SystemV service startup script for a Ruby On Rails app with unicorn

gistfile1.sh

#!/bin/bash
#
# app                   Rails application served through an Unicorn instance
#
# Author                Romain Champourlier @ softr.li
#
# chkconfig: - 87 13
#
# description:          This a web application developed in Ruby On Rails
#                       which is served through an Unicorn instance.
# processname: unicorn_rails
# config: /path/to/your/app/config/unicorn.rb
# pidfile: /path/to/your/app/tmp/pids/unicorn.pid
#

### BEGIN INIT INFO
# Provides: app
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: unicorn running app
# Description: Unicorn instance running the a web app.
### END INIT INFO


# source function library
. /etc/rc.d/init.d/functions

APP_NAME="your_app_name"
APP="/path/to/your/$APP_NAME"
RVM_GEMSET="ruby-1.9.2-p290@gemset"

PIDFILE="$APP/tmp/pids/unicorn.pid"
LOCKFILE=/var/lock/subsys/$APP_NAME
RETVAL=0

USER=www
ENVIRONMENT=production

CD="cd $APP/"
RVM_USE="rvm use $RVM_GEMSET &>/dev/null"
SERVER_START="unicorn_rails -c config/unicorn.rb -E $ENVIRONMENT -D"

CMD="$CD; $RVM_USE; $SERVER_START"

start() {
    echo -n $"Starting Unicorn for '$APP_NAME': "

    # Looking at the pidfile to look if the server is already running.
    should_start=1
    if [ -f $PIDFILE ]; then
	checkpid `cat $PIDFILE`
	running=$?
	if [ $running -eq 0 ]; then
            # There is a pidfile and a process for that pid. We assume the
            # server is running and we pass.
	    echo_passed
	else
            # There is a pidfile but no process for that pid. We remove the
            # pidfile and set the server to be started.
	    rm -f $PIDFILE
	    should_start=0
	fi
    else
        # No pidfile. Should start.
	should_start=0
    fi

    if [ $should_start -eq 0 ]; then
	su - $USER -c "$CMD"
	if [ -f $PIDFILE ]; then
            # If there is a pidfile now, assuming success.
	    echo_success
	    RETVAL=0
	else
            # If there is no pidfile, assuming failure.
	    echo_failure
	    RETVAL=1
	fi
    fi
    echo
    [ $RETVAL -eq 0 ] && touch $LOCKFILE
    return $RETVAL
}

stop () {
    echo -n $"Stopping Unicorn for '$APP_NAME': "
    killproc -p $PIDFILE
    RETVAL=$?
    echo
    [ $RETVAL -eq 0 ] && rm -f $LOCKFILE $PIDFILE
}

case "$1" in
  start)
          start
          ;;
  stop)
          stop
          ;;
  restart)
          stop
          start
          ;;
  status)
        if [ -f $PIDFILE ]; then
            checkpid `cat $PIDFILE`
            running=$?
            if [ $running -eq 0 ]; then
		echo $"$APP_NAME is running..."
            else
                echo $"$APP_NAME is stopped"
            fi
        fi
        ;;
  *)
          echo $"Usage: $0 {start|stop|restart}"
          RETVAL=2
esac
exit $RETVAL

Improved the script to detect service state when starting/stopping according to the pidfile. Now displaying correctly OK or FAILURE according to the results of the request. Better structure too.

The script will start the unicorn server with a given user, and in a given RVM gemset.

Added a basic status implementation