redirecting sdtout/sdterr in a daemon

Rajarshi Guha rxg218 at psu.edu
Tue Oct 30 17:01:09 CET 2001


Hi,
  I'm using the daemonize.py module to make my code run as a daemon. 
However the module contains the lines:

sys.stdout = NullDevice()
sys.stderr = NullDevice()

Instead of this behaviour I would like it to write output to a file. So I 
write:

sys.stderr = open(outputhandle,'w')
sys.stdout = open(outputhandle,'w')

Where outputhandl is a passed to the function. However no output comes to 
the this file. In addition when i try and print anything from the function, 
nothing is output.

How can I fix this problem. Below is the code for daemonize.py:
----------------------------------------------------------------------
def become_daemon(ourHomeDir='.'):
        """Robustly turn us into a UNIX daemon, running in ourHomeDir.
        XXX on SVR4 some claim you should re-fork after the setsid()
        jjk  06/25/97  001
        """
        import os
        import sys
        if os.fork() != 0:  # launch child and...
                os._exit(0)     # kill off parent
        os.setsid()
        os.chdir(ourHomeDir)
        os.umask(0)
        sys.stdin.close()
        #sys.stdout.close()
        #sys.stderr.close()
        sys.stdout = NullDevice()
        sys.stderr = NullDevice()
        for z in range(3, 256):
                try: os.close(z)
                except: pass

class NullDevice:
        """A substitute for stdout and stderr that writes to nowhere
        jjk  06/25/97  001
        """

        def write(self, s):
                """accept a write command, but do nothing
                jjk  06/25/97  001
                """
                pass

-- 
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Rajarshi Guha                  | email: rajarshi at presidency.com
152 Davey Laboratory           | web  : www.rajarshi.outputto.com 
Department of Chemistry        | ICQ  : 123242928
Pennsylvania State University  | AIM  : LoverOfPanda
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