Re: daemonizing a command

[Ron Johnson <ron.l.johnson@cox.net>]

On 05/27/2010 02:52 PM, Israel Garcia wrote:
> Hi,
>
> I need to daemonize this command on a debian lenny?
>
> ruby apd.rb
>
> It's a simple app for my network.
>
> I was thinking to use nohup ruby app.rb&  at rc.local, but I want to
> know if there's other ways to do it.

Using Python, I create a module named daemonize and then at the 
beginning of any program I want to run as a daemon, I do:
import daemonize
daemonize.daemonize()

Maybe you can convert this code to Ruby...

#  Daemon Module - basic facilities for becoming a daemon process
#  written by  Coy Krill (ckrill@qvlinc.com)
#
#  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()


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