Jason
Here is my module that works as you are trying to (I believe). Note I am
doing the send in the MessageCompleted handler,not in the messageFailure.
Ignore the lame method of configuration for the NumberOfRetries value...:)
public class ExceptionHandlingMessageModule : IMessageModule,
IBusConfigurationAware
{
public static int? NumberOfRetries;
private readonly Hashtable<string, ErrorCounter> failureCounts = new
Hashtable<string, ErrorCounter>();
private ITransport transport;
public void Configure(AbstractRhinoServiceBusFacility facility,
IConfiguration configuration)
{
if (!NumberOfRetries.HasValue)
NumberOfRetries = facility.NumberOfRetries;
}
public void Init(ITransport transport)
{
this.transport = transport;
transport.MessageProcessingFailure +=
TransportOnMessageProcessingFailure;
transport.MessageProcessingCompleted +=
TransportOnMessageProcessingCompleted;
}
public void Stop(ITransport transport)
{
transport.MessageProcessingFailure -=
TransportOnMessageProcessingFailure;
transport.MessageProcessingCompleted -=
TransportOnMessageProcessingCompleted;
}
private void
TransportOnMessageProcessingCompleted(CurrentMessageInformation information,
Exception e)
{
ErrorCounter val = null;
failureCounts.Read(reader =>
reader.TryGetValue(information.TransportMessageId, out val));
if (val == null)
return;
if (val.FailureCount == NumberOfRetries)
{
var messageType = (information.Message ?? "no
message").ToString();
// Log.For(this).Info("Sending error message for exception
'{0}'",e);
transport.Send(new Endpoint {Uri = information.Source},
new[]
{
new ExceptionMessage
{
ErrorText = val.Exception.Message,
ExceptionToString = val.Exception.ToString(),
Timestamp = DateTime.Now,
MessageType = messageType,
MessageId = information.MessageId,
Source = information.Source,
Message = information.Message
}
});
}
if (e == null)
{
failureCounts.Write(writer =>
writer.Remove(information.TransportMessageId));
}
}
private void
TransportOnMessageProcessingFailure(CurrentMessageInformation information,
Exception exception)
{
failureCounts.Write(writer =>
{
ErrorCounter errorCounter;
if
(writer.TryGetValue(information.TransportMessageId, out errorCounter) ==
false)
{
errorCounter = new ErrorCounter
{
FailureCount = 0,
Exception
= exception
};
writer.Add(information.TransportMessageId, errorCounter);
}
errorCounter.FailureCount += 1;
});
}
private class ErrorCounter
{
public Exception Exception;
public int FailureCount;
}
}
On Fri, Oct 2, 2009 at 7:20 AM, Jason Meckley <[email protected]>wrote:
>
> I use RQ for all my projects, but I'm not seeing any exceptions. in
> the code i provided originally I'm replying on the transport within
> the MessageProcessingFailure event after the maximum number of
> failures occurs. should I move this to MessageProcessingCompleted,
> checking the number of failed attempts to determine if a reply should
> be sent?
>
> On Oct 2, 10:09 am, Ayende Rahien <[email protected]> wrote:
> > And if this after the rollback, it also explains it.
> > Depending on what kind of queue you use. If you are using MSMQ, it will
> be
> > silently ignored. If you are using RQ, it will throw.
> >
> > On Fri, Oct 2, 2009 at 4:04 PM, Jason Meckley <[email protected]
> >wrote:
> >
> >
> >
> > > I originally got the idea from the LoadBalancerMessageModule. I will
> > > log some stats on Transaction.Current to see what's happening there.
> >
> > > if this is before rollback, then that would explain why the message is
> > > not sent, correct?
> >
> > > On Oct 2, 9:17 am, Ayende Rahien <[email protected]> wrote:
> > > > Jason,
> > > > I don't think that you can send messages from message modules.
> > > > The idea never occurred to me, to tell you the truth.
> > > > In this particular case, I can't recall off hand what the transaction
> > > state
> > > > if for this case, but I think it is just before we roll it back, or
> maybe
> > > > even without a transaction.
> > > > Both of those scenarios will explain why you aren't seeing the
> message
> > > being
> > > > sent.
