#!/usr/bin/env python

#coding:utf8

import sys, os

def main():

    """ A demo daemon main routine, write a datestamp to

        /tmp/daemon-log every 10 seconds.

    """

    import time

    f = open("/tmp/daemon-log", "w")

    while 1:

        f.write('%s/n' % time.ctime(time.time()))

        f.flush()

        time.sleep(10)

if __name__ == "__main__":

    # do the UNIX double-fork magic, see Stevens' "Advanced

    # Programming in the UNIX Environment" for details (ISBN 0201563177)

    try:

        pid = os.fork()

        if pid > 0:

            # exit first parent

            sys.exit(0)

    except OSError, e:

        print >>sys.stderr, "fork #1 failed: %d (%s)" % (e.errno, e.strerror)

        sys.exit(1)

    # decouple from parent environment

    os.chdir("/")

    os.setsid()

    os.umask(0)

    # do second fork

    try:

        pid = os.fork()

        if pid > 0:

            # exit from second parent, print eventual PID before

            print "Daemon PID %d" % pid

            sys.exit(0)

    except OSError, e:

        print >>sys.stderr, "fork #2 failed: %d (%s)" % (e.errno, e.strerror)

        sys.exit(1)

    # start the daemon main loop

    main()