Is it possible to subclass a subclass of win32serviceutil.ServiceFramework?

Question

I have a few services and I wanted to make a shared base class for them... however when I install a test subclass service, it fails with a useless error.

Here is the code:

import servicemanager
import win32serviceutil
import sys
import win32service
import win32event

class PythonServiceBase(win32serviceutil.ServiceFramework):
    _svc_name_ = "SmallestPythonService"
    _svc_display_name_ = "The smallest possible Python Service"
    def __init__(self, args):
        win32serviceutil.ServiceFramework.__init__(self, args)
        # Create an event which we will use to wait on.
        # The "service stop" request will set this event.
        self.hWaitStop = win32event.CreateEvent(None, 0, 0, None)

    def SvcStop(self):
        # Before we do anything, tell the SCM we are starting the stop process.
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        # And set my event.
        win32event.SetEvent(self.hWaitStop)

    def SvcDoRun(self):
        # We do nothing other than wait to be stopped!
        win32event.WaitForSingleObject(self.hWaitStop, win32event.INFINITE)


class BaselineService(PythonServiceBase):
    _svc_name_ = "SmallestPythonService2"
    _svc_display_name_ = "The smallest possible Python Service2"
    def __init__(self, args):
        super(BaselineService, self).__init__(args)


if __name__ == '__main__':
    if len(sys.argv) == 1:
        servicemanager.Initialize()
        servicemanager.PrepareToHostSingle(BaselineService)
        servicemanager.StartServiceCtrlDispatcher()
    else:
        win32serviceutil.HandleCommandLine(BaselineService)

Here's how I create and install:

pyinstaller -F --debug --hidden-import=win32timezone Baseline\baseline_service.py

dist\baseline_service.exe install && net start SmallestPythonService2

There are no tracebacks in the CMD output but this shows up:

The The smallest possible Python Service2 service is starting.
The The smallest possible Python Service2 service could not be started.

A service specific error occurred: 1.

More help is available by typing NET HELPMSG 3547.

Inside Event Viewer I see this:

- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
  <Provider Name="Python Service" /> 
  <EventID Qualifiers="49152">10</EventID> 
  <Level>2</Level> 
  <Task>0</Task> 
  <Keywords>0x80000000000000</Keywords> 
  <TimeCreated SystemTime="2019-01-17T22:43:16.954038000Z" /> 
  <EventRecordID>76457</EventRecordID> 
  <Channel>Application</Channel> 
  <Computer>DESKTOP-IM94TC5</Computer> 
  <Security /> 
  </System>
- <EventData>
  <Data><Error getting traceback - traceback.print_exception() failed</Data> 
  </EventData>
  </Event>

Is pyinstaller just not capable of accurately passing subclass behavior to the EXE context?

If so, what are the pros/cons of the following alternative strategies:

1. Importing all shared methods from a "ServiceUtil" module to be used with my various services

2. Running a "ServiceHelper" on the same machine on which the true services run, and on __init__ for each service, thy would consult this ServiceHelper to get back their shared behaviors (like the DoRun and Stop methods, etc.)

Answer 1

Doh! Here was the issue:

Instead of calling (this only works for Python 2):

super(BaselineService, self).__init__(args)

...I called the parent class directly and it worked:

PythonServiceBase.__init__(self, args)

This works also (I wasn't calling super properly. Python 3 only):

super().__init__(args)

Source : Python extending with - using super() Python 3 vs Python 2