A bash script to generate huge Minecraft worlds in several smaller parts

gistfile1.sh

#!/bin/bash
#
# Author: masa
# Date: 2014-11-11
#
# A script for automatically creating (from a template), starting, stopping and running
# a command on multiple Minecraft server instances.
# The goal is to quickly generate a huge Minecraft world in a multiprocessor environment.
# The script is currently built around running 16 separate instances at once,
# and the world it will generate is 50k x 50k blocks (about, a little more since it is 100 x 100 region files).
# The script assumes the Admin Command Toolbox mod by ProfMobius has been installed (requires a Forge based server).
#
# To use this script, you want to configure the TEMPLATE_DIR to point to a server template, which the script will
# then duplicate to 16 different directories. If/when you want a consistent world (no biome borders/inconsistencies),
# then be sure to have a world/ dir with a level.dat for the seed in the template dir, OR have the seed set
# in the server.properties file.
#
# Also set the DST_DIR to point to the root directory under which the separate server instances will be created.
# The COMBINED_WORLD_DIR will have the final, combined set of region files after you run the move_regions command.
# WORLD_DIR is used when moving the regions files to the final directory, it should match the one set in
# server.properties, which is just 'world' by default.
# Be sure to have the server jar named as 'minecraft_server.jar' inside the template dir, or adjust the SERVICE variable.
# It must contain the name of the server jar, WITHOUT the '.jar' extension.
#
# Set the BASE_PORT to the port for the first instance. The script will automatically increase it by one
# for each server instance and write it to the instance's server.properties.
# Set the USERNAME to the username you want to run server processes as.
#
# The available commands are:
# create_all - Creates all the server instances by copying the template directory, and modifying the port in server.properties.
# start_all - Starts all the server instances in screen sessions named as 'mc_server_01' etc.
# stop_all - Stops all the running server instances.
# pregen_all - Runs the pregen command from Admin Command Toolbox mod by ProfMobius. Each server instance will generate a separate 12.5k x 12.5k region.
# move_regions - Moves the right region files from each server instance to the final location. You should only run this when the servers have been shut down.
#
# If you want to generate a different size world, or use a different number of processes, then a decent amount of
# changes are needed. The number of instances can be changed easily in the 'Process the commands' section on the bottom.
# You must however modify the pregen commands according to your desired world size, and also change the calculations
# in the mc_move_regions function accordingly.
#
# Some tips for those:
# The pregen command format is: /pregen <dimension> <startX> <endX> <startZ> <endZ>
# The coordinates for pregen are CHUNK coordinates.
# A chunk is 16x16 blocks. A region file is 512x512 blocks, which is 32x32 chunks.
# Do the math based on those ;)

TEMPLATE_DIR="/tmp/tmpl"
DST_DIR="/tmp/servers"
COMBINED_WORLD_DIR="/tmp/final_world"
WORLD_DIR="world"	# The name of the world directory
SERVICE="minecraft_server"	# Base name of the server jar (in templates, this would be minecraft_server.jar, in the instances it will become minecraft_server_12.jar etc.)
BASE_PORT="25565"

USERNAME="masa"
SCREEN_SESSION="mc_server"
INVOCATION="java -Xms2G -Xmx3G -XX:PermSize=256m -Xincgc -XX:+UseConcMarkSweepGC -jar"
OPTIONS="nogui"

export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8

as_user() {
	ME=`whoami`

	if [ ${ME} == ${USERNAME} ] ; then
		bash -c "${1}"
	else
		su - ${USERNAME} -c "${1}"
	fi
}


mc_create_instances() {

	PORT=${BASE_PORT}
	LAST="${1}"

	for i in `seq 1 ${LAST}`;
	do
		NUM=`printf %02d ${i}`
		cp -auxi "${TEMPLATE_DIR}" "${DST_DIR}/server_${NUM}"
		mv -i "${DST_DIR}/server_${NUM}/${SERVICE}.jar" "${DST_DIR}/server_${NUM}/${SERVICE}_${NUM}.jar"
		sed -i "s/server-port=.*/server-port=${PORT}/; s/query.port=.*/query.port=${PORT}/" "${DST_DIR}/server_${NUM}/server.properties"
		((PORT += 1))
	done
}


mc_start() {
	L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
	L_PREFIX="${L_TIMESTAMP}"

	NUM=`printf %02d ${i}`
	LOCAL_SERVICE="${SERVICE}_${NUM}.jar"
	LOCAL_INVOCATION="${INVOCATION} ${LOCAL_SERVICE} ${OPTIONS}"
	INSTANCE_PATH="${DST_DIR}/server_${NUM}"

	# Check that the server is not already running
	if pgrep -u ${USERNAME} -f ${LOCAL_SERVICE} > /dev/null
	then
		echo "${L_PREFIX} [WARNING] mc_start(): ${LOCAL_SERVICE} is already running"
	else
		echo "${L_PREFIX} [INFO] mc_start(): Starting ${LOCAL_SERVICE}..."

