Ich habe einige Tage nach einer einfachen Möglichkeit gesucht, meine Java Programme als Daemon auf Debian Linux zu starten. Es gibt einiges an Scripten für SuSe und davon auch Portierungen auf Debian. Allerdings fand‘ ich diese Implementierungen immer unnötig kompliziert und unübersichtlich.
Gestern bin ich endlich auf eine einfache und klar programmierte Lösung gestossen. Ein einfacher Wrapperskript der alle benötigten Funktionen unterstützt. Der Skript ist von 2009 läuft aber noch einwandfrei. Allerdings ist er nicht auf Debian spezialisiert und ist für die KSH geschrieben. Ich bin mal alles durchgegangen und habe einige Anpassungen gemacht. Herausgekommen ist folgende Debian interpretation:
#! /bin/sh
### BEGIN INIT INFO
# Provides: skeleton
# Required-Start: $remote_fs $syslog $network
# Required-Stop: $remote_fs $syslog $network
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Java Daemon Script
# Description: This file should be used to construct scripts to be
# placed in /etc/init.d.
### END INIT INFO
# Author: Jens Heuschkel <jens@3und20.eu>
# Do NOT "set -e"
# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/sbin:/usr/sbin:/bin:/usr/bin
APP_NAME="MyApp"
APP_LONG_NAME="My App Server"
#the location of the pid files.
PIDDIR="/var/run"
PIDFILE="${PIDDIR}/${APP_NAME}.pid"
TIMESTAMP=$( date +%Y%m%d_%H%M%S )
#number of seconds to wait after starting up.
WAIT_AFTER_STARTUP=2
#the location of the log files
LOG_DIR="/var/log"
STDOUT="${LOG_DIR}/${APP_NAME}.stdout.log"
#PURGE_EXPRESSION="-mtime +2"
PURGE_EXPRESSION="${LOG_DIR}/${APP_NAME}*"
HEAPSIZE_INIT=16
HEAPSIZE_MAX=100
VMARGS="-Xms${HEAPSIZE_INIT}M -Xmx${HEAPSIZE_MAX}M -verbose:gc"
MAINCLASS="com.wordpress.jensheuschkel.MyApplication"
JARFILE="MyApp.jar"
ARGS=""
JAVA_COMMAND="/usr/bin/java"
# Startup with Classpath
#START_COMMAND="${JAVA_COMMAND} $VMARGS $MAINCLASS $ARGS"
# Startup with jar
START_COMMAND="${JAVA_COMMAND} $VMARGS -jar ${JARFILE} ${ARGS}"
#-----------------------------------------------------------------------------
# Do not modify anything beyond this point
#-----------------------------------------------------------------------------
checkroot() {
if [[ $EUID -ne 0 ]]; then
echo "This script must be run as root" 1>&2
exit 1
fi
}
getpid() {
pid=""
if [ -f "$PIDFILE" ]
then
if [ -r "$PIDFILE" ]
then
pid=`cat "$PIDFILE"|cut -d: -f1`
host=`cat "$PIDFILE"|cut -d: -f2`
currhost=`hostname`
if [ "$host" != "$currhost" ]
then
echo "You are on the wrong host. $APP_LONG_NAME runs on $host."
exit 1
fi
if [ "X$pid" != "X" ]
then
kill -0 $pid > /dev/null 2>&1
if [ $? -ne 0 ]
then
# Process doesn't exist, so remove pidfile
rm -f "$PIDFILE"
echo "Removed stale pid file: $PIDFILE"
pid=""
fi
fi
else
echo "Cannot read $PIDFILE."
exit 1
fi
fi
}
#tests if the pid is alive
testpid() {
kill -0 $pid > /dev/null 2>&1
if [ $? -ne 0 ]
then
# Process is gone so remove the pid file.
rm -f "$PIDFILE"
pid=""
fi
}
start() {
echo "Starting $APP_LONG_NAME..."
