan.FromSeconds(1), channel.ConnectTimeout);
+    }
+
+    [Test]
+    public void Build_ConnectionIdleTimeout_ReadFromSocketsHttpHandler()
+    {
+        // Arrange & Act
+        var channel = GrpcChannel.ForAddress("https://localhost", CreateGrpcChannelOptions(o => o.HttpHandler = new SocketsHttpHandler
+        {
+            PooledConnectionIdleTimeout = TimeSpan.FromSeconds(1)
+        }));
+
+        // Assert
+        Assert.AreEqual(TimeSpan.FromSeconds(1), channel.ConnectionIdleTimeout);
+    }
+#endif
+
     [Test]
     public void Build_HttpClientAndHttpHandler_ThrowsError()
     {