I run CentOS for my production servers, and generally like to manage my services via proper init scripts. Over the years I’ve run into situations where I couldn’t locate a decent init script for a service I want to deploy, and end up rolling my own. I’m no shell scripting wizard, but they work well for me; it seems like something worth sharing so others don’t have to reinvent the wheel.
Today, I went hunting for an init script that I could use to manage a NodeJS application, and while I found a Debian-based one, no Redhat-style one was forthcoming. I tweaked the Debian one I found to work on a Redhat-style system. The script below should work fine for any Redhat/Redhat clone server. You’ll need to take care of a few things after you get the script:
Install the forever package so it’s in your PATH, which is easily accomplished via npm install -g forever if you have NPM installed.
Edit the variables in the APPLICATION section to suit your needs.
Put the script into /etc/init.d and name it something meaningful, I go with node-[appname].
Make sure the it’s executable.
If you want to have it automagically start/stop on startup/shutdown, activate it with chkconfig, like chkconfig --add [scriptname].
Manage it manually via the service app, eg. service [scriptname] start.
This script should be reusable to run more than one node app, provided that:
There’s one uniquely named script per node app.
The node apps are started on different ports.
#!/bin/sh
##
## Redhat / Linux / LSB
##
# chkconfig: 345 85 15
# description: Startup script for Express / Node.js application with the \
## forever module.
##
## A modification of https://gist.github.com/1339289
##
## This is free software; you may redistribute it and/or modify
## it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2,
## or (at your option) any later version.
##
## This is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
# Source function library.
. /etc/init.d/functions
################################################################################
################################################################################
## ##
# APPLICATION section #
## Edit the variables below for your installation ##
################################################################################
################################################################################
DESC="admin"
NAME="app.js"
DIR="/var/www"
APP=${DIR}/${DESC}/${NAME}
LOCKFILE=`basename $0 .sh`
export NODE_ENV=${NODE_ENV:="production"}
################################################################################
################################################################################
## ##
# PATHs section #
## ##
################################################################################
################################################################################
export PATH=$HOME/local/bin:${PATH:=}
export MANPATH=$HOME/local/man:${MANPATH:=}
export LD_LIBRARY_PATH=$HOME/local/lib:${LD_LIBRARY_PATH:=}
################################################################################
################################################################################
## ##
# FOREVER section #
## ##
################################################################################
################################################################################
running() {
forever list 2>/dev/null | grep ${APP} 2>&1 >/dev/null
return $?
}
start_server() {
forever start ${APP} 2>&1 >/dev/null
return $?
}
stop_server() {
forever stop ${APP} 2>&1 >/dev/null
return $?
}
################################################################################
################################################################################
## ##
# GENERIC section #
## ##
################################################################################
################################################################################
DIETIME=10 # Time to wait for the server to die, in seconds
# If this value is set too low you might not
# let some servers to die gracefully and
# 'restart' will not work
STARTTIME=2 # Time to wait for the server to start, in seconds
# If this value is set each time the server is
# started (on start or restart) the script will
# stall to try to determine if it is running
# If it is not set and the server takes time
# to setup a pid file the log message might
# be a false positive (says it did not start
# when it actually did)
# Console logging.
log() {
local STRING mode
STRING=$1
arg2=$2
mode="${arg2:=success}"
echo -n "$STRING "
if [ "${RHGB_STARTED:-}" != "" -a -w /etc/rhgb/temp/rhgb-console ]; then
echo -n "$STRING " > /etc/rhgb/temp/rhgb-console
fi
if [ "$mode" = "success" ]; then
success $"$STRING"
else
failure $"$STRING"
fi
echo
if [ "${RHGB_STARTED:-}" != "" -a -w /etc/rhgb/temp/rhgb-console ]; then
if [ "$mode" = "success" ]; then
echo_success > /etc/rhgb/temp/rhgb-console
else
echo_failure > /etc/rhgb/temp/rhgb-console
[ -x /usr/bin/rhgb-client ] && /usr/bin/rhgb-client --details=yes
fi
echo > /etc/rhgb/temp/rhgb-console
fi
}
# Starts the server.
do_start() {
# Check if it's running first
if running ; then
log "$DESC $NAME already running"
exit 0
fi
action "Starting $DESC $NAME" start_server
RETVAL=$?
if [ $RETVAL -eq 0 ]; then
# NOTE: Some servers might die some time after they start,
# this code will detect this issue if STARTTIME is set
# to a reasonable value
[ -n "$STARTTIME" ] && sleep $STARTTIME # Wait some time
if running ; then
# It's ok, the server started and is running
log "$DESC $NAME started"
touch /var/lock/subsys/$LOCKFILE
RETVAL=0
else
# It is not running after we did start
log "$DESC $NAME died on startup" "failure"
RETVAL=1
fi
fi
return $RETVAL
}
# Stops the server.
do_stop() {
if running ; then
# Only stop the server if we see it running
action "Stopping $DESC $NAME" stop_server
RETVAL=$?
[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$LOCKFILE
else
# If it's not running don't do anything
log "$DESC $NAME not running"
RETVAL=0
fi
return $RETVAL
}
case "$1" in
start)
do_start
RETVAL=$?
;;
stop)
do_stop
RETVAL=$?
;;
restart)
do_stop
RETVAL=$?
if [ $RETVAL -eq 0 ]; then
# Wait some sensible amount, some server need this
[ -n "$DIETIME" ] && sleep $DIETIME
do_start
RETVAL=$?
fi
;;
status)
if running ; then
log "$DESC $NAME running"
else
log "$DESC $NAME not running"
fi
RETVAL=0
;;
*)
echo "Usage: ${0} {start|stop|status|restart}"
RETVAL=1
;;
esac
exit $RETVAL