daemon.py

import os
import subprocess
import logging
import argparse

''' Make a python script as daemon. 
	Usage:
		python daemon.py start|stop|restart
	You can use this for some scenes such as subversion hooks or init.d

'''



START_STOP_DAEMON = '/sbin/start-stop-daemon'
INTERPRETER = '/usr/bin/python'
SCRIPT = 'your-python-script-absolute-path'
PID_FILE = '/var/run/your-proejct.pid'

LOG_NAME = 'project-name'
LOG_FILE = '/var/log/yourproject.log'
LOG_DEBUG_FILE = '/var/log/yourproject-debug.log'

def getLogger():
	logger = logging.getLogger(LOG_NAME)
	ih = logging.FileHandler(LOG_FILE)
	dh = logging.FileHandler(LOG_DEBUG_FILE)
	ih.setLevel(logging.INFO)
	dh.setLevel(logging.DEBUG)
	logger.addHandler(ih)
	logger.addHandler(dh)
	logger.setLevel(logging.DEBUG)
	return logger

logger = getLogger()


def start_server():
	logger.debug('start..')

	try:
		subprocess.check_call([START_STOP_DAEMON, 
			'--start', 
			'--background', 
			'--pidfile', PID_FILE,
			'--make-pidfile',
			'--exec', INTERPRETER,
			'--', SCRIPT])


	except subprocess.CalledProcessError as e:
		logger.error('error code: ' + str(e.returncode))
		logger.error('error output: ' + str(e.output))



def stop_server():
	logger.debug('stop..')

	try:
		subprocess.check_call([START_STOP_DAEMON,
			'--stop',
			'--pidfile', PID_FILE])

		os.remove(PID_FILE)
		logger.debug('remove: ' + PID_FILE)

	except subprocess.CalledProcessError as e:
		logger.error('error code: ' + str(e.returncode))
		logger.error('error output: ' + str(e.output))


def restart_server():
	stop_server()
	start_server()


def main():
	parser = argparse.ArgumentParser()
	parser.add_argument('act', action='store')
	action = vars(parser.parse_args())['act']

	if action == 'start':
		start_server()
	elif action == 'stop':
		stop_server()
	elif action == 'restart':
		restart_server()


if __name__ == '__main__':
	main()