Implemented proper daemonization in server.

#!/usr/bin/env python

#coding=utf8

import os

import sys

import atexit

import logging

import logging.handlers

import ConfigParser

import signal

from optparse import OptionParser

from pwd import getpwnam

from grp import getgrnam

from daemon import DaemonContext

from daemon.pidlockfile import PIDLockFile

from ccserver.ccserver import CCServer

from ccserver import __version__

import os

try:

    import daemon

    DAEMONIZE = True

except ImportError:

    DAEMONIZE = False

DEFAULT_CONFIG_FILE = '/etc/cc-server.conf'

DEFAULT_PID_FILE = '/var/run/cc-server.pid'

DEFAULT_UMASK = 0o0177

DEFAULT_CONFIGURATION = {

    'daemonize': False,

    'user': '',

    'group': '',

    'pidfile': '',

    'umask': '0177',

    'port': 1984,

    'verbosity': 0,

    'account_db': None, # None = mandatory option

    logger = logging.getLogger()

    logger.setLevel(level)

    if options['stdout']:

        handler = logging.StreamHandler()

    else:

        facility = logging.handlers.SysLogHandler.LOG_DAEMON

        handler = logging.handlers.SysLogHandler(address='/dev/log',

                                                 facility=facility)

    fmt = logging.Formatter('cc-server: %(levelname)s %(message)s')

    handler.setFormatter(fmt)

    logger.addHandler(handler)

    op = OptionParser(version='%%prog v%s' % __version__)

    op.add_option('-c', '--config', default=DEFAULT_CONFIG_FILE,

                  help='configuration file (default: %default)')

    op.add_option('-d', '--daemonize', default=False, action='store_true',

                  help='run as daemon and write pid file')

    op.add_option('-p', '--pid-file', default=DEFAULT_PID_FILE,

                  help='pid file (default: %default)')

    op.add_option('-d', '--daemonize', action='store_true',

                  help='run as a daemon')

    op.add_option('-f', '--foreground', action='store_false', dest='daemonize',

                  help='don\'t run as a daemon')

    op.add_option('-p', '--pidfile', help='write pidfile to the path')

    op.add_option('-k', '--umask', help='set the umask of the process')

    op.add_option('-u', '--user', help='run as user')

    op.add_option('-g', '--group', help='run as group')

    op.add_option('-s', '--stdout', action='store_true', default=False,

                  help='log in stdout instead of syslog')

    cliopts, args = op.parse_args()

            else:

                options[opt] = default

    if cliopts.daemonize:

        if DAEMONIZE:

            with daemon.DaemonContext(stderr=sys.stderr):

                run_server(options)

    # Merge cli options and .conf file options:

    for opt in ('daemonize', 'pidfile', 'umask', 'user', 'group', 'stdout'):

        if getattr(cliopts, opt) is not None:

            options[opt] = getattr(cliopts, opt)

    # Create option set for the daemonization process:

    daemon_opts = {}

    daemonize = options['daemonize']

    if isinstance(daemonize, str):

        if daemonize in ('yes', 'true'):

            daemonize = True

        else:

            daemonize = False

    daemon_opts['detach_process'] = daemonize

    daemon_opts['umask'] = int(options['umask'], 8)

    if options['user']:

        if options['user'].isdigit():

            daemon_opts['uid'] = int(options['user'])

        else:

            daemon_opts['uid'] = getpwnam(options['user']).pw_uid

    if options['group']:

        if options['group'].isdigit():

            daemon_opts['gid'] = int(options['group'])

        else:

            sys.stderr.write(('You must install python-daemon to handle the '

                              'daemonization of the process.\n'))

            sys.exit(2)

            daemon_opts['gid'] = getgrnam(options['group']).gr_gid

    if not daemonize:

        daemon_opts['stderr'] = sys.stderr

        daemon_opts['stdout'] = sys.stderr

    # I've to write myself the pidfile because the daemon library write it

    # after the privilege downgrade:

    if options['pidfile']:

        pidfile = open(cliopts.pidfile, 'w')

        daemon_opts['files_preserve'] = [pidfile]

    else:

        pidfile = None

    with DaemonContext(**daemon_opts):

        if pidfile is not None:

            pidfile.write('%s' % os.getpid())

            pidfile.flush()

            @atexit.register

            def clean_pidfile():

                pidfile.seek(0)

                pidfile.truncate()

                pidfile.flush()

        run_server(options)

DESC="CloudControl server"

NAME=cc-server

DAEMON=/usr/bin/cc-server

DAEMON_ARGS=""

PIDFILE=/var/run/$NAME.pid

# Defaults:

USER=cc-server

GROUP=cc-server

DAEMON_OPTS="-d -p $PIDFILE"

# Exit if the package is not installed

[ -x "$DAEMON" ] || exit 0

#

do_start()

{

    start-stop-daemon --start --quiet --background --name $NAME -k 0177 \

    start-stop-daemon --start --quiet --background --name $NAME \

            --exec $(readlink -f $(which python)) --test > /dev/null || return 2

    start-stop-daemon --start --quiet --background --make-pidfile \

            --pidfile $PIDFILE --chuid $USER:$GROUP --exec $DAEMON \

    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON \

            -- $DAEMON_OPTS || return 1

}