Linux Daemons
some examples that run bots-webserver or jobqueserver as a daemon.
Example1
'I have been starting bots-webserver on my Linux (CentOS) servers via an entry in rc.local and wanted to provide a means to gracefully shut down the process on reboot. There have been other examples of init scripts posted which do the trick, but I wanted to put something together that conformed to LSB. I took an example script I found online and configured it for the bots.webserver process. Since CentOS doesn't handle pid files correctly when using LSB functions, I tweaked it to work around the issue, and it should work on most distributions without a lot of modification.'
### BEGIN INIT INFO
# Provides: bots-webserver
# Required-Start: $remote_fs $network
# Required-Stop: $remote_fs $network
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: BOTS webserver daemon
# Description: BOTS webserver daemon
### END INIT INFO
# Using the lsb functions to perform the operations.
. /lib/lsb/init-functions
# Process name ( For display )
NAME=bots-webserver
# Daemon name, where is the actual executable
DAEMON=/usr/bin/bots-webserver.py
# pid file for the daemon
PIDFILE=/var/run/bots-webserver.pid
# Arguments for the daemon
ARGS="> /dev/null 2>&1 &"
# If the daemon is not there, then exit.
test -x $DAEMON || exit 5
case $1 in
start)
# Checked the PID file exists and check the actual status of process
if [ -e $PIDFILE ]; then
pidofproc -p $PIDFILE $DAEMON && status="0" || status="$?"
# If the status is SUCCESS then don't need to start again.
if [ $status = "0" ]; then
log_success_msg "$NAME process is already running"
exit # Exit
fi
fi
# Start the daemon.
# Start the daemon with the help of start-stop-daemon
# Log the message appropriately
if start_daemon -p $PIDFILE $DAEMON $ARGS; then
# For older LSB functions that don't handle -p argument correctly (i.e. CentOS)
if [ ! -e $PIDFILE ]; then
pidofproc $DAEMON > $PIDFILE
fi
log_success_msg "Starting the process $NAME"
else
log_failure_msg "Failed to start the process $NAME"
fi
;;
stop)
# Stop the daemon.
if [ -e $PIDFILE ]; then
pidofproc -p $PIDFILE $DAEMON > /dev/null && status="0" || status="$?"
if [ "$status" = 0 ]; then
killproc -p $PIDFILE $DAEMON
/bin/rm -f $PIDFILE
log_success_msg "Stoppping the $NAME process"
fi
else
log_warning_msg "$NAME process is not running"
fi
;;
restart)
# Restart the daemon.
$0 stop && sleep 2 && $0 start
;;
status)
# Check the status of the process.
if [ -e $PIDFILE ]; then
pidofproc -p $PIDFILE $DAEMON > /dev/null && log_success_msg "$NAME process is running" && exit 0 || exit $?
else
log_warning_msg "$NAME process is not running"
fi
;;
reload)
# Reload the process. Basically sending some signal to a daemon to reload
# it configurations.
if [ -e $PIDFILE ]; then
killproc -p $PIDFILE $DAEMON -signal USR1
log_success_msg "$NAME process reloaded successfully"
else
log_failure_msg "$PIDFILE does not exists"
fi
;;
*)
# For invalid arguments, print the usage message.
echo "Usage: $0 {start|stop|restart|reload|status}"
exit 2
;;
esac
Example2
Depends on 'start-stop-daemon' , which is used in debian/ubuntu.
#! /bin/sh
#
# uses 'start-stop-daemon' , which is used in debian/ubuntu<br>
#
NAME=bots-webserver
PIDFILE="/var/run/$NAME.pid"
DAEMON="/usr/local/bin/bots-webserver.py"
DAEMON_ARGS="-cconfig"
case "$1" in
start)
echo "Starting "$NAME" "
start-stop-daemon --start --verbose --background --pidfile $PIDFILE --make-pidfile --startas $DAEMON -- $DAEMON_ARGS
;;
stop)
echo "Stopping "$NAME" "
start-stop-daemon --stop --verbose --pidfile $PIDFILE
rm -f $PIDFILE
;;
restart)
echo "Restarting "$NAME" "
start-stop-daemon --stop --verbose --pidfile $PIDFILE
rm -f $PIDFILE
sleep 1
start-stop-daemon --start --verbose --background --pidfile $PIDFILE --make-pidfile --startas $DAEMON -- $DAEMON_ARGS
;;
*)
echo "Usage: ""$(basename "$0")"" {start|stop|restart}"
echo " Starts the bots webserver as a daemon."
echo " Bots-webserver is part of bots open source edi translator (http://bots.sourceforge.net)."
exit 1
;;
esac
exit 0
Example3
A script for starting the job queue server as a upstart in Ubuntu. Add the following file: /etc/init/bots-jobqueue.conf
description "Bots Job queue server"
author "bots@yourmail.com"
start on runlevel [2345]
stop on runlevel [!2345]
respawn
exec bots-jobqueueserver.py