Hello there, I currently have a little project which involve the writing of a server that launch tasks when requested by the user (through a web interface for instance).
I would like to turn my server script into a Linux/Unix daemon (launched at boot time by init, dunno if that matter) using the nice python-daemon package by Ben Finley et al (http://pypi.python.org/pypi/ python-daemon/). This package comes with a class DaemonRunner that seems to fit almost exactly my need but I still have some interrogation. My main class looks like the following: class SIGTERM_Received(Exception): pass class MyDaemon(object): def __init__(self): self.pidfile = '/path/to/the/file' self.pidfile_timeout = 5 self.stdin_path = None self.stdout_path = None self.stderr_path = None def run(self): self.init() self.main_loop() self.terminate() def init(self): #doing some initialisation here eg: database connection, logging, connection establishing and such... signal.signal (signal.SIGTERM, lambda: raise SIGTERM_Received()) # used to interrupt the connection listening loop def main_loop(self): #This is the "server" loop try: while True: rcv = self.some_connection.receive() # this may hang until something was written into the connection by a client. # do something with rcv that involving processes spawning, database interaction and so on... except SIGTERM_Received: return def terminate(self): #some clean up like connection closing and child processes joining. pass And this is the script I intend to drop into /etc/rc.d (for an Archlinux-style initd): #! /usr/bin/python from daemon.runner import DaemonRunner from foo import MyDaemon daemon_runner = DaemonRunner(MyDaemon()) daemon_runner.parse_args() daemon_runner.do_action() The DaemonRunner class expects my class to have stdin_path, stdout_path, stderr_path attributes and after reading the code it seems they have to be valid paths. Is that ok for a Daemon to redirect those stream to /dev/null for example ? I would prefer to alter the DaemonRunner class to accept None as value since DaemonContext, the underlying class, seems to accept None for those parameters. Also, the DaemonRunner use os.kill(pid, signal.SIGTERM) to stop the daemon. I wonder if with my signal handling I'll be able to terminate correctly the daemon (joining children, flushing buffers, closing connections...). If that's relevant, the connection I use is a Listener/Client connection from the standard multiprocessing module. I'm quite neophyte in Unix daemon programming so please forgive me if my question are obvious. Thank for reading, Thomas -- http://mail.python.org/mailman/listinfo/python-list