		# Start the server process
		as_user "cd ${INSTANCE_PATH} && screen -dmS ${SCREEN_SESSION}_${NUM} ${LOCAL_INVOCATION}"
		sleep 1

		# Verify that the server process was started successfully, by checking a few times in a delayed loop
		COUNTER=0
		while [ $COUNTER -lt 30 ]; do

			if pgrep -u ${USERNAME} -f ${LOCAL_SERVICE} > /dev/null
			then
				L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
				L_PREFIX="${L_TIMESTAMP}"

				echo "${L_PREFIX} [INFO] mc_start(): ${LOCAL_SERVICE} is now running"

				break
			fi

			sleep 1

			((COUNTER += 1))
		done

		# If the loop counter hit the max value, the process was not started successfully
		if [ ${COUNTER} -ge 30 ]
		then
			L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
			L_PREFIX="${L_TIMESTAMP}"

			echo "${L_PREFIX} [ERROR] mc_start(): Could not start ${LOCAL_SERVICE}"
		fi
	fi
}


mc_stop() {
	L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
	L_PREFIX="${L_TIMESTAMP}"

	NUM=`printf %02d ${i}`
	LOCAL_SERVICE="${SERVICE}_${NUM}.jar"

	# Check that the process is running
	if pgrep -u ${USERNAME} -f ${LOCAL_SERVICE} > /dev/null
	then
		echo "${L_PREFIX} [INFO] mc_stop(): Stopping ${LOCAL_SERVICE}"

		as_user "screen -p 0 -S ${SCREEN_SESSION}_${NUM} -X eval 'stuff \"save-all\"\015'"
		sleep 1

		as_user "screen -p 0 -S ${SCREEN_SESSION}_${NUM} -X eval 'stuff \"stop\"\015'"
		sleep 1

		# Check if the process was successfully stopped
		COUNTER=0
		while [ ${COUNTER} -lt 30 ]; do

			if ! pgrep -u ${USERNAME} -f ${LOCAL_SERVICE} > /dev/null
			then
				L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
				L_PREFIX="${L_TIMESTAMP}"
				echo "${L_PREFIX} [INFO] mc_stop(): ${LOCAL_SERVICE} has been stopped"

				break
			fi

			sleep 1

			((COUNTER += 1))
		done

		if [ ${COUNTER} -ge 30 ]
		then
			L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
			L_PREFIX="${L_TIMESTAMP}"

			echo "${L_PREFIX} [ERROR] mc_stop(): ${LOCAL_SERVICE} could not be stopped"
		fi
	else
		echo "${L_PREFIX} [WARNING] mc_stop(): ${LOCAL_SERVICE} was not running"
	fi
}


mc_pregen() {
	L_TIMESTAMP=`date "+%Y-%m-%d %H:%M:%S"`
	L_PREFIX="${L_TIMESTAMP}"

	#NUM=`printf %02d ${i}`
	NUM="${1}"
	LOCAL_SERVICE="${SERVICE}_${NUM}.jar"

	# Check that the process is running
	if pgrep -u ${USERNAME} -f ${LOCAL_SERVICE} > /dev/null
	then
		echo "${L_PREFIX} [INFO] mc_pregen(): Starting pregen on ${LOCAL_SERVICE}"

		as_user "screen -p 0 -S ${SCREEN_SESSION}_${NUM} -X eval 'stuff \"${2}\"\015'"

	else
		echo "${L_PREFIX} [WARNING] mc_pregen(): ${LOCAL_SERVICE} was not running"
	fi
}


mc_move_regions() {
	if [ ! -d "${COMBINED_WORLD_DIR}/region" ]
	then
		mkdir -p "${COMBINED_WORLD_DIR}/region"
	fi

	SERVER=1
	for i in `seq 0 3`;
	do
		((XS = ($i - 2) * 25))
		((XE = $XS + 24))

		for j in `seq 0 3`;
		do
			NUM=`printf %02d ${SERVER}`
			cd "${DST_DIR}/server_${NUM}/${WORLD_DIR}/region/"
			echo "server ${NUM}"

			((ZS = ($j - 2) * 25))
			((ZE = $ZS + 24))

			for x in `seq $XS $XE`;
			do
				for z in `seq $ZS $ZE`;
				do
					#echo "mv -n r.${x}.${z}.mca ${COMBINED_WORLD_DIR}/region/"
					mv -n "r.${x}.${z}.mca" "${COMBINED_WORLD_DIR}/region/"
				done
			done

			((SERVER += 1))
		done
	done
}

# Process the commands
case "${1}" in
	create_all)
		mc_create_instances 16
		;;
	start_all)
		for i in `seq 1 16`;
		do
			mc_start $i
		done
		;;
	stop_all)
		for i in `seq 1 16`;
		do
			mc_stop $i
		done
		;;
	pregen_all)
		mc_pregen "01" "pregen 0 -1600 -801 -1600 -801"
		mc_pregen "02" "pregen 0 -1600 -801 -800 -1"
		mc_pregen "03" "pregen 0 -1600 -801 0 799"
		mc_pregen "04" "pregen 0 -1600 -801 800 1599"
		mc_pregen "05" "pregen 0 -800 -1 -1600 -801"
		mc_pregen "06" "pregen 0 -800 -1 -800 -1"
		mc_pregen "07" "pregen 0 -800 -1 0 799"
		mc_pregen "08" "pregen 0 -800 -1 800 1599"
		mc_pregen "09" "pregen 0 0 799 -1600 -801"
		mc_pregen "10" "pregen 0 0 799 -800 -1"
		mc_pregen "11" "pregen 0 0 799 0 799"
		mc_pregen "12" "pregen 0 0 799 800 1599"
		mc_pregen "13" "pregen 0 800 1599 -1600 -801"
		mc_pregen "14" "pregen 0 800 1599 -800 -1"
		mc_pregen "15" "pregen 0 800 1599 0 799"
		mc_pregen "16" "pregen 0 800 1599 800 1599"
		;;
	move_regions)
		mc_move_regions
		;;
	*)
		echo "Usage: /etc/init.d/minecraft {create_all|start_all|stop_all|pregen_all \"server command\"}"
		exit 1
		;;
esac

exit 0