Daemon init script for node.js based app/server (DEBIAN/UBUNTU)

node_debian_init.sh

#!/bin/sh
# ------------------------------------------------------------------------------ 
# SOME INFOS : fairly standard (debian) init script.
#                 Note that node doesn't create a PID file (hence --make-pidfile) 
#                 has to be run in the background (hence --background)
#                 and NOT as root (hence --chuid)
#
# MORE INFOS :  INIT SCRIPT       http://www.debian.org/doc/debian-policy/ch-opersys.html#s-sysvinit
#               INIT-INFO RULES   http://wiki.debian.org/LSBInitScripts
#               INSTALL/REMOVE    http://www.debian-administration.org/articles/28
# ------------------------------------------------------------------------------
#                                                                              #
#                     BEGIN <MODIFY TO REFLECT YOUR SETTINGS>                  #
#                                                                              #
#
#  1) Don't forget to also modify the COMMENTED fields in the "### BEGIN INIT INFO"
#     below (don't uncomment them) if you wish to install system-wide with update-rc.d
#     eg: provides, Short-Description, Description
#
#  2) in case you have different node.js servers running, each init.d script should
#     (obviously) have a UNIQUE BASE name so that PIDS do not conflict
#     --> name them accordingly
#     eg: node_static_server, node_express1, node_load_balancer.sh...
#
#  3) copy the renamed/modified script(s) to /etc/init.d
#     chmod 755,
#
#  4) if you wish the Daemon to be lauched at boot / stopped at shutdown :
#     INSTALL : update-rc.d scriptname defaults 
#     (UNINSTALL : update-rc.d -f  scriptname remove)
#
#  5)  based on : Debian /etc/init.d/skeleton
#      modified by : Peter Host (www.oghme.com)
# ______________________________________________________________________________ 
### BEGIN INIT INFO
# Provides:          node_debian_init
# Required-Start:    $remote_fs $named $syslog
# Required-Stop:     $remote_fs $named $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: DEBIAN initscript for node.js servers/apps
# Description:       ex : proxy server is a node.js http server listening on
#                    port 8080 (relayed from 80 by iptables). It balances
#                    http requests between the main nodejs server 
#                    (nodejs.mydomain.com:8000), the static file-server 
#                    (static.mydomain.com) and the legacy apache server
#                    (apache.mydomain.com) and possibly other servers
#                    place this file in /etc/init.d.
### END INIT INFO

# Author: My Name <[email protected]>
#
# Please remove the "Author" lines above and replace them
# with your own name if you copy and modify this script.
# ______________________________________________________________________________ 
#
# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/bin # modify if you need

DAEMON_ARGS="/path/to/app.js"               # path to your node.js server/app
                                            # NB: don't use ~/ in path

DESC="node.js http server"                  # whatever fancy description you like

NODEUSER=myuser:mygroup                     # USER who OWNS the daemon process (no matter whoever runs the init script)
                                            # user:group (if no group is specified, the primary GID for that user is used)

LOCAL_VAR_RUN=/usr/local/var/run            # in case the init script is run by non-root user, you need to
                                            # indicate a directory writeable by $NODEUSER to store the PID file
                                            # NB : 1) /usr/local/var/run does not exist by DEFAULT. Either create it
                                            #      or choose one of your own liking.
                                            #      2) node, npm,... are best NOT installed/run as ROOT.
                                            #         (see here: https://github.com/isaacs/npm/blob/master/README.md)

NAME=node                                   # name of the node.js executable
DAEMON=/usr/local/bin/$NAME                 # this SHOULD POINT TO where your node executable is
#
#                                                                              #
#                   END </MODIFY TO REFLECT YOUR SETTINGS>                     #
#                (Nothing else to modify from this point on...)                #
# ------------------------------------------------------------------------------ 





# Do NOT "set -e"

[ $UID -eq "0" ] && LOCAL_VAR_RUN=/var/run # in case this script is run by root, override user setting
THIS_ARG=$0
INIT_SCRIPT_NAME=`basename $THIS_ARG`
[ -h $THIS_ARG ] && INIT_SCRIPT_NAME=`basename $(readlink $THIS_ARG)` # in case of symlink
INIT_SCRIPT_NAME_NOEXT=${INIT_SCRIPT_NAME%.*}                            
PIDFILE="$LOCAL_VAR_RUN/$INIT_SCRIPT_NAME_NOEXT.pid"
SCRIPTNAME=/etc/init.d/$INIT_SCRIPT_NAME

# Exit if the package is not installed
[ -x "$DAEMON" ] ||  { echo "can't find Node.js ($DAEMON)"  >&2; exit 0; }

# Exit if the 'run' folder is not present
[ -d "$LOCAL_VAR_RUN" ] || { echo "Directory $LOCAL_VAR_RUN does not exist. Modify the '$INIT_SCRIPT_NAME_NOEXT' init.d script ($THIS_ARG) accordingly" >&2; exit 0; }

