private void StartAcceptingConnectionsCore(IConnectionListener listener)
{
// REVIEW: Multiple accept loops in parallel?
_ = AcceptConnectionsAsync();
async Task AcceptConnectionsAsync()
{
try
{
while (true)
{
var connection = await listener.AcceptAsync();
if (connection == null)
{
// We're done listening
break;
}
var id = Interlocked.Increment(ref _lastConnectionId);
var kestrelConnection = new KestrelConnection(id, _serviceContext, _connectionDelegate, connection, _serviceContext.Log);
ThreadPool.UnsafeQueueUserWorkItem(kestrelConnection, preferLocal: false);
}
}
catch (Exception ex)
{
// REVIEW: If the accept loop ends should this trigger a server shutdown? It will manifest as a hang
Log.LogCritical(0, ex, "The connection listener failed to accept any new connections.");
}
finally
{
_acceptLoopTcs.TrySetResult(null);
}
}
}
private void StartAcceptingConnectionsCore(IConnectionListener listener)
{
// REVIEW: Multiple accept loops in parallel?
_ = AcceptConnectionsAsync();
async Task AcceptConnectionsAsync()
{
try
{
while (true)
{
var connection = await listener.AcceptAsync();
if (connection == null)
{
// We're done listening
break;
}
_ = Execute(new KestrelConnection(connection, _serviceContext.Log));
}
}
catch (Exception ex)
{
// REVIEW: If the accept loop ends should this trigger a server shutdown? It will manifest as a hang
Log.LogCritical(0, ex, "The connection listener failed to accept any new connections.");
}
finally
{
_acceptLoopTcs.TrySetResult(null);
}
}
}
async void AcceptIfNecessaryAsync(bool startAccepting)
{
if (IsAcceptNecessary)
{
using (await ThisLock.TakeLockAsync())
{
while (IsAcceptNecessary)
{
Exception unexpectedException = null;
try
{
var acceptTask = listener.AcceptAsync();
// Assigning task to variable to supress warning about not awaiting the task
var continuation = acceptTask.ContinueWith(
handleCompletedAcceptAsync,
CancellationToken.None,
TaskContinuationOptions.RunContinuationsAsynchronously, // don't block our accept processing loop
ActionItem.IOTaskScheduler); // Run the continuation on the IO Thread Scheduler. Protects against thread starvation
pendingAccepts++;
}
catch (CommunicationException exception)
{
DiagnosticUtility.TraceHandledException(exception, TraceEventType.Information);
}
catch (Exception exception)
{
if (Fx.IsFatal(exception))
{
throw;
}
if (startAccepting)
{
// Since we're under a call to StartAccepting(), just throw the exception up the stack.
throw;
}
if ((errorCallback == null) && !ExceptionHandlerHelper.HandleTransportExceptionHelper(exception))
{
throw;
}
unexpectedException = exception;
}
if ((unexpectedException != null) && (errorCallback != null))
{
errorCallback(unexpectedException);
}
}
}
}
}
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
_connectionListener = await _connectionListenerFactory.BindAsync(new IPEndPoint(IPAddress.Loopback, 6000), stoppingToken);
while (true)
{
ConnectionContext connection = await _connectionListener.AcceptAsync(stoppingToken);
// AcceptAsync will return null upon disposing the listener
if (connection == null)
{
break;
}
// In an actual server, ensure all accepted connections are disposed prior to completing
_ = Accept(connection);
}
}
private void StartAcceptingConnectionsCore(IConnectionListener <T> listener)
{
// REVIEW: Multiple accept loops in parallel?
