A but.sh template to generate a SysV init script for running a .jar as a daemon

README.md

sysvinit-jar buttemplate

This is a but.sh template for creating /etc/rc.d/init.d scripts for Java jar files. (Slightly based on the EPEL init-script template, and intended for an el6 machine, though I'm sure it would work with many, many more systems.)

Other daemons?

After making this template, of course I realized that this could very easily be modified to do any other daemon, so I did just that, though it was honestly pretty trivial.

Prerequisites

This, of course, requires but.sh.

The template itself requires only bash and gnu-coreutils (for head and potentially echo).

Variables

Required:

• NAME -- The intended name of the daemon
• JAVA_BIN -- The path to the Java binary
• JAR -- The path to the jar to run

Optional:

(Unless otherwise specified for the variable, assume the default is null.)

• SUMMARY -- A very short summary of the daemon -- Defaults to the value of $NAME
• CHKCONFIG_START_LEVELS -- A string of runlevels (ex: '2345')
• CHKCONFIG_START_PRIORITY -- The starting priority, from 0-100 (0: started first) -- Defaults to 100
• CHKCONFIG_STOP_PRIORITY -- The stopping priority, from 0-100 (0: stopped first) -- Defaults to 0
• DESCRIPTION -- A longer description of the daemon, with lines separated by \n (see the manpage for echo for more backslash-sequences)
• LSB_PROVIDES -- The name(s) of the facilities that this daemon provides -- Defaults to the value of $NAME
• LSB_REQUIRED_START -- The name(s) of the facilities that this daemon needs to have running to be able to start
• LSB_REQUIRED_STOP -- The name(s) of the facilities that this daemon needs to have STILL running to be able to stop
• LSB_SHOULD_START -- The name(s) of the facilities that this daemon should start after; weak requires, but without failing if they don't exist
• LSB_SHOULD_STOP -- The name(s) of the facilities that this daemon should stop before; weak requires, but without failing if they don't exist
• LSB_DEFAULT_START -- A space-separated list of runlevels that this daemon should start on -- Defaults to space-separated $CHKCONFIG_START_LEVELS if that variable is set, otherwise null
• LSB_DEFAULT_STOP -- A space-separated list of runlevels that this daemon should not be running on -- Defaults to all in the range 0-6 that $LSB_DEFAULT_START does not include if $LSB_DEFAULT_START or $CHKCONFIG_START_LEVELS are set, otherwise null
• OUTLOG -- The log output file -- Defaults to /var/log/$NAME/$NAME.out
• ERRLOG -- The error logging file -- Defaults to /var/log/$NAME/$NAME.err
• JAR_ARGS -- The list of arguments to pass to the Java process (for the jar)

Downloading

wget https://gist.github.com/nealian/b3e40c8a7326ebea389e5fb97b3eeea3/raw/sysvinit-jar.buttemplate && wget https://gist.github.com/nealian/b3e40c8a7326ebea389e5fb97b3eeea3/raw/sysvinit-jar.buttemplate.functions

Usage

but.sh sysvinit-jar.buttemplate -c sysvinit-jar.buttemplate.functions -c daemon.environment -o /etc/rc.d/init.d/daemon

example-jar.environment

NAME=example
JAR=/path/to/ex.jar
JAVA_BIN=/usr/bin/java
CHKCONFIG_START_LEVELS=2345
CHKCONFIG_START_PRIORITY=80
CHKCONFIG_STOP_PRIORITY=20
DESCRIPTION="Hey look, this is\n
a multiline description"
JAR_ARGS='-arg1 val1 -arg2'

sysvinit-jar.buttemplate

#!/bin/sh
#
# ${NAME} ${SUMMARY=${NAME}}
#
# chkconfig:   ${CHKCONFIG_START_LEVELS--} ${CHKCONFIG_START_PRIORITY-100} ${CHKCONFIG_STOP_PRIORITY-0}
# description: $(echo -e ${DESCRIPTION} | while read line; do echo '# ' $line '\'; done | head -c -2 | tail -c +4)

