I have a WCF service that talks to MSMQ. When I run the service in VS2010’s service test client interface it can place the messages in the proper queues and everything is fine. When I host the WCF service in IIS7 and call the service from my web application all the messages go into the Transactional dead-letter queue.
I setup the application pool and site (the site hosting the WCF service) with identities that I know have specific access to the queues.
Is there something else I can check or that I am doing wrong?
Update:
Well, I think there is something else going on. I created a SUPER simple service that can read and write from the queues without fail. I jsut need to dig deeper and find out. Thanks to everyone who has looks, but I will keep this open so I can report back or if someone may have other ideas. I know it is hard to determine without viewing any code, but it is difficult to post becuase i have a lot to break apart.
Turns out the guys who coded the queue did not setup the queues correctly.
set the ExactlyOnce = false either in code or in your client app.config file.
like this
NetMsmqBinding binding = new NetMsmqBinding(NetMsmqSecurityMode.None);
binding.ExactlyOnce = false;
Hope this will solve the problem.
Cheers
Naushad
Related
We have been tumbling, for more than a month now, with an issue where a wcf msmq service hosted in IIS7.5 (WAS) will stop processing messages from the queue.
We have been unable to narrow it down more than "at some point" it will stop processing messages from the queue. Calling the svc through a http browser call will start the processing again.
After reading really many articles, blogs and forum posts about this issue we have ensured the following: Security settings, protocol bindings and msmq/service naming, but alas: the service will still stop processing messages (at some point).
Encouraged by this article http://www.daczkowski.net/2010/11/19/leveraging-msmq-in-asp-net-application-through-wcf-service/ we seem to have now finally (almost) eliminated the problem for windows server 2008 r2 sp1 64 bit, but it still seems to appear on Windows 7 32 bit.
Now to get to my question: Can anyone tell me if there actually exists a guarentee (documentation on this would be appreciated) that a msmq WAS hosted wcf service will actually restart (under all conditions) on a IIS7.5 NOT running the AppFabric extension?
I am aware that this question is very compounded, but I'm hard pressed for documentation on why we should extend our OTS package with AppFabric to resolve this restart problem.
Best regards,
Are you're net.msmq endpoints actually using addresses that IIS can bind to a queue name? It's possible to use non-IIS compatible names in the config and WAS won't really ever be able to wake your application up because WAS will only ever register to queues following a path name it can resolve. In that case you need something like AppFabric or a "startup" script to actually activate your services so that they will bind to the queues in their own.
I am writing an application that has one Windows Service that needs to communicate with another Windows Service. The "target" service will accept a request from the "source" service and will perform a task. The "source" service will not wait for a response, so the request should return as soon as possible.
The plan was to have the "target" service host a WCF service which the "source" will communicate with. Once the request is received I need to communicate with the host Windows Service to tell it to do the work. I was thinking that the "target" WCF service would put a message on a MSMQ which the "target" Windows service will monitor. Once this is done the WCF service can return back to the caller.
Does this sound like a sensible approach for allowing a WCF service to tell a hosting Windows Service to perform a task?
Kind Regards
Michael
Allow me to disagree. Based simply on what you've described, using MSMQ to communicate between the "target" WCF service and the hosting Windows service seems extremely heavyweight to me. MSMQ allows different processes to communicate in a failsafe manner. In your case, the WCF service is hosted in the same process as the Windows service. Thus, while MSMQ as a commmunication mechanism between the two would work, it's not necessary.
Additionally, using the MSMQ binding between the "target" WCF service and the "source" WCF service makes sense if the two WCF services are not always running at the same time. For example, if the "target" WCF service is not always running, the MSMQ binding would allow the "source" WCF service to still send tasks. These tasks would be stored in the MSMQ to be retrieved when the "target" WCF service begins running. However, it sounds like both services will be running, so I can't see the need for the MSMQ binding.
For selecting WCF bindings, refer to this SO post.
