Linux script to manage minecraft server

minecraft

#!/bin/bash
### 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

# /etc/init.d/minecraft-amped
# version 0.4.0 2015-04-20 (YYYY-MM-DD)
#


## SETTINGS ##

# NOTE: change "Provides" above to unique value if running multiple minecraft servers

# path that has minecraft jar ($SERVICE), settings files, and world folder ($WORLD)
MCPATH='/path/to/minecraft'

# name of minecraft jar in $MCPATH
# if running multiple servers use a unique jar name
SERVICE='NAME-OF-MINECRAFT.jar'

# run in server mode
OPTIONS='nogui'

# run as 'minecraft' user
USERNAME='minecraft'

# name of folder containing world data in $MCPATH
WORLD='NAME-OF-WORLD-FOLDER'

# where to store world backups
BACKUPPATH='/path/to/backups'

# name to use for screen session server will run in
# if running multiple servers use a unique SCREEN_NAME
SCREEN_NAME='UNIQUE-SCREEN-NAME'
# screen history
HISTORY=1024

# JVM path and settings
JAVA_HOME="/path/to/jvm"
export JAVA_HOME="/path/to/jvm"
MAXHEAP=2056
MINHEAP=1024
CPU_COUNT=4
INVOCATION="java -Xmx${MAXHEAP}M -Xms${MINHEAP}M -XX:+UseConcMarkSweepGC \
-XX:+CMSIncrementalPacing -XX:ParallelGCThreads=$CPU_COUNT -XX:+AggressiveOpts \
-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=9011 \
-Dcom.sun.management.jmxremote.local.only=false -Dcom.sun.management.jmxremote.authenticate=false \
-jar $SERVICE $OPTIONS"

## END SETTINGS ##

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 $SCREEN_NAME $INVOCATION"
    sleep 7
    if pgrep -u $USERNAME -f $SERVICE > /dev/null
    then
      echo "$SERVICE is now running."
      as_user "cd $MCPATH && minecraft comment \"gamerule keepInventory true\""
    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 $SCREEN_NAME -X eval 'stuff \"say SERVER BACKUP STARTING. Server going readonly...\"\015'"
    as_user "screen -p 0 -S $SCREEN_NAME -X eval 'stuff \"save-off\"\015'"
    as_user "screen -p 0 -S $SCREEN_NAME -X eval 'stuff \"save-all\"\015'"
    sync
    sleep 10
  else
    echo "$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 $SCREEN_NAME -X eval 'stuff \"save-on\"\015'"
    as_user "screen -p 0 -S $SCREEN_NAME -X eval 'stuff \"say SERVER BACKUP ENDED. Server going read-write...\"\015'"
  else
    echo "$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 $SCREEN_NAME -X eval 'stuff \"say SERVER SHUTTING DOWN IN 10 SECONDS. Saving map...\"\015'"
    as_user "screen -p 0 -S $SCREEN_NAME -X eval 'stuff \"save-all\"\015'"
    sleep 10
    as_user "screen -p 0 -S $SCREEN_NAME -X eval 'stuff \"stop\"\015'"
    sleep 7
  else
    echo "$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 $MCPATH/versions http://s3.amazonaws.com/Minecraft.Download/versions/versions.json"
	snap=`awk -v linenum=3 'NR == linenum {print; exit}' "$MCPATH/versions"`
	snapVersion=`echo $snap | awk -F'\"' '{print $4}'`
	re=`awk -v linenum=4 'NR == linenum {print; exit}' "$MCPATH/versions"`
	reVersion=`echo $re | awk -F'\"' '{print $4}'`
	as_user "rm $MCPATH/versions"
	if [ "$1" == "snapshot" ]; then
	MC_SERVER_URL=http://s3.amazonaws.com/Minecraft.Download/versions/$snapVersion/minecraft_server.$snapVersion.jar
	else
	MC_SERVER_URL=http://s3.amazonaws.com/Minecraft.Download/versions/$reVersion/minecraft_server.$reVersion.jar
	fi
    as_user "cd $MCPATH && wget -q -O $MCPATH/minecraft_server.jar.update $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 $SCREEN_NAME -X eval 'stuff \"$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
    ;;
  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