Upgpkg: 1.9-1

Add suspending capability for the minecraft server through the control
script and an additional screen session which listens on the same port
with netcat.
	* Update .conf accordingly
	* IDLE_SERVER can be either true or false
	* The default is no idle server
	* Choose an available netcat flavor automatically
Variable renaming in .install.
Notify the user of kept directories on post_remove and alter ownership
to root before removing the game user.
Print error messages to stderr.

1 files changed, 196 insertions, 68 deletions

diff --git a/minecraftd.sh b/minecraftd.sh
index 8743bd746654..a44d84e6b493 100755
--- a/minecraftd.sh
+++ b/minecraftd.sh
@@ -1,72 +1,177 @@
 #!/bin/bash
 
-source /etc/conf.d/minecraft || echo "Could not source /etc/conf.d/minecraft"
+# The actual program name
+declare -r myname="minecraftd"
+declare -r game="minecraft"
 
 # General rule for the variable-naming-schema:
 # Variables in capital letters may be passed through the command line others not.
-
-# You may use this script for any minecraft server of your choice, just alter the config file
-SERVER_ROOT="${SERVER_ROOT:-/srv/minecraft}"
-BACKUPPATH="${BACKUPPATH:-/srv/minecraft/backup}"
-LOGPATH="${LOGPATH:-/srv/minecraft/logs}"
-WORLDPATHS="${WORLDPATHS:-world}"
-KEEP_BACKUPS="${KEEP_BACKUPS:-10}"
-MC_USER="${MC_USER:-minecraft}"
-MAIN_JAR="${MAIN_JAR:-minecraft_server.jar}"
-SESSION_NAME="${SESSION_NAME:-minecraft}"
-
-# Specify system parameters for the minecraft server
-MINHEAP="${MINHEAP:-512M}"
-MAXHEAP="${MAXHEAP:-1024M}"
-THREADS="${THREADS:-1}"
-JAVA_PARMS="${JAVA_PARMS:-"-Xmx${MAXHEAP} -Xms${MINHEAP} -XX:ParallelGCThreads=${THREADS}"}"
-
-# The actual program name
-declare -r myname="minecraftd"
+# Avoid altering any of those later in the code since they may be readonly.
+
+# You may use this script for any game server of your choice, just alter the config file
+[[ ! -z "${SERVER_ROOT}" ]]  && declare -r SERVER_ROOT=${SERVER_ROOT}   || SERVER_ROOT="/srv/${game}"
+[[ ! -z "${BACKUP_DEST}" ]]  && declare -r BACKUP_DEST=${BACKUP_DEST}   || BACKUP_DEST="/srv/${game}/backup"
+[[ ! -z "${LOGPATH}" ]]      && declare -r LOGPATH=${LOGPATH}           || LOGPATH="/srv/${game}/logs"
+[[ ! -z "${BACKUP_PATHS}" ]] && declare -r BACKUP_PATHS=${BACKUP_PATHS} || BACKUP_PATHS="world"
+[[ ! -z "${KEEP_BACKUPS}" ]] && declare -r KEEP_BACKUPS=${KEEP_BACKUPS} || KEEP_BACKUPS="10"
+[[ ! -z "${GAME_USER}" ]]    && declare -r GAME_USER=${GAME_USER}       || GAME_USER="minecraft"
+[[ ! -z "${MAIN_EXECUTABLE}" ]] && declare -r MAIN_EXECUTABLE=${MAIN_EXECUTABLE} || MAIN_EXECUTABLE="minecraft_server.jar"
+[[ ! -z "${SESSION_NAME}" ]] && declare -r SESSION_NAME=${SESSION_NAME} || SESSION_NAME="${game}"
+
+# System parameters for java
+[[ ! -z "${MINHEAP}" ]] && declare -r MINHEAP=${MINHEAP} || MINHEAP="512M"
+[[ ! -z "${MAXHEAP}" ]] && declare -r MAXHEAP=${MAXHEAP} || MAXHEAP="1024M"
+[[ ! -z "${THREADS}" ]] && declare -r THREADS=${THREADS} || THREADS="1"
+[[ ! -z "${JAVA_PARMS}" ]] && declare -r JAVA_PARMS=${JAVA_PARMS} || JAVA_PARMS="-Xmx${MAXHEAP} -Xms${MINHEAP} -XX:ParallelGCThreads=${THREADS}"
+
+# System parameters for the control script
+[[ ! -z "${IDLE_SERVER}" ]]       && declare -r IDLE_SERVER=${IDLE_SERVER}   || IDLE_SERVER="false"
+[[ ! -z "${IDLE_SESSION_NAME}" ]] && declare -r IDLE_SESSION_NAME=${IDLE_SESSION_NAME} || IDLE_SESSION_NAME="idle_server"
+[[ ! -z "${GAME_PORT}" ]]         && declare -r GAME_PORT=${GAME_PORT}       || GAME_PORT="25565"
+[[ ! -z "${CHECK_PLAYER_TIME}" ]] && declare -r CHECK_PLAYER_TIME=${CHECK_PLAYER_TIME} || CHECK_PLAYER_TIME="30"
+[[ ! -z "${IDLE_IF_TIME}" ]]      && declare -r IDLE_IF_TIME=${IDLE_IF_TIME} || IDLE_IF_TIME="1200"
+
+# Variables passed over the command line will always override the one from a config file
+source /etc/conf.d/minecraft || echo "Could not source /etc/conf.d/minecraft"
 
