Tutorials/Server startup script/Script

#!/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='minecraft'
 WORLD='world'
 MCPATH='/home/minecraft'
 BACKUPPATH='/minecraft/minecraft.backup'
 MAXHEAP=2048
 MINHEAP=1024
 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://piston-meta.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_%Hh%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_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
 }
 mc_listen() {
 if pgrep -u $USERNAME -f $SERVICE > /dev/null ; then
 as_user "tail -f $MCPATH/logs/latest.log"
 else
 echo "$SERVICE is not running. Cannot listen to server."
 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
 ;;
 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
 ;;
 listen)
 mc_listen
 ;;
 
 *)
 echo "Usage: $0 {start|stop|update|backup|status|restart|command \"server command\"}"
 exit 1
 ;;
 esac
 
 exit 0