программа, которую я пишу для кого-то, должна быть в состоянии определить, подключен ли сервер Minecraft к сети или нет. Было бы также хорошо, если бы он мог сказать, сколько игроков или какие игроки онлайн. Я не уверен, как работают серверы Minecraft в этом смысле, поэтому я не уверен, как это сделать. Если вам нужен конкретный IP адрес, вы можете написать мне, хотя я не уверен, что мне разрешено публиковать его здесь.

Для мониторинга я бы проверил, есть ли уже сценарий Nagios, который может делать то, что вы хотите.

Оказывается, плагин Minecraft Server Nagios уже существует check_minecraft.py.

Скачать

wget 'https://raw.githubusercontent.com/vertecx/nagios-plugins/master/check_minecraft.py'

Справка по использованию

deltik@node51 [~]$ python check_minecraft.py -h
usage: check_minecraft.py [-h] -H ADDRESS [-p INTEGER] [-n INTEGER]
                          [-m STRING] [-f] [-w DOUBLE] [-c DOUBLE] [-t DOUBLE]
                          [-v]

This plugin will try to connect to a Minecraft server.

optional arguments:
  -h, --help            show this help message and exit
  -H ADDRESS, --hostname ADDRESS
                        host name or IP address
  -p INTEGER, --port INTEGER
                        port number (default: 25565)
  -n INTEGER, --number-of-checks INTEGER
                        number of checks to get stable average response time
                        (default: 5)
  -m STRING, --motd STRING
                        expected motd in server response (default: A Minecraft
                        Server)
  -f, --warn-on-full    generate warning if server is full
  -w DOUBLE, --warning DOUBLE
                        response time to result in warning status (seconds)
  -c DOUBLE, --critical DOUBLE
                        response time to result in critical status (seconds)
  -t DOUBLE, --timeout DOUBLE
                        seconds before connection times out (default: 10)
  -v, --verbose         show details for command-line debugging (Nagios may
                        truncate output)
MINECRAFT UNKNOWN: Invalid arguments

Пример использования

Проверьте, что mc.deltik.orgвозвращает ожидаемое MOTD (сообщение дня) Deltik Minecraft Server:

deltik@node51 [~] python check_minecraft.py -H mc.deltik.org -m "Deltik Minecraft Server"
MINECRAFT OK: 0/20 players online - 300 bytes in 0.0345 second response time|time=0.0345476s;0.0;0.0;0.0;10.0

Ресурсы

check_minecraft.py воспроизводится здесь во всей полноте:

#!/usr/bin/env python
# coding=utf8

from datetime import datetime, timedelta
import sys, string, socket, time, argparse

# Exit statuses recognized by Nagios.
STATE_OK = 0
STATE_WARNING = 1
STATE_CRITICAL = 2
STATE_UNKNOWN = 3

# Output formatting string.
OUTPUT_OK = "MINECRAFT OK: {0} - {1} bytes in {2:.3} second response time|time={2}s;{3};{4};0.0;{5}"
OUTPUT_WARNING = "MINECRAFT WARNING: {0} - {1} bytes in {2:.3} second response time|time={2}s;{3};{4};0.0;{5}"
OUTPUT_CRITICAL = "MINECRAFT CRITICAL: {0} - {1} bytes in {2:.3} second response time|time={2}s;{3};{4};0.0;{5}"
OUTPUT_EXCEPTION = "MINECRAFT CRITICAL: {0}"
OUTPUT_UNKNOWN = "MINECRAFT UNKNOWN: Invalid arguments"

# Minecraft packet ID:s, delimiters and encoding.
MC_SERVER_LIST_PING = "\xfe"
MC_DISCONNECT = "\xff"
MC_DELIMITER = u"\xa7"
MC_ENCODING = "utf-16be"

def log(start, message):
    print("{0}: {1}".format(datetime.now() - start, message))

def get_server_info(host, port, num_checks, timeout, verbose):
    start_time = datetime.now()
    total_delta = timedelta()
    byte_count = len(MC_SERVER_LIST_PING) * num_checks

    # Contact the server multiple times to get a stable average response time.
    for i in range(0, num_checks):
        if (verbose): iteration = "Iteration {0}/{1}: ".format(i + 1, num_checks)

        # Save start time and connect to server.
        if (verbose): log(start_time, "{0}Connecting to {1} on port {2}.".format(iteration, host, port))
        net_start_time = datetime.now()
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.settimeout(timeout)
        s.connect((host, port))

        # Send Minecraft Server List Ping packet.
        if (verbose): log(start_time, "{0}Sending Server List Ping.".format(iteration))
        s.send(MC_SERVER_LIST_PING)

        # Receive answer from server. The largest answer returned by the server that also works with the Minecraft client
        # seems to be around 520 bytes (259 unicode character at 2 bytes each plus one start byte and one length byte).
        if (verbose): log(start_time, "{0}Receiving data...".format(iteration))
        data = s.recv(550)
        data_len = len(data)
        byte_count += data_len
        if (verbose): log(start_time, "{0}Received {1} bytes".format(iteration, data_len))

        s.close()

