I am having trouble getting the feature recovery on failure to work for my Windows Service Application. I set in up to restart the application on first failure. Then to test in I use this line of code
System.Environment.Exit(-1)
This causes the application to end okay but it doesn't restart.
It is reasonable to suppose that a service process exiting without setting the service status to stopped would constitute a failure. However, that isn't the case. (Perhaps for backwards compatibility; there might be too many third-party services that such a change would break.)
However, if the process exits as the result of an unhandled exception, that is considered a service failure and triggers the recovery options. So if you want to cause the service to fail, raise an exception (and don't catch it).
Related
I want my service to be able to be restarted remotely (by a TCP client which is not part of this question). I configured the service to restart on failure on the Recovery tab for my service. In my code I set the ServiceBase.ExitCode to a non-zero number, say 1. I did not use Environment.Exit to stop the service because it isn't necessary to terminate the process. When I test my service it stops correctly and the Windows System Log reports that my service has stopped with an error. It also names the error. But my service does not restart! When I instead use Environment.Exit(1) the Windows System Log reports that my service has stopped unexpectedly without naming the error. It then does restart the service as if it has failed (like it should).
My question is, why doesn't the service restart with just a non-zero exitcode? The service stops with an error but that isn't failing? Is Environment.Exit the only way to properly trigger a service restart on failure? I liked using the ExitCode better because the System Log is cleaner and more accurate that way.
Did you check the "Enable actions for stops with errors" checkbox on the Recovery tab?
From the technical documentation, the service's exit code is only consulted if that option is checked.
In our production environment, we have a WCF serivce that is very frequently called.
We noticed that sometimes, calls to this service (only this one) fail on timeout for a period of time, after everything falls into place and the service responds correctly again.
I used Dynatrace to try to understand what's happening, I noticed that for the calls resulting on a timeout, the method of the service is never called ! And at the same time the server throw this error
A blocking operation was interrupted by a call to
WSACancelBlockingCall
and the client throws a Timeout Exception.
I want to understand the cause of this errors. Is the server error caused by the client's TimeoutException (when the client close its connection) ? Otherwise why do the server throw this error ?
Can you attach a screenshot of that PurePath?
The TimeoutException is simply thrown by the caller of a service when the called web services doesnt return within the default timeout - typically something like 60s. And - once the client aborts its network connection it will cause the exception in the server who has accepted that connection.
There can be multiple reasons for this slow behavior, e.g: you are maxing out the number of connections you have in your client - or the server implementation is overloaded and cant handle incoming requests. Definitely look at the number of worker threads/connections configured on both sides
If you want specific help on dynatrace freel free to send over the PurePaths - check out http://bit.ly/sharepurepath
hope this helps
For a few weeks now I've been having a really weird problem. I have a couple of services which work just fine when self-hosted in a command line app. However in IIS+AppFabric I cannot access one of the services - I get TimeoutException and am pretty sure that the call doesn't even make it to the service (all services have an aspect to log all calls before doing anything). Note that both services are configured identically with regards to bindings and behaviors by code. I tried many things like putting them on different app pools, disabling some of the transports... And what is really strange that if both services are in one app pool - one of the services works but if I put them on separate threads - the other service times-out. It really drives me nuts...
Also I see pretty often events in the system event log: "A process serving application pool 'Authorization Management' suffered a fatal communication error with the Windows Process Activation Service. The process id was '11852'. The data field contains the error number." The error number is 0x80070218. After the event the service host initializes without problems (I can see my own info log messages) however the service is unreachable.
Does this ring a bell to anyone?
Thanks!
It turned out that I had a bug in the initialization of the services' hosts. I was trying something, and when I removed the try code, apparently I didn't delete the first line which was locking some resource.
Anyway, it is a good lesson. Nevertheless, if your services do not work, your initialization might be buggy...
Sorry about the noice.
My application has 50 service endpoints (such as /mysite/myService.svc). It's hosted in IIS. Intermittently (once every two or three days) a service stops responding. It's never the same service that hangs. While a service is hung, some of the other services work fine and some other are also hung.
All clients (from different computers) get this error:
ServiceModel.CommunicationException
Message: An error occurred while receiving the HTTP response to
https://server/mysite/myservice1.svc.
This could be due to the service endpoint binding not using the HTTP
protocol. This could also be due to an HTTP request context being
aborted by the server (possibly due to the service shutting down).
See server logs for more details.
No exceptions are raised by the server when the client attempts to call the service that is hung. All I have is that error on the client side.
I have to manually recycle the application pool to fix the problem.
Do you know what could be the cause? How can I investigate this issue? I'm willing to take a memory dump of the worker process when a service is hung but I would not know what to search for in the dump.
Update (Aug 13 2009): I have almost ruled out the idea that the server runs out of connections (see comment in Shiraz Bhaiji's answer). I might have a new lead: I log all server-side exceptions in a log file. So in theory, when this occurs on the client, no exceptions are raised on the server; otherwise I'd have proof of that in my logs. But what if an error does occur on the server but is happening at a low level where exceptions are not routed to my exception handling code? I have posted this question about scenarios where low level exceptions cannot be handled. I'll keep you informed of the progress of my investigation.
Sounds like you are running out of connections.
By default WCF has a timeout and therefore holds a connection open for 10 mins.
When you recycle the app pool all connections are closed, and therefore things work again.
To fix it check your code to make sure that you close connections / dispose of proxies.
To resolve this, we set establishSecurityContext to False on the binding.
I have not come across this particular issue but would suggest to turn on tracing/message logging for the WCF service in the config for the service and/or the client app (if you have control over that). I've done this in the last few days for a service that I needed to troubleshoot.
The MSDN link here is a good starting point.
Also see the table in this post for the varying levels of trace detail you can configure. There are several levels which can go from exception only logging to full message details. It is quite quick to set this up in the app.config file.
To parse the log file output use the SvcTraceViewer.exe that comes with the Windows SDK, which if you have it installed should be located in this folder: C:\Program Files\Microsoft SDKs\Windows\v6.0\Bin
Our WCF services occaisionally spawn a worker thread to handle something that the client doesn't care about. The worker threads do not report any status back to the client. In fact, the service has probably already returned results to the client by the time the thread finishes.
One of these background threads recently caused an exception. The exception went unhandled, so IIS crashed.
I can fix this particular exception, but in the future, someone may add some code that causes another unexpected exception. I want to prevent this from crashing IIS in the future.
I know System.Windows.Forms apps can handle thread exceptions by implementing Application.ThreadException. Is there something similar I can do from a WCF service? Or if Application.ThreadException is the way to go, how would I hook it up from a WCF service?
The MSDN documentation for AppDomain.UnhandledException says it does not prevent crashing. Docs for ServiceModel.AsynchronousThreadExceptionHandler suggest it is only for WCF threads.
At a minimum, I'd like to grab a stack trace from the exception before crashing, but avoid future crashes completely would be ideal.
Again, let me stress this is not an exception I want to return as a WCF fault to a client.
Since you don't know what caused the exception, the only sensible thing to do is crash. You have no idea what state the service is in, and you could make things worse by continuing.
Remember that IIS will restart the service for you, clean, and presumably working.
If you're spawning threads, you should always make sure they have exception guards. The AppDomain handling for unhandled exceptions only provides a way to log and trace the error, but it won't stop the host from crashing.
You could take a look at implementing IErrorHandler with a Dispatch Behavior:
http://msdn.microsoft.com/en-us/library/system.servicemodel.dispatcher.ierrorhandler.aspx