Re: Re: PyDS as a service

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"""
PyDS as a NT service.

This script is based on the ZService.py script from the Zope
distribution. Thanks to the Zope Corp for this little gem.

The service starts up and monitors a PyDS process.

Features:
  
  * When you start the service it starts PyDS
  * When you stop the serivice it stops PyDS
  * It monitors PyDS and restarts it if it exits abnormally
  * If PyDS is shutdown from the web, the service stops.
  * If PyDS cannot be restarted, the service stops.

Usage:

  Installation
  
    You can manually install, uninstall the service from
    the commandline.
    
      PyDS-win32.py [options] install|update|remove|start [...]
          |stop|restart [...]|debug [...]

    Options for 'install' and 'update' commands only:
    
     --username domain\username : The Username the service is to run
                                  under
     
     --password password : The password for the username
     
     --startup [manual|auto|disabled] : How the service starts, 
                                        default = manual
  
    Commands
           
      install : Installs the service
     
      update : Updates the service, use this when you update
               PyDS
     
      remove : Removes the service
     
      start : Starts the service, this can also be done from the
              services control panel
     
      stop : Stops the service, this can also be done from the
             services control panel
     
      restart : Restarts the service
     
      debug : Runs the service in debug mode
  
  Starting PyDS
  
    Start PyDS by clicking the 'start' button in the services control
    panel. You can set PyDS to automatically start at boot time by
    choosing 'Auto' startup by clicking the 'statup' button.
  
  Stopping PyDS
  
    Stop PyDS by clicking the 'stop' button in the services control
    panel. You can also stop PyDS through the web by going to the
    PyDS control panel and by clicking 'Shutdown'. 
  
  Event logging
  
    Service events are logged to the NT application event log. Use the
    event viewer to keep track of service events.

  Registry Settings
  
    You can change how the service starts PyDS by editing a registry
    key.
    
      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
        <Service Name>\Parameters\start

    The value of this key is the command which the service uses to
    start PyDS. For example:
    
      "C:\Program Files\Python\python.exe"
        "C:\Program Files\Python\bin\pyds-start" -v

    
This script does for NT the same sort of thing zdaemon.py does for UNIX.
Requires Python win32api extensions.
"""
import sys, os, string, time, imp

# Some fancy path footwork is required here because we
# may be run from python.exe or lib/win32/PythonService.exe

home=os.path.split(os.path.split(sys.executable)[0])[0]
if sys.executable[-10:]!='python.exe':
    home=os.path.split(home)[0]
    home=os.path.split(home)[0]
sys.path.append(os.path.join(home, 'bin'))
sys.path.append(os.path.join(home, 'bin', 'lib', 'win32'))
sys.path.append(os.path.join(home, 'bin', 'lib', 'win32', 'lib'))


# pythoncom and pywintypes are special, and require these hacks when
# we dont have a standard Python installation around.

import win32api
def magic_import(modulename, filename):
    # by Mark Hammond
    try:
        # See if it does import first!
        return __import__(modulename)
    except ImportError:
        pass
    # win32 can find the DLL name.
    h = win32api.LoadLibrary(filename)
    found = win32api.GetModuleFileName(h)
    # Python can load the module
    mod = imp.load_module(modulename, None, found, ('.dll', 'rb', imp.C_EXTENSION))
    # inject it into the global module list.
    sys.modules[modulename] = mod
    # And finally inject it into the namespace.
    globals()[modulename] = mod
    win32api.FreeLibrary(h)

magic_import('pywintypes','pywintypes21.dll')

import win32serviceutil, win32service, win32event, win32process
try: import servicemanager
except: pass

class PyDSService(win32serviceutil.ServiceFramework):

    # Some trickery to determine the service name. The WISE
    # installer will write an svcname.txt to the PyDS dir
    # that we can use to figure out our service name.

    _svc_name_ = 'PyDS'
    _svc_display_name_ = "Python Desktop Server (%s)" % _svc_name_
    
    restart_min_time=5 # if the server restarts before this many
                       # seconds then we have a problem, and
                       # need to stop the service.
    
    def __init__(self, args):
        win32serviceutil.ServiceFramework.__init__(self, args)
        self.hWaitStop = win32event.CreateEvent(None, 0, 0, None)
    
    def SvcDoRun(self):
        self.start_zserver()
        while 1:
            rc=win32event.WaitForMultipleObjects(
                    (self.hWaitStop, self.hPyDS), 0, win32event.INFINITE)
            if rc - win32event.WAIT_OBJECT_0 == 0:
                break
            else:
                self.restart_zserver()
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING, 5000)   

    def SvcStop(self):
        servicemanager.LogInfoMsg('Stopping PyDS.') 
        try:
            self.stop_zserver()              
        except:
            pass
        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        win32event.SetEvent(self.hWaitStop)

    def start_zserver(self):
        sc=self.get_start_command()
        result=win32process.CreateProcess(None, self.get_start_command(),
                None, None, 0, 0, None, None, win32process.STARTUPINFO())
        self.hPyDS=result[0]
        self.last_start_time=time.time()
        servicemanager.LogInfoMsg('Starting PyDS.')
        
    def stop_zserver(self):
        win32process.TerminateProcess(self.hPyDS,0)
        
    def restart_zserver(self):
        if time.time() - self.last_start_time < self.restart_min_time:
            servicemanager.LogErrorMsg('PyDS died and could not be restarted.')
            self.SvcStop()
        code=win32process.GetExitCodeProcess(self.hPyDS)
        if code == 0:
            # Exited with a normal status code,
            # assume that shutdown is intentional.
            self.SvcStop()
        else:
            servicemanager.LogWarningMsg('Restarting PyDS.')
            self.start_zserver()

    def get_start_command(self):
        return win32serviceutil.GetServiceCustomOption(self,'start')
        
        
def set_start_command(value):
    "sets the PyDS start command if the start command is not already set"
    current=win32serviceutil.GetServiceCustomOption(PyDSService,
                                                    'start', None)
    if current is None:
        win32serviceutil.SetServiceCustomOption(PyDSService,'start',value)
        return 1
    return 0
            

if __name__=='__main__':
    win32serviceutil.HandleCommandLine(PyDSService)
    if 'install' in sys.argv:
        command='"%s" "%s"' % (sys.executable, os.path.join(os.path.dirname(sys.executable), 'scripts', 'pyds-start'))
        if set_start_command(command):
            print "Setting PyDS start command to:", command