python实现的守护进程(Daemon)用法实例

def createDaemon():
  "'Funzione che crea un demone per eseguire un determinato programma…"'
  import os
  # create - fork 1
  try:
    if os.fork() > 0: os._exit(0) # exit father…
  except OSError,error:
    print 'fork #1 failed: %d (%s)' % (error.errno,error.strerror)
    os._exit(1)
  # it separates the son from the father
  os.chdir('/')
  os.setsid()
  os.umask(0)
  # create - fork 2
  try:
    pid = os.fork()
    if pid > 0:
      print 'Daemon PID %d' % pid
      os._exit(0)
  except OSError,error:
    print 'fork #2 failed: %d (%s)' % (error.errno,error.strerror)
    os._exit(1)
  funzioneDemo() # function demo
def funzioneDemo():
  import time
  fd = open('/tmp/demone.log','w')
  while True:
    fd.write(time.ctime()+'n')
    fd.flush()
    time.sleep(2)
  fd.close()
if __name__ == '__main__':
  createDaemon()