memcached service for windows

memcached_service.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Attribution: Hijacked from tracservice.py by Florent Xicluna <laxyf@yahoo.fr>
# http://trac-hacks.org/wiki/WindowsServiceScript
#
# To use this class, users must do the following:
# 1. Download and install the PyWin32all package
#    (http://starship.python.net/crew/mhammond/win32/)
# 2. Edit the constants section with the proper information.
# 3. Open a command prompt with administrator rights and navigate to the directory
#    where this file is located.  Use one of the following commands to
#    install/start/stop/remove the service:
#    > memcached_service.py install
#    > memcached_service.py start
#    > memcached_service.py stop
#    > memcached_service.py remove
#    Additionally, typing "memcached_service.py" will present the user with all of the
#    available options.
#
# Once installed, the service will be accessible through the Services
# management console just like any other Windows Service.  All service 
# startup exceptions encountered by the MemcachedWindowsService class will be 
# viewable in the Windows event viewer (this is useful for debugging
# service startup errors); all application specific output or exceptions that
# are not captured by the standard memcached logging mechanism should 
# appear in the stdout/stderr logs.
#

import os
import subprocess
import json
import win32serviceutil
import win32service
import win32event
import logging

MEMCACHED_OPTS_FILE = 'memcached_opts.json'
MEMCACHED_EXE = 'memcached.exe'
MEMCACHED_LOG = 'memcache.log'
DIRNAME = os.path.dirname(__file__)
logging.basicConfig(filename=os.path.join(DIRNAME, MEMCACHED_LOG),
    level=logging.DEBUG, format='[%(asctime)s] %(levelname)s: %(message)s')
MEMCACHED = os.path.join(DIRNAME, MEMCACHED_EXE)
OPTS_FILE = os.path.join(DIRNAME, MEMCACHED_OPTS_FILE)
if os.path.exists(OPTS_FILE):
    with open(OPTS_FILE, 'r') as opts_file:
        OPTS = json.load(opts_file)

# memcached args
ARGS = [MEMCACHED]
# ARGS += [arg for key_val in OPTS.iteritmes() for arg in key_val]

class MemcachedWindowsService(win32serviceutil.ServiceFramework):
    """memcached Windows Service helper class.

    The MemcachedWindowsService class contains all the functionality required
    for running memcached application as a Windows Service.

    For information on installing the application, please refer to the
    documentation at the end of this module or navigate to the directory
    where this module is located and type "memcached_service.py" from the
    command prompt.
    """

    _svc_name_ = 'memcached'
    _svc_display_name_ = 'memcached server at %s' % MEMCACHED

    def __init__(self, args):
        win32serviceutil.ServiceFramework.__init__(self, args)
        # create an event that SvcDoRun can wait on and SvcStop
        # can set.
        self.stop_event = win32event.CreateEvent(None, 0, 0, None)

    def SvcDoRun(self):
        """ Called when the Windows Service runs. """

        self.ReportServiceStatus(win32service.SERVICE_START_PENDING)
        try:
            self.popen = subprocess.Popen(ARGS)
        except Exception as err:
            logging.debug('%s', err.message)            
            raise err
        if not self.popen.returncode:
            logging.debug('memcached service started on PID: %d',
                          self.popen.pid)
        else:
            logging.debug('memcached service failed to start')
            
        self.ReportServiceStatus(win32service.SERVICE_RUNNING)
        # now, block until our event is set...
        win32event.WaitForSingleObject(self.stop_event, win32event.INFINITE)

    def SvcStop(self):
        """Called when Windows receives a service stop request."""

        self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
        self.popen.kill()
        logging.debug('memcached service stopped on PID: %d', self.popen.pid)
        
        self.ReportServiceStatus(win32service.SERVICE_STOPPED)
        win32event.SetEvent(self.stop_event)


if __name__ == '__main__':
    # The following are the most common command-line arguments that are used
    # with this module:
    #  memcached_service.py install (Installs the service with manual startup)
    #  memcached_service.py --startup auto install (Installs the service with auto startup)    
    #  memcached_service.py start (Starts the service)
    #  memcached_service.py stop (Stops the service)
    #  memcached_service.py remove (Removes the service)
    #
    # For a full list of arguments, simply type "memcached_service.py".
    win32serviceutil.HandleCommandLine(MemcachedWindowsService)