minecraft-server-purpur

#!/bin/bash
#
# Minecraft Java Edition Server
#
# Copyright (C) 2020 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
# License: GPLv3 or later, at your choice. See <http://www.gnu.org/licenses/gpl>
#
# TODO: use file socket for stdin: https://unix.stackexchange.com/a/612118/4919
# TODO: explore alternatives: named pipes on stdin; tail -f | java, etc
# TODO: FHS paths: server/$HOME in /usr/lib/minecraft, worlds in /var/minecraft/*
# TODO: Multi-world: /var/minecraft/<name>, per-world server.properties (port, name, etc)
#
# References:
# server.jar CLI:
#   https://minecraft.fandom.com/wiki/Tutorials/Setting_up_a_server#Minecraft_options
#   https://www.spigotmc.org/wiki/start-up-parameters/
# vanilla server: https://launchermeta.mojang.com/mc/game/version_manifest.json
# mcrcon: https://linuxize.com/post/how-to-install-minecraft-server-on-ubuntu-18-04/
# ideas: https://minecraftservercontrol.github.io/docs/mscs
#   multi-world (and multi-user)
#   logrotate
#   stdin: tail -f | java
###############################################################################

DESCRIPTION='Minecraft Java Purpur Server'
ARGS='[DIR] [USER] [SEED] [JAVA_ARGS]'

setuplib=${SETUP_LIB_PATH:-"$(dirname "$(readlink -f "$0")")"/../setuplib}
# shellcheck source=../setuplib
if [[ -r "$setuplib" ]]; then source "$setuplib"; else
	echo "Setup library not found: $setuplib" >&2; exit 1;
fi

include java

#------------------------------------------------------------------------------

SETUP_MINECRAFT_SERVER_JAVA_ARGS=(-Xmx4G -Xms4G)

data_dir=${1:-${SETUP_MINECRAFT_SERVER_DIR:-/opt/minecraft-server}}; argument "$data_dir" DIR
user=${2:-${SETUP_MINECRAFT_SERVER_USER:-minecraft}}; argument "$user" USER
seed=${3:-${SETUP_MINECRAFT_SERVER_SEED:-1052397348887568626}}
try shift 3
java_args=("${SETUP_MINECRAFT_SERVER_JAVA_ARGS[@]}")
if (($#)); then java_args=("$@"); fi


#------------------------------------------------------------------------------

url='https://www.minecraft.net/en-us/download/server'
service=minecraft.service

launcher=$data_dir/minecraft-server.sh
eula=$data_dir/eula.txt
props=$data_dir/server.properties
java_home=$data_dir/java

#------------------------------------------------------------------------------


if ! user_exists "$user"; then
	message 'Create Minecraft Server service user'
	# FIXME: Why useradd instead of adduser?
	useropts=(
		--system
		--shell /usr/sbin/nologin
		--home-dir "$data_dir"
		--create-home --skel ""
		--comment "Minecraft Java Server"
	)
	setup_run sudo useradd "${useropts[@]}" -- "$user"
	#mkdir --parents "$data_dir"
	#chown "$user": -- "$data_dir"
fi

message 'Download and extract latest OpenJDK Java'
#setup_run sudo_for "$java_home" rm -rf -- "$java_home"/*
setup_run sudo_for "$java_home" -u "$user" mkdir --parents -- "$java_home"
archive=$(java_download_latest_openjdk "$java_home")
setup_run sudo_for "$java_home" -u "$user" tar -xf "$archive" -C "$java_home" --strip-components=1
#setup_run sudo_for "$archive" rm -- "$archive"

message 'Download latest Purpur Server'
jar=$(download "$(scrape_urls 'https://purpur.pl3x.net/' 'latest/download')" "$data_dir" "$user")
exec=("$java_home"/bin/java "${java_args[@]}" -jar "$jar" --nogui)  # --world-dir "$data_dir"
exit

message 'Initial run to set up config'
# Run once to generate eula.txt and server.properties
# It may emit warnings and errors on first run (files not found)
# and fail on subsequent re-runs (dir is owned by minecraft), that's expected.
if [[ ! -f "$props" ]] || [[ ! -f "$eula" ]]; then
	cd -- "$data_dir"
	sudo -u "$user" "${exec[@]}" --initSettings
fi

if [[ ! -f "$props" ]]; then fatal "server failed to create config files"; fi

# Patch EULA
echo  # that's intentional!
bold "$(head -n1 -- "$eula")"
echo  # and so is this
if ((SETUP_INTERACTIVE)); then
	if ! confirm "Have you read and agreed with Minecraft EULA?"; then
		fatal "Cancelled by user"
	fi
fi
sudo_for "$eula" sed -i '/^eula=false/s/false/TRUE/g' -- "$eula" 2>/dev/null ||
echo 'eula=TRUE' >> "$eula"