 # Check whether sudo is needed at all
-if [[ $(whoami) == ${MC_USER} ]]; then
+if [[ $(whoami) == ${GAME_USER} ]]; then
 	SUDO_CMD=""
 else
-	SUDO_CMD="sudo -u ${MC_USER}"
+	SUDO_CMD="sudo -u ${GAME_USER}"
+fi
+
+# Choose which flavor of netcat is to be used
+if which netcat &> /dev/null; then
+	NETCAT_CMD="netcat"
+elif which ncat &> /dev/null; then
+	NETCAT_CMD="ncat"
+else
+	NETCAT_CMD=""
 fi
 
 # Check for sudo rigths
-if [[ $(${SUDO_CMD} whoami) != ${MC_USER} ]]; then
-	echo -e "You have \e[39;1mno permission\e[0m to run commands as $MC_USER user."
-	exit 1
+if [[ $(${SUDO_CMD} whoami) != ${GAME_USER} ]]; then
+	>&2 echo -e "You have \e[39;1mno permission\e[0m to run commands as $GAME_USER user."
+	exit 21
 fi
 
-# Pipe any given argument to the minecraft server console
-mc_command() {
+# Pipe any given argument to the game server console
+game_command() {
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -X stuff "`printf \"$*\r\"`"
 }
 
