We have a Quarkus application that is deployed as an uber jar which is wrapped by an in-house framework that runs it as a Windows service. The framework mirrors the Windows API closely and expects the application to be able to start, then run and finally stop gracefully when signaled by the OS.
The current solution always returns true for start without doing anything (not ideal, but works); it then calls Quarkus.run(); from the run method, which blocks. When stop is called, it calls Quarkus.asyncExit();. That stops the application.
The problem is that Quarkus seems to stop using System.exit(), which makes Windows think the service crashed. Is there a way to avoid that and make it return instead, passing control back to the run method (that called Quarkus.run())?
I realize this is not a typical use case for Quarkus, but graceful controlled start and stop from a calling program should be generally useful. We have not yet tried preventing exit with a security manager, as that seems a bit up in the air with Java 17; see jdk-8199704.
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Fellow experts!
I have faced the following dilemma: some of our tools (executables) are started as scheduled tasks, some are started as services and others as usual desktop apps with interactive Windows user. We are using the code sharing strategy for source management (this is not debatable for this question).
So the solution I want to find is the following:
Detect UI operation at run-time which leads to hanging service/background task (such as say call to Application.ShowException, ShowMessage, MessageDialog, TForm.Show etc.). And when such an action detected I want to raise the exception instead. Then the operation will fail, we will have stack trace etc. but the process will not hang up! The most problematic hang up is when some event processing is done in transaction and then in some of the code used to process event suddenly (because of error in code, design, whatever) there is UI code executed then the process hangs and the DB parts can be locked!
What I think I need to do is: Use DDetours library to intercept WinAPI calls to a certain routines and raise exception instead (so that the process does not hang, but just fail in some method). Also I know that the creation of forms and windows does not hang the app, but only the tries to show them to the user.
Is there some known method of handling this problem? Or maybe there is some list of WinAPI routine set which hangs in service mode?
Thank you in advance.
I've successfully followed the Daemons and Service Guide - Creating XPC Services tutorial, along with the SandboxedFetch sample code and have a working Client / Service setup that is using the new NSXPCConnection class.
What still isn't entirely clear to me is how to properly self-terminate the service application once it has finished its job. I recognize that in many cases, the service is expected to remain alive, but in the use-case I have in mind, the service will be used to only to do some processing that I'd otherwise not perform in the main application. Once that processing is finished, there's no reason for the service application to remain. If the client needs another service at a later date, it can just re-create a new one.
Since the service is a lightweight, non-nibbed, NSApplication, I was trying to self-terminate it by calling invalidate from inside applicationWillTerminate, but that triggers an EXC_BAD_ACCESS exception almost every time. Calling invalidate on the service's [NSXPCListener serviceListener] generates slightly less reliable crashes, but it still crashes.
Calling invalidate from within the client application on its NSXPCConnection also generates an EXC_BAD_ACCESS exception almost every time.
So I'm curious what the correct sequence of steps is to cleanly shutdown the XPC service and then quit the service application. Ideally, the service would self-terminate after it has made its last XPC call to the client.
Attached is a small screenshot of what one of the exception's stacktrace looks like. (Yes, that's a webview that's loading in the service. Once the webview has finished loading, I want the service to self-terminate)
My first reaction is that you should not bother to terminate. When memory pressure occurs and your service is idle, launchd will kill your service. Exiting probably isn't in anyone's best interest because your service will take time to launch again. Don't terminate and you won't have to figure out why your attempt crashes.
But if for some reason you are determined to terminate, don't try so hard. Just do whatever you need to do to clean up (flush buffers, close network connections gracefully so the server doesn't suffer, whatever) and call exit. Although you seem to be using NSApplication, your service is not an application in any sense that the user cares about and there is no compelling reason to act like one in this respect. The host application needs to be able to cope with your service crashing anyway, so your deliberately exiting unceremoniously is just fine.
By the way, using NSApplication in an XPC service probably isn't the best idea because there's no supported way to declare that you want that. This might help explain why it isn't working as well as you'd like, though this paragraph should not be construed as a proper analysis of the crash. :-)
sc query state= all works as expected from the command line.