# Patch Server Properties
if [[ "$seed" ]] && grep -Fxq -- 'level-seed=' "$props"; then
	bak=$(bakfile "$props")
	backup_file "$props" "$bak"
	awk -v s="$seed" -- \
		'/level-seed=/{sub(/=/, "=" s)}{print}' \
		"$bak" > "$props"
fi


message "Grant ownership to '${user}'"
sudo_for "$data_dir" chown --recursive "$user": -- "$data_dir"


message 'Setup Firewall'
ports=$(awk -F= -v ORS=, '$1~/[-.]port$/{print $2}' "$props")
# FIXME: GameSpy4 Query port is for UDP, not TCP
mkdir -p -- /etc/ufw/applications.d
cat > /etc/ufw/applications.d/minecraft.conf <<-EOF
	[Minecraft]
	title=Minecraft Server (Purpur + RCON + GameSpy4 Query)
	description=Minecraft: Java Edition Purpur Server
	ports=${ports::-1}/tcp
EOF
if exists ufw; then
	ufw allow Minecraft
	ufw reload
fi

message 'Create launcher'
sudo_for "$launcher" tee "$launcher" <<-EOF
	#!/bin/sh
	#
	# By ${SETUP_NAME}
	# https://github.com/MestreLion/seten
	#
	# Copyright (C) 2021 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
	# License: GPLv3 or later, at your choice. See <http://www.gnu.org/licenses/gpl>

	mydir=\$(dirname "\$(readlink -f "\$0")")
	myname=\${0##*/}
	stdin=$XDG_RUNTIME_DIR/stdin

	send() {
	}

	if [ "\$1" = "--help" ]; then
		echo "Minecraft Java Edition Purpur Server"
		echo "Usage: \$myname [--stop]"
		echo "Service: sudo systemctl start ${service}"
		exit
	fi

	if [ "\$1" = "--stop" ]; then
		screen -S minecraft -X stuff "say SERVER SHUTTING DOWN IN 5 SECONDS...\n"
		sleep 5
		screen -S minecraft -X stuff "stop\n"
		exit
	fi

	cd "\$mydir"
	exec "${exec[@]}" "\$@"
EOF
chmod +x "$launcher"

# "Touch" /run/screen
#mkdir -p -m 777 /run/screen
#chmod 777 /run/screen
#sudo -u minecraft screen -DmS minecraft -- true

message 'Create, enable and start Minecraft Server systemd service'
cat > /etc/systemd/system/"$service" <<-EOF
	[Unit]
	Description=Minecraft Java Server
	Documentation=https://github.com/MestreLion/seten
	Wants=network-online.target
	After=network-online.target
	# AssertPathExists=${jar}

	[Service]
	Type=exec
	User=minecraft
	Group=minecraft
	WorkingDirectory=~
	StandardInput=file:stdin

	# https://www.freedesktop.org/software/systemd/man/systemd.exec.html#Sandboxing
	NoNewPrivileges=true
	ProtectHome=true
	PrivateDevices=true
	PrivateTmp=true
	PrivateUsers=true
	ProtectSystem=strict
	# ReadWriteDirectories=$(printf '%q' "$data_dir")

	Restart=on-failure
	RestartSec=5
	# KillMode=none

	# ExecStartPre=/usr/bin/mkfifo ./daemon.in
	ExecStop=$(printf '%q' "$launcher") stop
	ExecStart=$(printf '%q' "$launcher")

	[Install]
	WantedBy=multi-user.target
EOF
systemctl daemon-reload
try systemctl stop "$service"
systemctl enable "$service"
systemctl start "$service"