Creating a daemon process in Python

[Eirikur Hallgrimsson]

Sakagami Hiroki wrote:
> Hi,
>
> What is the easiest way to create a daemon process in Python?
I find that this works great.  I just pasted my copy, I think you can 
find it via Google.

Eirikur


#  Daemon Module - basic facilities for becoming a daemon process
#  By Coy Krill
#  Combines ideas from Steinar Knutsens daemonize.py and
#  Jeff Kunces demonize.py

"""Facilities for Creating Python Daemons"""

import os
import time
import sys

class NullDevice:
    def write(self, s):
        pass

def daemonize():
    if (not os.fork()):
        # get our own session and fixup std[in,out,err]
        os.setsid()
        sys.stdin.close()
        sys.stdout = NullDevice()
        sys.stderr = NullDevice()
        if (not os.fork()):
            # hang around till adopted by init
            ppid = os.getppid()
            while (ppid != 1):
                time.sleep(0.5)
                ppid = os.getppid()
        else:
            # time for child to die
            os._exit(0)
    else:
        # wait for child to die and then bail
        os.wait()
        sys.exit()