asked on

Timeout receiving asyncronous message using msmq

Hi

I'm trying to learn more about messaging and services using an example by Peter Bromberg from Egghead Cafe (http://www.eggheadcafe.com/articles/20041204.asp - code can be downloaded from http://www.eggheadcafe.com/articles/20041204.zip). The example runs on a single machine but I've been trying to get it to run with the client and server on seperate machines for about 3 days without luck. I added event log messages at different points and it seems to fall over at the async receive on the server (Invoker.cs in the MSMQInvokerService project):

try
                  {
//breaks at this point
Message msg=mq.EndReceive(ar);
//and goes to the catch
                        ICommand cReceived = (ICommand)msg.Body;
                        ServiceBroker.Logger.WriteToLog("ICommand Object Casted.",
                                                System.Diagnostics.EventLogEntryType.Information);
                        cReceived.Execute();
                        ServiceBroker.Logger.WriteToLog("Executed Command at "+DateTime.Now.ToLongTimeString(),
                                                System.Diagnostics.EventLogEntryType.Information);
                  }
                  catch
                  {
                        ServiceBroker.Logger.WriteToLog("Timeout!",
                                                System.Diagnostics.EventLogEntryType.Information);
                  }

If the service is invoked on the server this means that the message has gotten there, right? What am I doing wrong?

Matt

dstanley9

One thing you may try is to post the exception to the event log to see if it actually was a timeout:

catch(Exception exception)
{
ServiceBroker.Logger.WriteToLog("An Exception Occured:\n" + exception.ToString(),
System.Diagnostics.EventLogEntryType.Information);
}

matt_d_p

ASKER

Thanks for the suggestion. Seems it is a timeout out but why? Why the difference between local and remotes? I'm on a home network with 2 pc's linked by a crossover cable. Shouldn't be any load at all.

This is the error in the remote log:

Event Type:      Information
Event Source:      ServiceBroker
Event Category:      None
Event ID:      0
Date:            2006/06/07
Time:            09:45:44 PM
User:            N/A
Computer:      BIGBLACK
Description:
An Exception Occured:
System.Messaging.MessageQueueException: Timeout for the requested operation has expired.
at System.Messaging.MessageQueue.AsynchronousRequest.End()
at System.Messaging.MessageQueue.EndAsyncOperation(IAsyncResult asyncResult)
at System.Messaging.MessageQueue.EndReceive(IAsyncResult asyncResult)
at MSMQInvokerService.Invoker.OnMessageArrival(IAsyncResult ar)

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

While playing I've also introduced a bug in the client now:

FormatName:DIRECT=OS:bigblack\private$\commandtest //writeline of destinationQueue value
System.Messaging.MessageQueueException: The specified format name does not suppo
rt the requested operation. For example, a direct queue format name cannot be de
leted.
at System.Messaging.MessageQueue.SaveQueueProperties()
at System.Messaging.MessageQueue.set_UseJournalQueue(Boolean value)
at ClientSample.QueuedClient.QueueInvokerCommand(ICommand c, String destinati
onQueue) in C:\projects\PosMinder\ClientSample\QueuedClient.cs:line 65

Could this contribute? It complains about the name format yet still seems to get to the server as I see the errors there. Very confusing?

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dstanley9

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matt_d_p

ASKER

If I understand this correctly, there isn't a problem at the server, the server just writes this message each time it "times out" while checking for a message? That explains why I couldn't find anything wrong :). Let me go and find my real problem. Thanks for the help.

dstanley9

Yes, the ReceivedCompleted event will fire in the event of a timeout, but calling EndReceive if there is no message will cause the exception.

You can check the IsCompleted property of the AsyncResult object to see if a message was actually received.