+# Check whether the server is visited by a player otherwise shut it down
+idle_server_daemon() {
+	# This function is run within a screen session of the GAME_USER therefore SUDO_CMD can be omitted
+	if [[ $(whoami) != ${GAME_USER} ]]; then
+		>&2 echo "Somehow this hidden function was not executed by the ${GAME_USER} user."
+		>&2 echo "This should not have happend. Are you messing around with this script? :P"
+		exit 22
+	fi
+
+	# Time in seconds for which no player was on the server
+	no_player=0
+
+	while true; do
+		screen -S "${SESSION_NAME}" -Q select . > /dev/null
+		if [[ $? -eq 0 ]]; then
+			# Game server is up and running
+			screen -S "${SESSION_NAME}" -X stuff "`printf \"list\r\"`"
+			# The "player_delimiter" in awk print needs to be 6 for the spigot server
+			# since the according information is contained in the 6th not in th 4th column
+			if [[ -z $(tail -n 1 "${LOGPATH}/latest.log" | awk '{ print $4 }') ]]; then
+				# No player was seen on the server through list
+				no_player=$((no_player + CHECK_PLAYER_TIME))
+				# Stop the game server if no player was active for at least ${IDLE_IF_TIME}
+				[[ "${no_player}" -ge "${IDLE_IF_TIME}" ]] && IDLE_SERVER="false" ${myname} stop
+			else
+				no_player=0
+				# Retry in ${CHECK_PLAYER_TIME} seconds
+				sleep ${CHECK_PLAYER_TIME}
+			fi
+		else
+			# Game server is down, listen on port ${GAME_PORT} for incoming connections
+			echo "Netcat is listening on port ${GAME_PORT} for incoming connections..."
+			${NETCAT_CMD} -v -l ${GAME_PORT}
+			echo "Netcat caught an connection. The server is coming up again...."
+			IDLE_SERVER="false" ${myname} start
+			sleep ${CHECK_PLAYER_TIME}
+		fi
+	done
+}
+
 # Start the server if it is not already running
 server_start() {
+	# Start the game server
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -Q select . > /dev/null
 	if [[ $? -eq 0 ]]; then
 		echo "A screen ${SESSION_NAME} session is already running. Please close it first."
 	else
 		echo -en "Starting server... "
-		${SUDO_CMD} screen -dmS "${SESSION_NAME}" /bin/bash -c "cd '${SERVER_ROOT}'; java ${JAVA_PARMS} -jar '${SERVER_ROOT}/${MAIN_JAR}' nogui"
+		${SUDO_CMD} screen -dmS "${SESSION_NAME}" /bin/bash -c "cd '${SERVER_ROOT}'; java ${JAVA_PARMS} -jar '${SERVER_ROOT}/${MAIN_EXECUTABLE}' nogui"
 		echo -e "\e[39;1m done\e[0m"
 	fi
+
+	if [[ "${IDLE_SERVER}" == "true" ]]; then
+		# Check for the availability of the netcat (nc) binaries
+		if [[ -z "${NETCAT_CMD}" ]]; then
+			>&2 echo "The netcat binaries are needed for suspending an idle server."
+			exit 12
+		fi
+
+		# Start the idle server daemon
+		${SUDO_CMD} screen -S "${IDLE_SESSION_NAME}" -Q select . > /dev/null
+		if [[ $? -eq 0 ]]; then
+			echo "An idles server screen session called ${IDLE_SESSION_NAME} is already running. Please close it first."
+		else
+			echo -en "Starting idle server daeomon... "
+			${SUDO_CMD} screen -dmS "${IDLE_SESSION_NAME}" /bin/bash -c "${myname} idle_server_daemon"
+			echo -e "\e[39;1m done\e[0m"
+		fi
+	else
+		# Though IDLE_SERVER is not set to true it could still be running and just have not noticed that the
+		# server was started, e.g. by manually triggering server_start again. Therefore reset the idle daemon.
+		${SUDO_CMD} screen -S "${IDLE_SESSION_NAME}" -Q select . > /dev/null
+		if [[ $? -eq 0 ]]; then
+			${SUDO_CMD} screen -S "${IDLE_SESSION_NAME}" -X quit
+		fi
+		${SUDO_CMD} screen -dmS "${IDLE_SESSION_NAME}" /bin/bash -c "${myname} idle_server_daemon"
+	fi
 }
 