_ = AcceptConnectionsAsync();
async Task AcceptConnectionsAsync()
{
try
{
while (true)
{
var connection = await listener.AcceptAsync();
if (connection == null)
{
// We're done listening
break;
}
// Add the connection to the connection manager before we queue it for execution
var id = _transportConnectionManager.GetNewConnectionId();
var kestrelConnection = new KestrelConnection <T>(
id, _serviceContext, _transportConnectionManager, _connectionDelegate, connection, Log);
_transportConnectionManager.AddConnection(id, kestrelConnection);
Log.ConnectionAccepted(connection.ConnectionId);
KestrelEventSource.Log.ConnectionQueuedStart(connection);
ThreadPool.UnsafeQueueUserWorkItem(kestrelConnection, preferLocal: false);
}
}
catch (Exception ex)
{
// REVIEW: If the accept loop ends should this trigger a server shutdown? It will manifest as a hang
Log.LogCritical(0, ex, "The connection listener failed to accept any new connections.");
}
finally
{
_acceptLoopTcs.TrySetResult();
}
}
}
public static async Task RunEchoServerAsync(IConnectionListener listener, CancellationToken cancellationToken = default)
{
while (true)
{
var connection = await listener.AcceptAsync(cancellationToken);
_ = Task.Run(async() =>
{
try
{
// This is the simplest implementation of an echo server, copy the input to the output
await connection.Transport.Input.CopyToAsync(connection.Transport.Output, cancellationToken);
}
finally
{
await connection.DisposeAsync();
}
});
}
}
public static async Task RunServerAsync(IConnectionListener listener, ConnectionDelegate connectionDelegate, CancellationToken cancellationToken = default)
{
ValueTask unbindTask = default;
cancellationToken.Register(() =>
{
unbindTask = listener.UnbindAsync();
});
while (true)
{
var connection = await listener.AcceptAsync(cancellationToken);
if (connection == null)
{
break;
}
_ = Task.Run(async() =>
{
try
{
await connectionDelegate(connection);
}
finally
{
await connection.DisposeAsync();
}
});
}
await unbindTask;
// TODO: Wait for opened connections to close
await listener.DisposeAsync();
}
public ValueTask <ConnectionContext?> AcceptAsync(CancellationToken cancellationToken = default) => _connectionListener.AcceptAsync(cancellationToken);
public async Task RunListenerAsync(IConnectionListener listener, ConnectionDelegate connectionDelegate, CancellationToken cancellationToken = default)
{
var unbindTask = new TaskCompletionSource <object>();
var connections = new ConcurrentDictionary <string, (ConnectionContext Connection, Task ExecutionTask)>();
cancellationToken.Register(async() =>
{
try
{
await listener.UnbindAsync();
}
finally
{
unbindTask.TrySetResult(null);
}
});
async Task ExecuteConnectionAsync(ConnectionContext connection)
{
await Task.Yield();
try
{
await connectionDelegate(connection);
}
catch (ConnectionAbortedException)
{
// Don't let connection aborted exceptions out
}
catch (Exception ex)
{
_logger.LogError(ex, "Unexpected exception from connection {ConnectionId}", connection.ConnectionId);
}
finally
{
await connection.DisposeAsync();
// Remove the connection from tracking
connections.TryRemove(connection.ConnectionId, out _);
}
}
while (true)
{
try
{
var connection = await listener.AcceptAsync(cancellationToken);
if (connection == null)
{
// Null means we don't have anymore connections
break;
}
connections[connection.ConnectionId] = (connection, ExecuteConnectionAsync(connection));
}
catch (OperationCanceledException)
{
// The accept loop was cancelled
break;
}
}
// Wait for the listener to close, no new connections will be established
await unbindTask.Task;
// TODO: Give connections a chance to close gracefully
var tasks = new List <Task>(connections.Count);
// Abort all connections still in flight
foreach (var pair in connections)
{
pair.Value.Connection.Abort();
tasks.Add(pair.Value.ExecutionTask);
}
await Task.WhenAll(tasks);
await listener.DisposeAsync();
}
public async Task <IConnection> AcceptAsync()
{
return(new BufferedConnection(await connectionListener.AcceptAsync(), flushTimeout, writeBufferSize));
}