init.d script for Debian GNU/Linux to run multiple Django instances, each in it's own virtualenv, with gunicorn.

django_gunicorn

#! /bin/sh
### BEGIN INIT INFO
# Provides:          gunicorn_django
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Gunicorn WSGI server for django
# Description:       This script starts a gunicorn instance for each django instance
### END INIT INFO

# Author: Elmar Athmer <elmar@nixus-minimax.de>

# Do NOT "set -e"

# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/sbin:/usr/sbin:/bin:/usr/bin
DESC="Gunicorn WSGI Server"
NAME=gunicorn_django
#DAEMON=/usr/sbin/$NAME
#DAEMON_ARGS="--options args"
#PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME

# Exit if the package is not installed
#[ -x "$DAEMON" ] || exit 0

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.2-14) to ensure that this file is present
# and status_of_proc is working.
. /lib/lsb/init-functions

# function that set all vars needed to start an instance
set_vars_for_instance() 
{
                if [ -d $1 ]
                then
                                FULLPATH=$1
                else
                                FULLPATH="${PREFIX}/$1"
                fi
                INSTANCE_NAME=`basename $1`
                SETTINGS=`find $FULLPATH -maxdepth 2 -name settings.py`
                DAEMON="${FULLPATH}/bin/$NAME"
                PIDFILE="/var/run/gunicorn/${INSTANCE_NAME}.pid" # maybe we could deduce the pidfile from the gunicorn config?
                CONFIGFILE="/etc/gunicorn/${INSTANCE_NAME}.py"
                DAEMON_ARGS="-D -c $CONFIGFILE $SETTINGS"
}

# to control single instances with e.g. $SCRIPTNAME start myproject
[ -n "$2" ] && INSTANCES=$2

#
# Function that starts the daemon/service
#
do_start()
{
                # Return
                #   0 if daemon has been started
                #   1 if daemon was already running
                #   2 if daemon could not be started
                for i in $INSTANCES
                do
                                set_vars_for_instance $i

                                # we let gunicorn switch the user, so check if the configfile has an user defined
                                if [ -e $CONFIGFILE ] && /usr/bin/env python -B -c "import imp;import sys;c = imp.load_source('config', '${CONFIGFILE}');sys.exit(0 if hasattr(c, 'user') else 1)" &> /dev/null
                                then
                                                start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null # || return 1
                                                start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \
                                                                $DAEMON_ARGS # || return 2
                                else
                                                echo "No user defined in $CONFIGFILE/configfile not found, not starting $INSTANCE_NAME"
                                fi
                done
}

#
# Function that stops the daemon/service
#
do_stop()
{
                for i in $INSTANCES
                do
                                set_vars_for_instance $i

                                # Return
                                #   0 if daemon has been stopped
                                #   1 if daemon was already stopped
                                #   2 if daemon could not be stopped
                                #   other if a failure occurred
                                start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE # --name $NAME
                                #RETVAL="$?"
                                #[ "$RETVAL" = 2 ] && return 2

                                rm -f $PIDFILE
                                #return "$RETVAL"
                done
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
        for i in $INSTANCES
        do
                        set_vars_for_instance $i
                        kill -HUP `cat $PIDFILE`
        done
}

case "$1" in
  start)
        [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
        do_start
        case "$?" in
                0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
                2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        ;;
  stop)
        [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
        do_stop
        case "$?" in
                0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
                2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
        esac
        ;;
  status)
       status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
       ;;
  reload|force-reload)
        log_daemon_msg "Reloading $DESC" "$NAME"
        do_reload
        log_end_msg $?
        ;;
  restart|force-reload)
        #
        # If the "reload" option is implemented then remove the
        # 'force-reload' alias
        #
        log_daemon_msg "Restarting $DESC" "$NAME"
        do_stop
        case "$?" in
          0|1)
                do_start
                case "$?" in
                        0) log_end_msg 0 ;;
                        1) log_end_msg 1 ;; # Old process is still running
                        *) log_end_msg 1 ;; # Failed to start
                esac
                ;;
          *)
                # Failed to stop
                log_end_msg 1
                ;;
        esac
        ;;
  *)
        echo "Usage: $SCRIPTNAME {start|stop|status|restart|reload|force-reload} myisntance" >&2
        exit 3
        ;;
esac