 # Stop the server gracefully by saving everything prior and warning the users
 server_stop() {
+	# Quit the idle daemon
+	if [[ "${IDLE_SERVER}" == "true" ]]; then
+		# Check for the availability of the netcat (nc) binaries
+		if [[ -z "${NETCAT_CMD}" ]]; then
+			>&2 echo "The netcat binaries are needed for suspending an idle server."
+			exit 12
+		fi
+
+		${SUDO_CMD} screen -S "${IDLE_SESSION_NAME}" -Q select . > /dev/null
+		if [[ $? -eq 0 ]]; then
+			echo -en "Stopping idle server daemon... "
+			${SUDO_CMD} screen -S "${IDLE_SESSION_NAME}" -X quit
+			echo -e "\e[39;1m done\e[0m"
+		else
+			echo "The corresponding screen session for ${IDLE_SESSION_NAME} was already dead."
+		fi
+	fi
+
+	# Gracefully exit the game server
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -Q select . > /dev/null
 	if [[ $? -eq 0 ]]; then
-		mc_command save-all
-		mc_command say "Server is going down in 10 seconds! HURRY UP WITH WATHEVER YOU ARE DOING!" # Warning the users
+		game_command save-all
+		game_command say "Server is going down in 10 seconds! HURRY UP WITH WHATEVER YOU ARE DOING!" # Warning the users
 		echo -en "Server is going down in... "
 		for i in $(seq 1 10); do
-			mc_command say "down in... $(expr 10 - $i)"
+			game_command say "down in... $(expr 10 - $i)"
 			echo -n " $(expr 10 - $i)"
 			sleep 1
 		done
-		mc_command stop
+		game_command stop
 		echo -e "\e[39;1m done\e[0m"
 	else
 		echo "The corresponding screen session for ${SESSION_NAME} was already dead."
@@ -75,12 +180,29 @@ server_stop() {
 
 # Print whether the server is running and if so give some information about memory usage and threads
 server_status() {
+	# Print status information about the idle daemon
+	if [[ "${IDLE_SERVER}" == "true" ]]; then
+		# Check for the availability of the netcat (nc) binaries
+		if [[ -z "${NETCAT_CMD}" ]]; then
+			>&2 echo "The netcat binaries are needed for suspending an idle server."
+			exit 12
+		fi
+
+		${SUDO_CMD} screen -S "${IDLE_SESSION_NAME}" -Q select . > /dev/null
+		if [[ $? -eq 0 ]]; then
+			echo -e "Idle server daemon status:\e[39;1m running\e[0m"
+		else
+			echo -e "Idle server daemon status:\e[39;1m stopped\e[0m"
+		fi
+	fi
+
+	# Print status information for the game server
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -Q select . > /dev/null
 	if [[ $? -eq 0 ]]; then
 		echo -e "Status:\e[39;1m running\e[0m"
 
 		# Calculating memory usage
-		for p in $(${SUDO_CMD} pgrep -f "${MAIN_JAR}"); do
+		for p in $(${SUDO_CMD} pgrep -f "${MAIN_EXECUTABLE}"); do
 			ps -p${p} -O rss | tail -n1;
 		done | gawk '{ count ++; sum += $2 }; END {count --; print "Number of processes =", count, "(screen, bash,", count-2, "x java)"; print "Total memory usage =", sum/1024, "MB" ;};'
 	else
@@ -100,34 +222,34 @@ server_restart() {
 	fi
 }
 
-# Backup the directories specified in $WORLDPATHS
+# Backup the directories specified in BACKUP_PATHS
 backup_files() {
 	# Check for the availability of the tar binaries
 	which tar &> /dev/null
 	if [[ $? -ne 0 ]]; then
-		echo "The tar binaries are needed for a backup."
-		exit 2
+		>&2 echo "The tar binaries are needed for a backup."
+		exit 11
 	fi
 
 	echo "Starting backup..."
 	FILE="$(date +%Y_%m_%d_%H.%M.%S).tar.gz"
-	${SUDO_CMD} mkdir -p "${BACKUPPATH}"
+	${SUDO_CMD} mkdir -p "${BACKUP_DEST}"
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -Q select . > /dev/null
 	if [[ $? -eq 0 ]]; then
-		mc_command save-off
-		mc_command save-all
+		game_command save-off
+		game_command save-all
 		sync && wait
-		${SUDO_CMD} tar -C "${SERVER_ROOT}" -czf "${BACKUPPATH}/${FILE}" --totals ${WORLDPATHS} 2>&1 | grep -v "tar: Removing leading "
-		mc_command save-on
+		${SUDO_CMD} tar -C "${SERVER_ROOT}" -czf "${BACKUP_DEST}/${FILE}" --totals ${BACKUP_PATHS} 2>&1 | grep -v "tar: Removing leading "
+		game_command save-on
 	else
-		${SUDO_CMD} tar -C "${SERVER_ROOT}" -czf "${BACKUPPATH}/${FILE}" --totals ${WORLDPATHS} 2>&1 | grep -v "tar: Removing leading "
+		${SUDO_CMD} tar -C "${SERVER_ROOT}" -czf "${BACKUP_DEST}/${FILE}" --totals ${BACKUP_PATHS} 2>&1 | grep -v "tar: Removing leading "
 	fi
 	echo -e "\e[39;1mbackup completed\e[0m\n"
 
