Wrapper script for the official minecraft server (or spigot) to shut it down gracefully via SIGTERM. Useful to put behind systemd and friends.

minecraftd

#!/usr/bin/env python3
from signal import signal, SIG_IGN, SIGTERM, SIGINT
import subprocess
import sys

USAGE = '''Usage: minecraftd [server jar path] [java options]*'''
JAVA_BIN = '/usr/bin/java'
JAVA_OPTS = ['-XX:+UseParNewGC', '-XX:+UseConcMarkSweepGC',
             '-XX:+AggressiveOpts']


def printf(fmt, *args):
    sys.stdout.write(fmt % tuple(args))
    sys.stdout.flush()


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print(USAGE)
        exit(1)
    jar_path = sys.argv[1]
    opts = JAVA_OPTS + sys.argv[2:]
    args = [JAVA_BIN, '-server'] + opts + ['-jar', jar_path, 'nogui']

    printf('minecraftd: %s\n', ' '.join(args))

    def preexec():
        signal(SIGTERM, SIG_IGN)
        signal(SIGINT, SIG_IGN)

    p = subprocess.Popen(args=args, stdin=subprocess.PIPE,
                         preexec_fn=preexec)

    def handler(sig, _):
        printf('minecraftd: stopping server\n')
        p.stdin.write(b'stop\n')
        p.stdin.flush()

    signal(SIGTERM, handler)
    signal(SIGINT, handler)
    p.wait()
    printf('minecraftd: exit code is %d', p.returncode)
    sys.exit(p.returncode)

versionsd

#!/usr/bin/env python3
from datetime import datetime
import os
import subprocess
import sys

WORLDS = ['survival', 'creative']
PATH = '/home/minecraft/worlds'
KEEP_NUM = 168  # one week, every hour


def printf(fmt, *args):
    sys.stdout.write(fmt % tuple(args))
    sys.stdout.flush()


def run(*args):
    subprocess.run(args, stdout=subprocess.DEVNULL)


def btrfs_subvol_snapshot(src, dest):
    run('btrfs', 'subvolume', 'snapshot', '-r', src, dest)


def btrfs_subvol_delete(path):
    run('btrfs', 'subvolume', 'delete', path)


def world_versions(name):
    return '%s.versions' % name


def create_snapshots():
    for world in WORLDS:
        date = datetime.now().strftime('%Y-%m-%d_%H:%M:%S')
        path = os.path.join(PATH, world)
        versions_path = os.path.join(PATH, world_versions(world), date)
        latest_path = os.path.join(PATH, world_versions(world), 'latest')
        printf("versionsd: world %s, creating snapshot %s\n", world,
               versions_path)
        btrfs_subvol_snapshot(path, versions_path)
        printf("versionsd: world %s, updating latest to %s\n", world, date)
        btrfs_subvol_delete(latest_path)
        btrfs_subvol_snapshot(versions_path, latest_path)


def rotate_snapshots():
    for world in WORLDS:
        path = os.path.join(PATH, world_versions(world))
        versions = [snap for snap in os.listdir(path) if snap != 'latest']
        newest = list(sorted(versions, reverse=True))
        to_delete = newest[KEEP_NUM:]
        for snap_path in to_delete:
            snap_abs_path = os.path.join(path, snap_path)
            printf("versionsd: world %s, deleting snapshot %s\n", world,
                   snap_abs_path)
            btrfs_subvol_delete(os.path.join(path, snap_abs_path))


if __name__ == '__main__':
    create_snapshots()
    rotate_snapshots()

thanks, this helped me a lot! I used it to run a Minecraft server in a docker container (docker sends SIGTERM when a container is stopped)

There's a more polished version here