bus deadlock joining main thread

[ghost]

Originally reported by: Alexey Luchko (Bitbucket: soulne4ny, GitHub: soulne4ny)

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Hi!

I had to make custom win32 service running cherrypy.
While debugging it found that at cherrypy.engine.exit() it hands waiting something (for multiple objects). Log contained "Waiting for thread MainThread." I found Bus.block() waiting for all non-daemon threads at exit.

A workaround could be either tweaking threading.enumerate() before calling engine.exit() or making main thread daemon.

A possible patch attached.

Regards,
Alex

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• Bitbucket: https://bitbucket.org/cherrypy/cherrypy/issue/1164

[ghost]

Original comment by Joel Rivera (Bitbucket: cyraxjoe, GitHub: cyraxjoe):

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I have just experience exactly the same issue and you are right, the thread that execute SvcStop is not the main thread as a work around tried to communicate trough an event and it worked:

#!python
    def SvcDoRun(self):
        import servicemanager
        servicemanager.LogMsg(
               servicemanager.EVENTLOG_INFORMATION_TYPE,
               servicemanager.PYS_SERVICE_STARTED,
               (self._svc_name_, ''))
        SITE.web.start(block=False)
        win32event.WaitForSingleObject(self.stop_event, win32event.INFINITE)
        SITE.web.stop()

    def SvcStop(self):
        import servicemanager
        servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE,
                              servicemanager.PYS_SERVICE_STOPPED,
                              (self._svc_name_, ''))
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        win32event.SetEvent(self.stop_event)

Anyway I think that your patch will be an improvement for this case and at the same time fix the issue #1101.

[ghost]

Original comment by Joel Rivera (Bitbucket: cyraxjoe, GitHub: cyraxjoe):

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Bugfix of a potential deadlock if the main bus is stopped from a different
thread than the main thread, this is the case when is implemented as a
windows service.

Closing issue #1164
Closing issue #1101