 	echo -n "Only keeping the last ${KEEP_BACKUPS} backups and removing the other ones..."
-	BACKUP_COUNT=$(for f in "${BACKUPPATH}"/[0-9_.]*; do echo ${f}; done | wc -l)
+	BACKUP_COUNT=$(for f in "${BACKUP_DEST}"/[0-9_.]*; do echo ${f}; done | wc -l)
 	if [[ $(expr ${BACKUP_COUNT} - ${KEEP_BACKUPS}) -gt 0 ]]; then
-		${SUDO_CMD} rm $(for f in "${BACKUPPATH}"/[0-9_.]*; do echo ${f}; done | head -n$(expr ${BACKUP_COUNT} - ${KEEP_BACKUPS}))
+		${SUDO_CMD} rm $(for f in "${BACKUP_DEST}"/[0-9_.]*; do echo ${f}; done | head -n$(expr ${BACKUP_COUNT} - ${KEEP_BACKUPS}))
 		echo -e "\e[39;1m done\e[0m ($(expr ${BACKUP_COUNT} - ${KEEP_BACKUPS}) backup(s) pruned)"
 	else
 		echo -e "\e[39;1m done\e[0m (no backups pruned)"
@@ -139,14 +261,14 @@ backup_restore() {
 	# Check for the availability of the tar binaries
 	which tar &> /dev/null
 	if [[ $? -ne 0 ]]; then
-		echo "The tar binaries are needed for a backup."
-		exit 2
+		>&2 echo "The tar binaries are needed for a backup."
+		exit 11
 	fi
 
 	# Only allow the user to restore a backup if the server is down
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -Q select . > /dev/null
 	if [[ $? -eq 0 ]]; then
-		echo -e "The \e[39;1mserver should be down\e[0m in order to restore the world data."
+		>&2 echo -e "The \e[39;1mserver should be down\e[0m in order to restore the world data."
 		exit 3
 	fi
 
@@ -154,7 +276,7 @@ backup_restore() {
 	if [[ $# -lt 1 ]]; then
 		echo "Please enter the corresponding number for the backup to be restored: "
 		i=1
-		for f in "${BACKUPPATH}"/[0-9_.]*; do
+		for f in "${BACKUP_DEST}"/[0-9_.]*; do
 			echo -e "    \e[39;1m$i)\e[0m\t$f"
 			i=$((i+1))
 		done
@@ -166,16 +288,16 @@ backup_restore() {
 		# Interpeting the input
 		if [[ $user_choice =~ ^-?[0-9]+$ ]]; then
 			n=1
-			for f in "${BACKUPPATH}"/[0-9_.]*; do
+			for f in "${BACKUP_DEST}"/[0-9_.]*; do
 				[[ ${n} -eq $user_choice ]] && FILE="$f"
 				n=$((n+1))
 			done
 			if [[ -z $FILE ]]; then
-				echo -e "\e[39;1mFailed\e[0m to interpret your input. Please enter the digit of the presented options."
+				>&2 echo -e "\e[39;1mFailed\e[0m to interpret your input. Please enter the digit of the presented options."
 				exit 5
 			fi
 		else
-			echo -e "\e[39;1mFailed\e[0m to interpret your input. Please enter a valid digit for one of the presented options."
+			>&2 echo -e "\e[39;1mFailed\e[0m to interpret your input. Please enter a valid digit for one of the presented options."
 			exit 6
 		fi
 	elif [[ $# -eq 1 ]]; then
@@ -183,17 +305,17 @@ backup_restore() {
 		if [[ -f "$1" ]]; then
 			FILE="$1"
 		else
-			if [[ -f "${BACKUPPATH}"/"$1" ]]; then
-				FILE="${BACKUPPATH}"/"$1"
+			if [[ -f "${BACKUP_DEST}"/"$1" ]]; then
+				FILE="${BACKUP_DEST}"/"$1"
 			else
-				echo -e "Sorry, but '$1', is \e[39;1mnot a valid file\e[0m, neither in your current directory nor in the backup folder."
+				>&2 echo -e "Sorry, but '$1', is \e[39;1mnot a valid file\e[0m, neither in your current directory nor in the backup folder."
 				exit 4
 			fi
 		fi
 	elif [[ $# -gt 1 ]]; then
-		echo -e "\e[39;1mToo many arguments.\e[0m Please pass only the filename for the world data as an argument."
-		echo "Or alternatively no arguments at all to chose from a list of available backups."
-		exit 1
+		>&2 echo -e "\e[39;1mToo many arguments.\e[0m Please pass only the filename for the world data as an argument."
+		>&2 echo "Or alternatively no arguments at all to chose from a list of available backups."
+		exit 7
 	fi
 
