public Task <TResponse> Process <TService, TResponse>(TService service, IContainer container) where TService : IService <TResponse>
{
var handlerType = typeof(IProvideService <,>).MakeGenericType(typeof(TService), typeof(TResponse));
var handlerFunc = (Func <object, TService, IServiceContext, Task <TResponse> >)Processors.GetOrAdd(handlerType, t => ReflectionExtensions.MakeServiceHandler <TService, TResponse>(handlerType));
var handler = container.Resolve(handlerType);
if (handler == null)
{
Logger.ErrorEvent("ProcessFailure", "No handler [{ServiceType:l}] response [{Response:l}]", typeof(TService).FullName, typeof(TResponse).FullName);
return(Task.FromResult(default(TResponse)));
}
// Todo: both units of work should come from the pipeline not the container
var context = new HandleContext(container.Resolve <Aggregates.UnitOfWork.IDomain>(), container.Resolve <Aggregates.UnitOfWork.IApplication>(), container.Resolve <IProcessor>(), container);
return(handlerFunc(handler, service, context));
}
public Task <TResponse> Process <TQuery, TResponse>(TQuery query, IContainer container) where TQuery : IQuery <TResponse>
{
var handlerType = typeof(IHandleQueries <,>).MakeGenericType(typeof(TQuery), typeof(TResponse));
var handlerFunc = (Func <object, TQuery, IHandleContext, Task <TResponse> >)Processors.GetOrAdd(handlerType, t => ReflectionExtensions.MakeQueryHandler <TQuery, TResponse>(handlerType));
var handler = container.Resolve(handlerType);
if (handler == null)
{
Logger.ErrorEvent("ProcessFailure", "No handler [{QueryType:l}] response [{Response:l}]", typeof(TQuery).FullName, typeof(TResponse).FullName);
return(null);
}
// Todo: both units of work should come from the pipeline not the container
var context = new HandleContext(container.Resolve <IDomainUnitOfWork>(), container.Resolve <IUnitOfWork>(), container);
return(handlerFunc(handler, query, context));
}
public void Invoke(IncomingContext context, Action next)
{
ActiveSagaInstance saga;
if (context.TryGet(out saga) && saga.NotFound && saga.SagaType == context.MessageHandler.Instance.GetType())
{
next();
return;
}
var messageHandler = context.Get <AsyncMessageHandler>();
//var handleContext = new HandleContext { Bus = Bus, Context = context };
//messageHandler.Invocation(messageHandler.Handler, context.IncomingLogicalMessage.Instance, handleContext).Wait();
Task.Run((Func <Task>)(async() =>
{
var handleContext = new HandleContext {
Bus = Bus, Context = context
};
await messageHandler.Invocation(messageHandler.Handler, context.IncomingLogicalMessage.Instance, handleContext);
})).Wait();
next();
}
// Todo: all the logging and timing can be moved into a "Debug Dispatcher" which can be registered as the IDispatcher if the user wants
private async Task Process(Object @event, IEventDescriptor descriptor = null, long?position = null)
{
var eventType = _mapper.GetMappedTypeFor(@event.GetType());
Stopwatch s = null;
var handleContext = new HandleContext
{
Bus = _bus,
EventDescriptor = descriptor
};
using (_eventsTimer.NewContext())
{
if (Logger.IsDebugEnabled)
{
Logger.DebugFormat("Processing event {0} at position {1}. Size of queue: {2}/{3}", eventType.FullName, position, _processingQueueSize, _maxQueueSize);
}
using (var childBuilder = _builder.CreateChildBuilder())
{
var handlerGenericType = typeof(IHandleMessagesAsync <>).MakeGenericType(eventType);
List <dynamic> handlers = childBuilder.BuildAll(handlerGenericType).ToList();
if (handlers.Count == 0)
{
return;
}
var success = false;
var retry = 0;
do
{
var uows = new ConcurrentStack <IEventUnitOfWork>();
var mutators = childBuilder.BuildAll <IEventMutator>();
if (Logger.IsDebugEnabled)
{
s = Stopwatch.StartNew();
}
if (mutators != null && mutators.Any())
{
Parallel.ForEach(mutators, _parallelOptions, mutate =>
{
//if (Logger.IsDebugEnabled)
Logger.DebugFormat("Mutating incoming event {0} with mutator {1}", eventType.FullName, mutate.GetType().FullName);
@event = mutate.MutateIncoming(@event, descriptor, position);
});
}
await childBuilder.BuildAll <IEventUnitOfWork>().ForEachAsync(2, async(uow) =>
{
uows.Push(uow);
uow.Builder = childBuilder;
await uow.Begin();
});
if (Logger.IsDebugEnabled)
{
s.Stop();
Logger.DebugFormat("UOW.Begin for event {0} took {1} ms", eventType.FullName, s.ElapsedMilliseconds);