From within another Service, sc query state= all doesn't print anything to that sub-process' stdout (captured by the parent, of course).
Is there a permission/privilege that the Service needs in order to list/start/stop the other servies?
A little background: I am making a service that periodically restarts some misbehaving services.
Well, for one don't do that, at least not in a blocking manner. In order for your own service to respond to the SCM (Service Control Manager) in order to return its status, the service has to be able to execute its dispatcher code. This means that if you call this program and wait for it to exit you'll wait indefinitely. One way to mitigate this would be to put this into a separate thread so it's not blocking your dispatching and your service will continue to talk to the SCM.
Alternatively (and probably better) you could use the EnumServicesStatusEx function to talk to the SCM and inquire about the statuses of other services yourself. The function itself doesn't mention anything about being blocking, so you'd have to figure out yourself whether it is and then use a thread again to prevent your service from stopping to talk to the SCM.
One last note: if those misbehaving services are yours, you should more likely fix the respective code. I've had a share of legacy code and had one misbehaving service which got its own helper application as "fault action" (can be configured in service configuration as SERVICE_CONFIG_FAILURE_ACTIONS) that would go about and restart the service whenever it crashed. Once I took that code over, figured out the cause and fixed it, the service was stable again and that application isn't really needed anymore.
I have a C++ Windows application that was designed to be a Windows service. It executes an updater periodically to see if there's a new version. To execute the updater, _execv() is used. The updater looks for new versions, downloads them and stops the Windows service (all of these actions are logged), replaces the files, and starts the service again. Doing that in CLI mode (not going into service mode) works fine that way. According to my log files, the child process is launched, but the parent process (the Windows service) exits.
Is it even "allowed" to launch child processes in Windows services, and, why does the service exit unexpected then? My log files show no error (I am even monitoring for segfaults etc which is written to the log).
Why are you using _execv() rather than doing it the windows way and using CreateProcess()?
I assume you've put some debug into your service and you aren't getting past the point where you call _execv() in your service?
_execv replaces the existing process with a new one running the file you pass as the parameter. Under Unix (and similar) that's handled directly/natively. Windows, however, doesn't support that directly -- so it's done by having the parent process exit and arrange for a child process to be started as soon as it does.
IOW, it sounds like _execv is doing exactly what it's designed to -- but in this case, it's probably not what you really want. You can spawn a process from a service, but you generally want to use CreateProcessAsUser to create it under a specified account instead of the service account (which has a rather unusual set of rights assigned to it). The service process will then exit and restart when it's asked to by the service manager when your updater calls ControlService, CreateService, etc.
A consultant setup a windows service to run a application. The application is supposed to run every 15 minutes. The application is not running at all and the service appears to be running fine.
I am not familiar with how an application will run at a standard interval when running as a service.
The service uses the SRVANY.EXE tool.
Any 'consultant' that sets up a service to run using SRVANY.EXE should be fired. SRVANY is an unfortunate hack that should have been retired a decade ago; it should never be used in a production environment.
If the only purpose for the service is to run the app on a schedule then it shouldn't exist at all. Run the app as a Scheduled Task. If it has other functionality then rewrite it as a real service. If it is reasonably well written it should be a fairly easy conversion.
There are many potential issues with your application.
SRVANY.EXE turns any application into a Windows Service. If that application ever asks for user input, it will hang. You will want to confirm that the application running as a service does nothing more than start the other application.
You should also be able to run the "starter" application manually, outside the Windows Service. If it still doesn't work as it should you know it's not related to being run as a service.
To add to the other answers: see KB137890 on what SRVANY.EXE actually does and how to find out what application it is running.
It seems to me that you would be better off (if you can) setting up a scheduled task that runs every the application every 15 minutes if you can.
I'm not sure if this is correct, but I believe one way of a serivce running an application is merely to have a thread within OnStart and set it to run the application on an invertal of 15 minutes.