> >
> > > > On Thu, Oct 1, 2009 at 8:37 PM, Jason Meckley <
> [email protected]
> > > >wrote:
> >
> > > > > I have ~2 dozen consumers that all handle the happy days scenario
> (no
> > > > > exceptions). I then have a message module which will handle the
> > > > > exceptions. the code my be easier to understand
> >
> > > > > public class OutOfRetriesMessageModule : IMessageModule
> > > > > {
> > > > > private readonly IReflection reflection;
> > > > > private readonly int numberOfRetries;
> > > > > private readonly Hashtable<Guid, int> failures;
> >
> > > > > private ITransport theTransport;
> >
> > > > > public OutOfRetriesMessageModule(int numberOfRetries,
> > > > > Hashtable<Guid, int> failures, IReflection reflection)
> > > > > {
> > > > > this.numberOfRetries = numberOfRetries;
> > > > > this.failures = failures;
> > > > > this.reflection = reflection;
> > > > > }
> >
> > > > > public void Init(ITransport transport)
> > > > > {
> > > > > theTransport = transport;
> > > > > transport.MessageProcessingFailure +=
> > > > > message_processing_failure_send_failure_notice_if_necessary;
> > > > > transport.MessageProcessingCompleted +=
> > > > > message_processing_completed_clear_failures_if_necessary;
> > > > > }
> >
> > > > > public void Stop(ITransport transport)
> > > > > {
> > > > > transport.MessageProcessingFailure -=
> > > > > message_processing_failure_send_failure_notice_if_necessary;
> > > > > transport.MessageProcessingCompleted -=
> > > > > message_processing_completed_clear_failures_if_necessary;
> > > > > }
> >
> > > > > private void
> > > > > message_processing_failure_send_failure_notice_if_necessary
> > > > > (CurrentMessageInformation information, Exception exception)
> > > > > {
> > > > > var messageId = information.MessageId;
> > > > > if (exception == null) return;
> > > > > if(!typeof
> > > > > (RequestToGenerateReportMessage).IsAssignableFrom
> > > > > (information.Message.GetType())) return;
> >
> > > > > increment_failed_attempts(messageId);
> > > > > if (!has_exceeded_number_of_retries(messageId)) return;
> >
> > > > > send_failure_notice(information);
> > > > > }
> >
> > > > > private void
> > > > > message_processing_completed_clear_failures_if_necessary
> > > > > (CurrentMessageInformation information, Exception exception)
> > > > > {
> > > > > if (exception != null) return;
> > > > > failures.Write(writer => writer.Remove
> > > > > (information.MessageId));
> > > > > }
> >
> > > > > private void increment_failed_attempts(Guid messageId)
> > > > > {
> > > > > failures.Write(writer =>
> > > > > {
> > > > > int attempts;
> > > > > writer.TryGetValue(messageId, out
> > > > > attempts);
> > > > > writer.Add(messageId,
> ++attempts);
> > > > > });
> > > > > }
> >
> > > > > private bool has_exceeded_number_of_retries(Guid id)
> > > > > {
> > > > > var attempts = 0;
> > > > > failures.Read(reader => reader.TryGetValue(id, out
> > > > > attempts));
> > > > > return attempts >= numberOfRetries;
> > > > > }
> >
> > > > > private void send_failure_notice(CurrentMessageInformation
> > > > > information)
> > > > > {
> > > > > var message = information.Message;
> > > > > var generatedReportFailed = new ReportGeneratedMessage
> > > > > {
> > > > > instance_id =
> > > > > reflection.parse_instance_id(message),
> > > > > date = reflection.parse_date
> > > > > (message),
> > > > > region_id =
> > > > > reflection.parse_region_id(message),
> > > > > report_id =
> > > > > reflection.parse_report_id(message),
> > > > > file_name = "",
> > > > > success = false
> > > > > };
> > > > > theTransport.Reply(generatedReportFailed);
> > > > > }
> > > > > }
> >
> > > > > the problem is the system is not throwing an excpetion and I'm not
> > > > > consuming the generatedReportFailed message on the other end. if I
> > > > > move the send_failure_notice logic into the Consume() member of
> each
> > > > > consumer wrapped in a try/catch the workflow is processed correctly
> > > > > and I receive a failure notice on the other end.
> >
> > > > > it what i'm trying to do possible? send/reply a message from within
> > > > > the message module? it would seem I don't need to wrap this in a
> > > > > transactionscope because theTransport will handle that for me. the
> > > > > Transport implementation is RQ.
> >
> > > > > I also tried
> > > > > theTransport.Send(new EndPoint{Url=information.Source}, new
> object[]
> > > > > {generatedReportFailed});
> > > > > but that was throwing timeout exceptions. (duration cannot be
> > > > > negative). or just not working at all.
> >
>
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