I have a small web server application I've written in Python that goes and gets some data from a database system and returns it to the user as XML. That part works fine - I can run the Python web server application from the command line and I can have clients connect to it and get data back. At the moment, to run the web server I have to be logged in to our server as the administrator user and I have to manually start the web server. I want to have the web server automatically start on system start as a service and run in the background.
Using code from ActiveState's site and StackOverflow, I have a pretty good idea of how to go about creating a service, and I think I've got that bit sorted - I can install and start my web server as a Windows service. I can't, however, figure out how to stop the service again. My web server is created from a BaseHTTPServer:
The serve_forever() call, naturally enough, makes the web server sit in an infinite loop and wait for HTTP connections (or a ctrl-break keypress, not useful for a service). I get the idea from the example code above that your main() function is supposed to sit in an infinite loop and only break out of it when it comes accross a "stop" condition. My main calls serve_forever(). I have a SvcStop function:Code:server = BaseHTTPServer.HTTPServer(('', 8081), SIMSAPIServerHandler) server.serve_forever()
Which seems to get called when I do "python myservice stop" from the command line (I can put a debug line in there that produces output to a file) but doesn't actually exit the whole service - subsequent calls to "python myservice start" gives me an error:Code:def SvcStop(self): self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING) exit(0)
and subsequent calls to stop gives me:Error starting service: An instance of the service is already running.
I think I need either some replacement for serve_forever (serve_until_stop_received, or whatever) or I need some way of modifying SvcStop so it stops the whole service.Error stopping service: The service cannot accept control messages at this time. (1061)
Here's a full listing (I've trimmed includes/comments to save space):
--Code:class SIMSAPIServerHandler(BaseHTTPServer.BaseHTTPRequestHandler): def do_GET(self): try: reportTuple = self.path.partition("/") if len(reportTuple) < 3: return if reportTuple == "": return os.system("C:\\Programs\\SIMSAPI\\runCommandReporter.bat " + reportTuple) f = open("C:\\Programs\\SIMSAPI\\out.xml", "rb") self.send_response(200) self.send_header('Content-type', "application/xml") self.end_headers() self.wfile.write(f.read()) f.close() # The output from CommandReporter is simply dumped to out.xml, which we read, write to the user, then remove. os.unlink("C:\\Programs\\SIMSAPI\\out.xml") return except IOError: self.send_error(404,'File Not Found: %s' % self.path) class SIMSAPI(win32serviceutil.ServiceFramework): _svc_name_ = "SIMSAPI" _svc_display_name_ = "A simple web server" _svc_description_ = "Serves XML data produced by SIMS CommandReporter" def __init__(self, args): win32serviceutil.ServiceFramework.__init__(self, args) self.hWaitStop = win32event.CreateEvent(None, 0, 0, None) def SvcStop(self): self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING) exit(0) def SvcDoRun(self): import servicemanager servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE,servicemanager.PYS_SERVICE_STARTED,(self._svc_name_, '')) self.timeout = 3000 while 1: server = BaseHTTPServer.HTTPServer(('', 8081), SIMSAPIServerHandler) server.serve_forever() def ctrlHandler(ctrlType): return True if __name__ == '__main__': win32api.SetConsoleCtrlHandler(ctrlHandler, True) win32serviceutil.HandleCommandLine(SIMSAPI)
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