public async Task Route(CancellationToken cancellationToken)
{
if (IsRunning)
{
throw new InvalidOperationException($"The [{nameof(DefaultMessageRouter)}] is already running.");
}
else
{
IsRunning = true;
}
await foreach (var handlingProcess in _messageReceiver.Receive(cancellationToken))
{
Stopwatch stopWatch = null;
if (_logger.IsEnabled(LogLevel.Trace))
{
stopWatch = new Stopwatch();
stopWatch.Start();
}
var messageType = handlingProcess.Message.GetType();
var(handlerDelegate, handlerType) = _messageHandlersRegistry.HandlerDelegateFor(messageType);
using var scope = _serviceProvider.CreateScope();
var handler = (IMessageHandler)scope.ServiceProvider.GetService(handlerType);
_logger.LogTrace(
message: LogMessageHandlingTemplate,
Thread.CurrentThread.ManagedThreadId, messageType, handlerType
);
// We do busy-waiting instead of Task.Delay because it's cheaper to await on remove/add-misses because they're quick, rather than yield to another thread.
var handlerTask = Task.Run(async() =>
{
try
{
await handler
.Handle(handlingProcess.Message, handlerDelegate, cancellationToken)
.ConfigureAwait(false);
handlingProcess.ToHandled();
}
catch (Exception exception)
{
handlingProcess.ToError(exception);
}
}).AnywayContinuation(action: task =>
{
// Busy-waiting
RunningTask removedTask;
while (!_runningTasks.TryRemove(task.Id, out removedTask))
{
_spinForRemove.SpinOnce();
}
if (_logger.IsEnabled(LogLevel.Trace))
{
stopWatch.Stop();
_logger.LogTrace(
message: LogMessageRemovedTemplate,
removedTask.Name, removedTask.Task.Id, stopWatch.ElapsedMilliseconds
);
}
}, continueTask: out _, cancellationToken: cancellationToken);
// Busy-waiting
while (!_runningTasks.TryAdd(handlerTask.Id, new RunningTask(messageType.Name, handlerTask)))
{
_spinForAdd.SpinOnce();
}
_logger.LogTrace(
message: LogMessageAddedForHandling, Thread.CurrentThread.ManagedThreadId, messageType.Name, handlerTask.Id
);
}
}