}
try
{
if (Logger.IsDebugEnabled)
{
s.Restart();
}
Func <dynamic, Task> processor = async(handler) =>
{
using (_handlerTimer.NewContext())
{
var handlerRetries = 0;
var handlerSuccess = false;
do
{
try
{
Stopwatch handlerWatch = null;
if (Logger.IsDebugEnabled)
{
Logger.DebugFormat("Executing event {0} on handler {1}", eventType.FullName, handler.GetType().FullName);
handlerWatch = Stopwatch.StartNew();
}
var lambda = _objectInvoker.Invoker(handler, eventType);
await lambda(handler, @event, handleContext);
if (Logger.IsDebugEnabled)
{
handlerWatch.Stop();
Logger.DebugFormat("Executing event {0} on handler {1} took {2} ms", eventType.FullName, handler.GetType().FullName, handlerWatch.ElapsedMilliseconds);
}
handlerSuccess = true;
}
catch (RetryException e)
{
Logger.InfoFormat("Received retry signal while dispatching event {0} to {1}. Retry: {2}/3\nException: {3}", eventType.FullName, handler.FullName, handlerRetries, e);
handlerRetries++;
}
} while (!handlerSuccess && (_maxRetries == -1 || handlerRetries <= _maxRetries));
if (!handlerSuccess)
{
Logger.ErrorFormat("Failed executing event {0} on handler {1}", eventType.FullName, handler.FullName);
throw new RetryException(String.Format("Failed executing event {0} on handler {1}", eventType.FullName, handler.FullName));
}
}
};
// Run each handler in parallel (or not) (if handler ever is ASYNC can't use Parallel)
if (_parallelHandlers)
{
await handlers.ForEachAsync(_parallelOptions.MaxDegreeOfParallelism, processor);
}
else
{
foreach (var handler in handlers)
{
await processor(handler);
}
}
if (Logger.IsDebugEnabled)
{
s.Stop();
Logger.DebugFormat("Processing event {0} took {1} ms", eventType.FullName, s.ElapsedMilliseconds);
}
}
catch (Exception e)
{
var trailingExceptions = new ConcurrentBag <Exception>();
await uows.Generate().ForEachAsync(2, async(uow) =>
{
try
{
await uow.End(e);
}
catch (Exception endException)
{
trailingExceptions.Add(endException);
}
});
if (trailingExceptions.Any())
{
var exceptions = trailingExceptions.ToList();
exceptions.Insert(0, e);
e = new System.AggregateException(exceptions);
}
// Only log if the event has failed more than half max retries indicating a possible non-transient error
if (retry > (_maxRetries / 2))
{
Logger.InfoFormat("Encountered an error while processing {0}. Retry {1}/{2}\nPayload: {3}\nException details:\n{4}", eventType.FullName, retry, _maxRetries, JsonConvert.SerializeObject(@event), e);
}
else
{
Logger.DebugFormat("Encountered an error while processing {0}. Retry {1}/{2}\nPayload: {3}\nException details:\n{4}", eventType.FullName, retry, _maxRetries, JsonConvert.SerializeObject(@event), e);
}
_errorsMeter.Mark();
retry++;
Thread.Sleep(10);
continue;
}
// Failures when executing UOW.End `could` be transient (network or disk hicup)
// A failure of 1 uow in a chain of 5 is a problem as it could create a mangled DB (partial update via one uow then crash)
// So we'll just keep retrying the failing UOW forever until it succeeds.
if (Logger.IsDebugEnabled)
{
s.Restart();
}
var endSuccess = false;
var endRetry = 0;
while (!endSuccess)
{
try
{
await uows.Generate().ForEachAsync(2, async(uow) =>
{
try
{
await uow.End();
}
catch
{
// If it failed it needs to go back on the stack
uows.Push(uow);
throw;
}
});
endSuccess = true;
}
catch (Exception e)
{
if (endRetry > (_maxRetries / 2))
{
Logger.ErrorFormat("UOW.End failure while processing event {0} - retry {1}/{3}\nException:\n{2}", eventType.FullName, retry, e, _maxRetries);
}
else
{
Logger.DebugFormat("UOW.End failure while processing event {0} - retry {1}/{3}\nException:\n{2}", eventType.FullName, retry, e, _maxRetries);
}
endRetry++;
Thread.Sleep(50);
}
}
if (Logger.IsDebugEnabled)
{
s.Stop();
Logger.DebugFormat("UOW.End for event {0} took {1} ms", eventType.FullName, s.ElapsedMilliseconds);
}
success = true;
} while (!success && (_maxRetries == -1 || retry < _maxRetries));
if (!success)
{
var message = String.Format("Encountered an error while processing {0}. Ran out of retries, dropping event.\nPayload: {3}", eventType.FullName, JsonConvert.SerializeObject(@event));
if (_dropEventFatal)
{
Logger.Fatal(message);
throw new SubscriptionCanceled(message);
}
Logger.Error(message);
}
}
}
_eventsMeter.Mark();
}