 	echo "Restoring backup..."
@@ -205,10 +327,10 @@ backup_restore() {
 	fi
 }
 
-# Run the given comman at the minecraft server console
+# Run the given comman at the game server console
 server_command() {
 	if [[ $# -lt 1 ]]; then
-		echo "No server command specified. Try 'help' for a list of commands."
+		>&2 echo "No server command specified. Try 'help' for a list of commands."
 		exit 1
 	fi
 
@@ -216,14 +338,14 @@ server_command() {
 	if [[ $? -eq 0 ]]; then
 		sleep 0.1s &
 		sleep_pid=$!
-		mc_command "$@" &
+		game_command "$@" &
 		tail -f --pid=${sleep_pid} -n 0 "${LOGPATH}/latest.log"
 	else
 		echo "There is no ${SESSION_NAME} session to connect to."
 	fi
 }
 
-# Enter the screen minecraft session
+# Enter the screen game session
 server_console() {
 	${SUDO_CMD} screen -S "${SESSION_NAME}" -Q select . > /dev/null
 	if [[ $? -eq 0 ]]; then
@@ -236,17 +358,17 @@ server_console() {
 # Help function, no arguments required
 help() {
 	cat <<-EOF
-	This script was design to easily control any minecraft server. Quite every parameter for a given
-	minecraft server derivative can be altered by editing the variables in the configuration file.
+	This script was design to easily control any ${game} server. Quite every parameter for a given
+	${game} server derivative can be altered by editing the variables in the configuration file.
 
-	Usage: $myname {start|stop|status|backup|restore|command <command>|console}
-	    start                Start the minecraft server
-	    stop                 Stop the minecraft server
-	    restart              Restart the minecraft server
+	Usage: ${myname} {start|stop|status|backup|restore|command <command>|console}
+	    start                Start the ${game} server
+	    stop                 Stop the ${game} server
+	    restart              Restart the ${game} server
 	    status               Print some status information
 	    backup               Backup the world data
 	    restore [filename]   Restore the world data from a backup
-	    command <command>    Run the given comman at the minecraft server console
+	    command <command>    Run the given comman at the ${game} server console
 	    console              Enter the server console through a screen session
 
 	Copyright (c) Gordian Edenhofer <gordian.edenhofer@gmail.com>
@@ -286,8 +408,14 @@ case "$1" in
 	backup_restore "${@:2}"
 	;;
 
+	idle_server_daemon)
+	# This shell be a hidden function which should only be invoced internally
+	idle_server_daemon
+	;;
+
 	*|-h|--help)
 	help
+	exit 0
 esac
 
 exit 0