        # Check if returned data seems valid. If not, throw AssertionError exception.
        if (verbose):
            if (data[0] == MC_DISCONNECT):
                log(start_time, "Returned data seems valid.")
            else:
                log(start_time, "Returned data is invalid. First byte is {0:#x}.".format(ord(data[0])))

        assert data[0] == MC_DISCONNECT

        # Save response time for later average calculation.
        delta = datetime.now() - net_start_time
        total_delta += delta

        time.sleep(0.1)

    # Calculate the average response time in seconds
    total_response = total_delta.seconds + total_delta.microseconds / 1000000.0
    average_response = total_response / num_checks

    # Decode and split returned skipping the first two bytes.
    info = data[3:].decode(MC_ENCODING).split(MC_DELIMITER)
    motd = info[:]
    del motd[-1] # removing max_players
    del motd[-1] # removing players
    motd = ''.join(motd).replace("\n","") # removing newlines

    return {'motd': motd,
            'players': int(info[-2]),
            'max_players': int(info[-1]),
            'byte_count': byte_count,
            'response_time': average_response}

def main():
    parser = argparse.ArgumentParser(description="This plugin will try to connect to a Minecraft server.");

    parser.add_argument('-H', '--hostname', dest='hostname', metavar='ADDRESS', required=True, help="host name or IP address")
    parser.add_argument('-p', '--port', dest='port', type=int, default=25565, metavar='INTEGER', help="port number (default: 25565)")
    parser.add_argument('-n', '--number-of-checks', dest='num_checks', type=int, default=5, metavar='INTEGER', help="number of checks to get stable average response time (default: 5)")
    parser.add_argument('-m', '--motd', dest='motd', default='A Minecraft Server', metavar='STRING', help="expected motd in server response (default: A Minecraft Server)")
    parser.add_argument('-f', '--warn-on-full', dest='full', action='store_true', help="generate warning if server is full")
    parser.add_argument('-w', '--warning', dest='warning', type=float, default=0.0, metavar='DOUBLE', help="response time to result in warning status (seconds)")
    parser.add_argument('-c', '--critical', dest='critical', type=float, default=0.0, metavar='DOUBLE', help="response time to result in critical status (seconds)")
    parser.add_argument('-t', '--timeout', dest='timeout', type=float, default=10.0, metavar='DOUBLE', help="seconds before connection times out (default: 10)")
    parser.add_argument('-v', '--verbose', dest='verbose', action='store_true', help="show details for command-line debugging (Nagios may truncate output)")

    # Parse the arguments. If it failes, exit overriding exit code.
    try:
        args = parser.parse_args()
    except SystemExit:
        print(OUTPUT_UNKNOWN)
        sys.exit(STATE_UNKNOWN)

    try:
        info = get_server_info(args.hostname, args.port, args.num_checks, args.timeout, args.verbose)

        if string.find(info['motd'], args.motd) > -1:
            # Check if response time is above critical level.
            if args.critical and info['response_time'] > args.critical:
                print(OUTPUT_CRITICAL.format("{0} second response time".format(info['response_time']), info['byte_count'], info['response_time'], args.warning, args.critical, args.timeout))
                sys.exit(STATE_CRITICAL)

            # Check if response time is above warning level.
            if args.warning and info['response_time'] > args.warning:
                print(OUTPUT_WARNING.format("{0} second response time".format(info['response_time']), info['byte_count'], info['response_time'], args.warning, args.critical, args.timeout))
                sys.exit(STATE_WARNING)

            # Check if server is full.
            if args.full and info['players'] == info['max_players']:
                print(OUTPUT_WARNING.format("Server full! {0} players online".format(info['players']), info['byte_count'], info['response_time'], args.warning, args.critical, args.timeout))
                sys.exit(STATE_WARNING)

            print(OUTPUT_OK.format("{0}/{1} players online".format(info['players'], info['max_players']), info['byte_count'], info['response_time'], args.warning, args.critical, args.timeout))
            sys.exit(STATE_OK)

        else:
            print(OUTPUT_WARNING.format("Unexpected MOTD, {0}".format(info['motd']), info['byte_count'], info['response_time'], args.warning, args.critical, args.timeout))
            sys.exit(STATE_WARNING)

    except socket.error as msg:
        print(OUTPUT_EXCEPTION.format(msg))
        sys.exit(STATE_CRITICAL)

    except AssertionError:
        print(OUTPUT_EXCEPTION.format("Invalid data returned by server"))
        sys.exit(STATE_CRITICAL)

    except UnicodeDecodeError:
        print(OUTPUT_EXCEPTION.format("Unable to decode server response"))
        sys.exit(STATE_CRITICAL)

if __name__ == "__main__":
    main()

Текст лицензии:

The MIT License

Copyright (c) 2012-2016 Petter Jönsson

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Похоже, вы могли бы хотеть клиент Minecraft на основе терминала.

Посмотрите на это: https://github.com/ORelio/Minecraft-Console-Client