### BEGIN INIT INFO
# Provides: ${LSB_PROVIDES-${NAME}}${LSB_REQUIRED_START+"$(echo)# Required-Start: ${LSB_REQUIRED_START}"}${LSB_REQUIRED_STOP+"$(echo)# Required-Stop: ${LSB_REQUIRED_STOP}"}${LSB_SHOULD_START+"$(echo)# Should-Start: ${LSB_SHOULD_START}"}${LSB_SHOULD_STOP+"$(echo)# Should-Stop: ${LSB_SHOULD_STOP}"}$(if [[ -n "$LSB_DEFAULT_START" ]]; then echo; echo "# Default-Start: ${LSB_DEFAULT_START}"; echo "# Default-Stop: ${LSB_DEFAULT_STOP-$(lsb_determine_stop_levels)}"; elif [[ -n "$CHKCONFIG_START_LEVELS" ]]; then echo; echo "# Default-Start: $(lsb_determine_start_levels)"; echo "# Default-Stop: ${LSB_DEFAULT_STOP-$(lsb_determine_stop_levels)}"; fi)
# Short-Description: ${SUMMARY}
# Description: $(echo -e ${DESCRIPTION} | while read line; do echo '# ' $line; done | head -c -1 | tail -c +4)
### END INIT INFO

# Source function library
. /etc/init.d/functions

exec='${JAVA_BIN}'
prog='${NAME}'
outlog='${OUTLOG-/var/log/${NAME}/${NAME}.out}'
errlog='${ERRLOG-/var/log/${NAME}/${NAME}.err}'

[ -e /etc/default/\$prog ] && . /etc/default/\$prog
$([[ -n "${JAR_ARGS}" ]] && (echo; echo args+=${JAR_ARGS}; echo))
pidfile=\"/var/run/\${prog}.pid\"

pstree() {
    local children=\$(pgrep -P \$1)
    for x in \$children; do
        echo \$x
        pstree \$x
    done
}

start() {
    local res pid
    [ -x \$exec ] || exit 5
    echo -n \"Starting \$prog:\"
    mkdir -p \$(dirname \$outlog) \$(dirname \$errlog)
    daemon --pidfile \$pidfile \$exec -jar ${JAR} \$args >>\$outlog 2>>\$errlog &
    res=\$?
    pid=\$!
    sleep 5
    (echo \$pid; pstree \$pid) > \$pidfile
    if [ \$res -eq 0 ]; then
        echo_success
    else
        echo_failure
    fi
    echo
}

stop() {
    local res
    echo -n \"Stopping \$prog:\"
    killproc -p \$pidfile \$prog
    res=\$?
    if [ \$res -eq 0 ]; then
        echo_success
    else
        echo_failure
    fi
    echo
}

restart() {
    stop
    start
}

reload() {
    restart
}

force_reload() {
    restart
}

rh_status() {
    status -p \$pidfile \$prog
}

rh_status_q() {
    rh_status >/dev/null 2>&1
}


case \"\$1\" in
    start)
        rh_status_q && exit 0
        \$1
        ;;
    stop)
        rh_status_q || exit 0
        \$1
        ;;
    restart)
        \$1
        ;;
    reload)
        rh_status_q || exit 7
        \$1
        ;;
    force-reload)
        force_reload
        ;;
    status)
        rh_status
        ;;
    condrestart|try-restart)
        rh_status_q || exit 0
        restart
        ;;
    *)
        echo \"Usage: \$0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload}\"
        exit 2
esac
exit \$?

sysvinit-jar.buttemplate.functions

function lsb_determine_start_levels() {
  _split_chars ${CHKCONFIG_START_LEVELS} ' '
}

function lsb_determine_stop_levels() {
  _split_chars $(_exclude ${LSB_DEFAULT_START:-${CHKCONFIG_START_LEVELS}} '0123456') ' '
}

function _exclude() {
  local a=$2
  for (( i=0; i<${#1}; i++ )); do
    a=${a//${1:$i:1}/}
  done
  echo $a
}

function _split_chars() {
  for (( i=0; i<${#1}; i++ )); do
    echo -n "${1:$i:1}${2}"
  done | head -c -${#2}
}