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

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

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

# uncomment to override system setting
# VERBOSE=yes

#
# 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
	start-stop-daemon --start --quiet --pidfile $PIDFILE --chuid $NODEUSER --background --exec $DAEMON --test > /dev/null \
		|| { [ "$VERBOSE" != no ] && log_daemon_msg  "  --->  Daemon already running $DESC" "$INIT_SCRIPT_NAME_NOEXT"; return 1; }
	start-stop-daemon --start --quiet --chuid $NODEUSER --make-pidfile --pidfile $PIDFILE --background --exec $DAEMON -- \
		$DAEMON_ARGS \
		|| { [ "$VERBOSE" != no ] && log_daemon_msg  "  --->  could not be start $DESC" "$INIT_SCRIPT_NAME_NOEXT"; return 2; }
	# Add code here, if necessary, that waits for the process to be ready
	# to handle requests from services started subsequently which depend
	# on this one.  As a last resort, sleep for some time.
	[ "$VERBOSE" != no ] && log_daemon_msg  "  --->  started $DESC" "$INIT_SCRIPT_NAME_NOEXT"
}

#
# Function that stops the daemon/service
#
do_stop()
{
	# 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  --chuid $NODEUSER --name $DAEMON
	RETVAL="$?"
	#[ "$VERBOSE" != no ] && [ "$RETVAL" = 1 ] && log_daemon_msg  "  --->  SIGKILL failed => hardkill $DESC" "$INIT_SCRIPT_NAME_NOEXT"
	[ "$RETVAL" = 2 ] && return 2
	# Wait for children to finish too if this is a daemon that forks
	# and if the daemon is only ever run from this initscript.
	# If the above conditions are not satisfied then add some other code
	# that waits for the process to drop all resources that could be
	# needed by services started subsequently.  A last resort is to
	# sleep for some time.
	start-stop-daemon --stop --quiet --oknodo --retry=0/3/KILL/5 --pidfile $PIDFILE  --chuid $NODEUSER --exec $DAEMON -- $DAEMON_ARGS
	[ "$?" = 2 ] && return 2
	# Many daemons don't delete their pidfiles when they exit.
	rm -f $PIDFILE
  [ "$VERBOSE" != no ] && [ "$RETVAL" = 1 ] && log_daemon_msg "  --->  $DESC not running" "$INIT_SCRIPT_NAME_NOEXT"
  [ "$VERBOSE" != no -a "$RETVAL" = 0 ] && log_daemon_msg "  --->  $DESC stopped" "$INIT_SCRIPT_NAME_NOEXT"
	return "$RETVAL"
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
	#
	# If the daemon can reload its configuration without
	# restarting (for example, when it is sent a SIGHUP),
	# then implement that here.
	#
	start-stop-daemon --stop --quiet --signal 1 --pidfile $PIDFILE  --chuid $NODEUSER --name $NAME
	return 0
}

#
# Function that returns the daemon 
#
do_status() {
  #
  # http://refspecs.freestandards.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html
  # 0 program is running or service is OK
  # 1 program is dead and /var/run pid file exists
  # (2 program is dead and /var/lock lock file exists) (not used here)
  # 3 program is not running
  # 4 program or service status is unknown
  RUNNING=$(running)
  
  # $PIDFILE corresponds to a live $NAME process
  ispidactive=$(pidof $NAME | grep `cat $PIDFILE 2>&1` >/dev/null 2>&1)
  ISPIDACTIVE=$?

  if [ -n "$RUNNING" ]; then
    if [ $ISPIDACTIVE ]; then 
      log_success_msg "$INIT_SCRIPT_NAME_NOEXT (launched by $USER) (--chuid $NODEUSER) is running"
      exit 0      
    fi
  else
    if [ -f $PIDFILE ]; then
      log_success_msg "$INIT_SCRIPT_NAME_NOEXT (launched by $USER) (--chuid $NODEUSER) is not running, phantom pidfile $PIDFILE"
      exit 1
    else
      log_success_msg "no instance launched by $USER, of $INIT_SCRIPT_NAME_NOEXT (--chuid $NODEUSER) found"
      exit 3
    fi
  fi
  
}

running() {
  RUNSTAT=$(start-stop-daemon --start --quiet --pidfile $PIDFILE --chuid $NODEUSER --background --exec $DAEMON --test > /dev/null)
  if [ "$?" = 1 ]; then
    echo y
  fi
  
}


case "$1" in
  start)
	[ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$INIT_SCRIPT_NAME_NOEXT"
	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 $DESC" "$INIT_SCRIPT_NAME_NOEXT"
	do_stop
	case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	esac
	;;
  #reload|force-reload)
	#
	# If do_reload() is not implemented then leave this commented out
	# and leave 'force-reload' as an alias for 'restart'.
	#
	#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 $DESC" "$INIT_SCRIPT_NAME_NOEXT"
	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
	;;
  status)
    do_status
  ;;
  *)
	#echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2
	echo "Usage: $SCRIPTNAME {start|stop|restart|force-reload}" >&2
	exit 3
	;;
esac

exit 0