Simple Minecraft server management script

minecraft.sh

#!/bin/bash
# /etc/init.d/minecraft
# version 0.4.2 2016-02-09 (YYYY-MM-DD)
#
### BEGIN INIT INFO
# Provides:   minecraft
# Required-Start: $local_fs $remote_fs screen-cleanup
# Required-Stop:  $local_fs $remote_fs
# Should-Start:   $network
# Should-Stop:    $network
# Default-Start:  2 3 4 5
# Default-Stop:   0 1 6
# Short-Description:    Minecraft server
# Description:    Starts the minecraft server
### END INIT INFO

#Settings
SERVICE='minecraft_server.jar'
SCREENNAME='minecraft_server'
OPTIONS='nogui'
USERNAME='adam'
WORLD='world'
MCPATH='/home/adam/mc'
BACKUPPATH='/home/adam/mc.backups'
MAXHEAP=768
MINHEAP=512
HISTORY=1024
CPU_COUNT=1
INVOCATION="java -Xmx${MAXHEAP}M -Xms${MINHEAP}M -XX:+UseConcMarkSweepGC \
-XX:+CMSIncrementalPacing -XX:ParallelGCThreads=$CPU_COUNT -XX:+AggressiveOpts \
-jar $SERVICE $OPTIONS"

ME=`whoami`
as_user() {
if [ "$ME" = "$USERNAME" ] ; then
bash -c "$1"
else
su - "$USERNAME" -c "$1"
fi
}

mc_start() {
if  pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "$SERVICE is already running!"
else
echo "Starting $SERVICE..."
cd $MCPATH
as_user "cd $MCPATH && screen -h $HISTORY -dmS ${SCREENNAME} $INVOCATION"
sleep 7
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "$SERVICE is now running."
else
echo "Error! Could not start $SERVICE!"
fi
fi
}

mc_saveoff() {
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "$SERVICE is running... suspending saves"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"say SERVER BACKUP STARTING. Server going readonly...\"\015'"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"save-off\"\015'"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"save-all\"\015'"
sync
sleep 10
else
echo "$SERVICE is not running. Not suspending saves."
fi
}

mc_saveon() {
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "$SERVICE is running... re-enabling saves"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"save-on\"\015'"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"say SERVER BACKUP ENDED. Server going read-write...\"\015'"
else
echo "$SERVICE is not running. Not resuming saves."
fi
}

mc_stop() {
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "Stopping $SERVICE"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"say SERVER SHUTTING DOWN IN 10 SECONDS. Saving map...\"\015'"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"save-all\"\015'"
sleep 10
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"stop\"\015'"
sleep 7
else
echo "$SERVICE was not running."
fi
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "Error! $SERVICE could not be stopped."
else
echo "$SERVICE is stopped."
fi
}

mc_update() {
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "$SERVICE is running! Will not start update."
else
as_user "cd $MCPATH && wget -q -O $MCPATH/versions --no-check-certificate https://launchermeta.mojang.com/mc/game/version_manifest.json"
if [ "$1" == "snapshot" ] ; then
JSONVERSION=`cd $MCPATH && cat versions | python -c "exec(\"import json,sys\nobj=json.load(sys.stdin)\nversion=obj['latest']['snapshot']\nfor v in obj['versions']:\n   if v['id']==version:\n    print(v['url'])\")"`
else
JSONVERSION=`cd $MCPATH && cat versions | python -c "exec(\"import json,sys\nobj=json.load(sys.stdin)\nversion=obj['latest']['release']\nfor v in obj['versions']:\n   if v['id']==version:\n    print(v['url'])\")"`
fi
as_user "cd $MCPATH && wget -q -O $MCPATH/versions --no-check-certificate $JSONVERSION"
MC_SERVER_URL=`cd $MCPATH && cat versions | python -c 'import json,sys;obj=json.load(sys.stdin);print(obj["downloads"]["server"]["url"])'`
as_user "rm $MCPATH/versions"
as_user "cd $MCPATH && wget -q -O $MCPATH/minecraft_server.jar.update --no-check-certificate $MC_SERVER_URL"
if [ -f $MCPATH/minecraft_server.jar.update ] ; then
if `diff $MCPATH/$SERVICE $MCPATH/minecraft_server.jar.update >/dev/null` ; then
echo "You are already running the latest version of $SERVICE."
else
as_user "mv $MCPATH/minecraft_server.jar.update $MCPATH/$SERVICE"
echo "Minecraft successfully updated."
fi
else
echo "Minecraft update could not be downloaded."
fi
fi
}

mc_backup() {
mc_saveoff

NOW=`date "+%Y-%m-%d_%H.%M"`
BACKUP_FILE="$BACKUPPATH/${WORLD}_${NOW}.tar"
echo "Backing up minecraft world..."
#as_user "cd $MCPATH && cp -r $WORLD $BACKUPPATH/${WORLD}_`date "+%Y.%m.%d_%H.%M"`"
as_user "tar -C \"$MCPATH\" -cf \"$BACKUP_FILE\" $WORLD"

echo "Backing up $SERVICE"
as_user "tar -C \"$MCPATH\" -rf \"$BACKUP_FILE\" $SERVICE"
#as_user "cp \"$MCPATH/$SERVICE\" \"$BACKUPPATH/minecraft_server_${NOW}.jar\""

mc_saveon

echo "Compressing backup..."
as_user "gzip -f \"$BACKUP_FILE\""
echo "Done."
}

mc_cleanup() {
cd $BACKUPPATH && ls -t | sed -e '1,8d' | xargs -d '\n' rm
}

mc_command() {
command="$1";
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
pre_log_len=`wc -l "$MCPATH/logs/latest.log" | awk '{print $1}'`
echo "$SERVICE is running... executing command"
as_user "screen -p 0 -S ${SCREENNAME} -X eval 'stuff \"$command\"\015'"
sleep .1 # assumes that the command will run and print to the log file in less than .1 seconds
# print output
tail -n $((`wc -l "$MCPATH/logs/latest.log" | awk '{print $1}'`-$pre_log_len)) "$MCPATH/logs/latest.log"
fi
}

#Start-Stop here
case "$1" in
start)
mc_start
;;
stop)
mc_stop
;;
restart)
mc_stop
mc_start
;;
update)
mc_stop
mc_backup
mc_update $2
mc_start
;;
backup)
mc_backup
;;
cleanup)
mc_cleanup
;;
status)
if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
echo "$SERVICE is running."
else
echo "$SERVICE is not running."
fi
;;
command)
if [ $# -gt 1 ] ; then
shift
mc_command "$*"
else
echo "Must specify server command (try 'help'?)"
fi
;;

*)
echo "Usage: $0 {start|stop|update|backup|status|restart|command \"server command\"}"
exit 1
;;
esac

exit 0