getpid
if [ "X$pid" = "X" ]
then
if [ -s $STDOUT ]
then
#backup current file
mv $STDOUT $STDOUT.sav.${TIMESTAMP}
fi
echo CLASSPATH is $CLASSPATH > $STDOUT
echo ${START_COMMAND} >> $STDOUT
nohup ${START_COMMAND} >> $STDOUT 2>&1 &
echo $!:`hostname` > $PIDFILE
else
echo "$APP_LONG_NAME is already running."
exit 1
fi
# Sleep for a few seconds to allow for intialization if required
# then test to make sure we're still running.
i=0
while [ $i -lt $WAIT_AFTER_STARTUP ]
do
sleep 1
i=`expr $i + 1`
done
if [ $WAIT_AFTER_STARTUP -gt 0 ]
then
getpid
if [ "X$pid" = "X" ]
then
echo "WARNING: $APP_LONG_NAME may have failed to start."
exit 1
else
echo "running ($pid)."
fi
else
echo ""
fi
}
stopit() {
echo "Stopping $APP_LONG_NAME..."
getpid
if [ "X$pid" = "X" ]
then
echo "$APP_LONG_NAME was not running."
else
# Running so try to stop it.
kill $pid
if [ $? -ne 0 ]
then
echo "Unable to stop $APP_LONG_NAME."
exit 1
fi
# If it has not stopped in 10 tries, forcibly kill it
savepid=$pid
CNT=0
TOTCNT=0
while [ "X$pid" != "X" ]
do
# Show a waiting message every 5 seconds.
if [ "$CNT" -lt "5" ]
then
CNT=`expr $CNT + 1`
else
echo "Waiting for $APP_LONG_NAME to exit..."
CNT=0
fi
if [ $TOTCNT -gt 11 ]
then
echo "Killing by force (kill -9)"
kill -9 $pid
fi
TOTCNT=`expr $TOTCNT + 1`
sleep 1
testpid
done
pid=$savepid
testpid
if [ "X$pid" != "X" ]
then
echo "Failed to stop $APP_LONG_NAME."
exit 1
else
echo "Stopped $APP_LONG_NAME."
fi
fi
}
purge() {
# pcmd="find $LOG_DIR -follow -type f $PURGE_EXPRESSION -print -exec rm -f {} +"
pcmd="rm -f ${PURGE_EXPRESSION}"
echo "Running purge: $pcmd"
$pcmd
}
alert() {
if [ "X$EMAIL" != "X" ]
then
echo "$APP_LONG_NAME is not running on `hostname`. Please check and restart." \
| mailx -s "`hostname`: $APP_LONG_NAME is not running" "$EMAIL"
echo "Sent alert to $EMAIL"
fi
}
status() {
getpid
if [ "X$pid" = "X" ]
then
echo "$APP_LONG_NAME is not running."
alert
exit 1
else
echo "$APP_LONG_NAME is running (PID:$pid)."
exit 0
fi
}
dump() {
echo "Dumping $APP_LONG_NAME..."
getpid
if [ "X$pid" = "X" ]
then
echo "$APP_LONG_NAME is not running."
else
kill -3 $pid
if [ $? -ne 0 ]
then
echo "Failed to dump $APP_LONG_NAME."
exit 1
else
echo "Dumped $APP_LONG_NAME."
fi
fi
}
####################
checkroot
case "$1" in
'start')
start
;;
'stop')
stopit
;;
'restart')
stopit
start
;;
'status')
status
;;
'dump')
dump
;;
'purge')
purge
;;
*)
echo "Usage: $0 { start | stop | restart | status | dump | purge }"
exit 1
;;
esac
exit 0
Die VM Einstellungen sind für das Rapberry Pi und sollten noch angepasst werden. Es wird auch nicht gecheckt ob JAVA installiert ist aber das kann man ja im Install-Skript des Servers machen 😉
Quelle:
http://fahdshariff.blogspot.de/2009/09/unix-wrapper-script-for-java.html
Trust me I'm an engineer! 