C# - WCF - inter-process communication
Let me address one other thing. When your "target" WCF service receives a task request from the "source," simply communicating the task back to the Windows service is not going to do anything in and of itself. The Windows service is running, yes, but it does not have a thread of execution that you can leverage. The point is that in order to make task processing asynchronous, you'll need to start a thread to manage the task(s). I would suggest leveraging the ThreadPool to do this.
Hope this helps.
Yeah, that is a good approach. MSMQ is perfect for this task - the source service can send a request to the target by putting a message on the queue via WCF. MSMQ is good anytime you want to send a request to a service for asynchronous processing, especially if you don't need to get a response back. If you do need a response, you can setup the source as a WCF service as well, and the target can send a message back if needed. There are several different ways to accomplish this with the MSMQ binding.
#Matt
Thanks for your help.
After thinking about it a bit more and see how your approach would make things easier to setup and use. I need to have the "target" service send the outcome of the work back to the "source", so I will probably use nettcp and use a callback. The plan then is to setup a new thread, do the work and once its finished send a response back to the "source".
#Andy
Thanks for you help.
I took a look at msmq, but seeing as I would probably have to setup a new thread once I receive the message I might as well let the web service do the work.
I have WCF service hosted in console app. Service tries to connect to opened windows application via DDE protocol. No luck. Where is the problem? Console app is running in my account, as the dde windows app.
I'm not expert in this field, but I believe DDE requires that you have a running message pump (which a console application lacks), so you may have better luck hosting your WCF service in a WinForms app.
You have provided so little details about the problem that is going to be nearly impossible to give you a definitive answer. However, your comment to Allon's answer is interesting.
If i run listener in console without
WCF, all is fine
So your DDE application is listening for something? I now have to assume that you have attempted to create a DDE client that subscribes to an advisory loop via DdeClient.StartAdvise. This method of data retrieval is highly dependent on a message pumping mechanism.
When you create an instance of DdeClient it will by default create its own message pump on a separate thread to receive these advisory notifications. That would explain why it works when you leave your code in a basic console application.
However, when you mix WCF there may be some adding complexities particularly concerning threads that may have to be dealt with manually. The only way I am going to be able to tell is if you provide more information.
I have develop a silverlight chat application. my question is (a) can netmsmqbinding support unlimited connections of wcf service. because first im use pollingduplex binding but it support only 10 connection on iis6 also on server edition.im allready set service throttling options but not effect on server iis. so that now i want to go for netmsmqbinding. please explain me msmqbinding limitations.can its better for chat application or not?
help me for take decision.
Thanks
As far as I know (but I don't know Silverlight all that well), it supports only the basicHttpBinding.
And even if Silverlight did support MSMQ - this is definitely not a good protocol to use when you're creating a chat application. The queue can buffer messages and deliver them later. That works well in many scenarios, but when I chat with someone, I want my message to show up right away - not "some time later".....
So if you really need to use MSMQ in some way, I think you'd have to have a BasicHttp-based front-end service that goes from your Silverlight client to the server, and then on the server actually route your message forward to a MSMQ queue.
Marc
I'm trying to cache some application data that only needs to be instantiated when the application starts. I've tried using HttpRuntime.Cache, creating a static object that is instantiated only when the service starts, and I've tried making the service singleton and using global variables. Every time a new request hits the service I loose state... I could create the WCF service as a windows service I suppose, but I'd love to figure out what's happening here... I see that only one IIS worker process is spawning, but I'm guessing it's unloading and re-loading the service every time.
Am I missing some WCF configuration or possibly not setting it up right in IIS? It's running as a normal 2.0 website within IIS.
This my first post here, if someone can tell me how to post my app.config XML I will... I think stackoverflow is trying to parse it as HTML, it doesn't show up.
Thank you!
Tim
We use enterprise library caching with WCF services, works for us:
http://msdn.microsoft.com/en-us/library/dd203099.aspx
Edit
This answer is a bit old we have now stopped using Enterprise Library Caching, we use app fabric instead, see: http://msdn.microsoft.com/en-us/windowsserver/ee695849