Python script for managing multiple minecraft servers on an VPS

minecraftServerManager.py

# # # # # # # # # # # # # # # # # # # # # # # # # 
#                                               #
#   © 2017 Ringo Hoffmann (zekro Development)   #
#                                               #
#   If you want to use this code, please read   #
#   this first: http://s.zekro.de/codepolicy    #
#                                               #
#   With usage of this code or parts of it in   #
#   any way, you agree to the terms above.      #
#                                               #
# # # # # # # # # # # # # # # # # # # # # # # # # 

import sys
import os
import subprocess
import json
import psutil       # 'pip install psutil'


args = sys.argv
dirs = os.listdir(".")
servers = []
inp = ""

VERSION = "1.3.0"

class Color:
    W  = '\033[0m'  # white (normal)
    R  = '\033[31m' # red
    G  = '\033[32m' # green
    O  = '\033[33m' # orange
    B  = '\033[34m' # blue
    P  = '\033[35m' # purple
    C  = '\033[36m' # cyan

def clr(content, color):
    """
    Returns colored text
    <color> -> type of class Color
    """
    return color + content + Color.W


def error(content):
    """
    Displays red colored error message with button press pause
    """
    print(clr("[ERROR] "+ content, Color.R))
    input()


def isRunning(name):
    """
    Returns boolean if current screen is running by checking
    if 'screen -ls' contains server name
    """
    proc = subprocess.Popen(["screen", "-ls"], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    return name in str(proc.stdout.read())


def clear():
    subprocess.call("clear")


def getSys():
    """
    Retuns system status string from psutil data
    """
    cpulaod = psutil.cpu_percent()                  # CPU-Load in %
    mem = psutil.virtual_memory()                   # Memory data container
    memtotal = mem.total / 1024 / 1024              # Total memory in MiByte
    memused = mem.used / 1024 / 1024                # Used memory in MiByte
    memload = mem.percent                           # Used memory in % of total
    disk = psutil.disk_usage(".")                   # disk usage data container
    disktotal = disk.total / 1024 / 1024 / 1024     # total disk space in GiByte
    diskused = disk.used / 1024 / 1024 / 1024       # used disk space in GiByte
    diskload = disk.percent                         # used disk space in % of total

    return str("CPU load:        %d %%\n"
               "Memory (used):   %d MiB / %d MiB (%d %%)\n"
               "Space (used):    %d GiB / %d GiB (%d %%)"
               % (cpulaod, memused, memtotal, memload, diskused, disktotal, diskload))


def printMenu():
    """
    Printing the main menu and returning the input command
    """
    global servers
    clear()
    print(clr("Server Management System v." + VERSION + " - (c) 2017 zekro\n", Color.C))
    # Print system stats from getSys()
    print("SYSTEM STATS: \n" + getSys() + "\n")
    # collecting local directory names which dont start with '.'
    servers = [d for d in dirs if os.path.isdir(d) and not d.startswith('.')]
    # Printing server table '[STATE] [#] DIRNAME'
    for i, d in enumerate(servers):
        # getting status of server with isRunning(<servername>)
        running = clr("[RUNNING]", Color.G) if isRunning(d) else clr("[STOPPED]", Color.O)
        print("%s  [%d]  %s" % (running, i + 1, d))
    # waiting for console input and retun it
    return input("\nPlease enter a command\nType 'help' for command list\n\n> ")


def getStart(name):
    """
    Getting the start command from <servername>/STARTCMD.txt file
    """
    setfile = name + "/STARTCMD.txt"
    if not os.path.isfile(setfile):
        error("'STARTCMD.txt' was not found!")
        exit()
    else:
        with open(setfile, "r") as f:
            out = f.readline()
        if not out:
            error("No start command was found in 'STARTCMD.txt'!")
            exit()
    return out


def runMain():
    """
    Saving returned console input of printMenu() in global inp var
    This is essential for menu input loop later
    """
    global inp
    inp = printMenu()



# <--------------==[ MAIN PROGRAM ]==-------------->

runMain()

# While 'exit' command was not executed or exception 
# was thrown redraw menue and collect input
while not "exit" in inp:

    invoke = inp.split()[0].lower()
    args = inp.split()[1:]

    if len(args) > 0:

        # COMMAND: 'start <index>'
        # Starting a server by index
        if invoke == "start":
            index = int(args[0]) - 1
            # if index is out of range return error
            if index >= len(servers) or index < 0:
                error("Please enter a valid number!")
            else:
                server = servers[index]
                if isRunning(server):
                    error("This server is currently still running!")
                else:
                    # splitting start command of 'STARTCMD.txt' into arguments
                    command = getStart(server).split()
                    # default start arguments for screen
                    # '-S <servername>' -> setting screen name
                    # '-L' logging cmd output in 'screenlog.0' file
                    start = ["screen", "-S", server, "-L"]
                    os.chdir(server)
                    # injecting start command into screen command arguments
                    for arg in command:
                        start.append(arg)
                    # calling screen process
                    subprocess.call(start)
                    exit()
                    
        # COMMAND: 'stop <index>'
        # Stopping a running server by index
        if invoke == "stop":
            index = int(args[0]) - 1
            if index >= len(servers) or index < 0:
                error("Please enter a valid number!")
            else:
                server = servers[index]
                if not isRunning(server):
                    error("This server is not running!")
                else:
                    # calling 'screen -X -S <screenname> quit' to stop the screen 
                    subprocess.call(["screen", "-X", "-S", server, "quit"])

        # COMMAND: 'resume <index>'
        # Resuming a screen of server by index
        if invoke == "resume":
            index = int(args[0]) - 1
            if index >= len(servers) or index < 0:
                error("Please enter a valid number!")
            else:
                server = servers[index]
                if not isRunning(server):
                    error("This server is not running!")
                else:
                    # resuming screen by command 'screen -r <screenname>'
                    subprocess.call(["screen", "-r", server])
                    exit()



    elif invoke == "help":
        print(
            "\n"
            "start <index>  -  Start a stopped server\n"
            "stop <index>   -  Stop a running server\n"
            "resume <index> -  Resuming a running screen session\n"
            "exit           -  Exit this tool"
            )
        print("[Press any key to continue...]")
        input()

    else:
        error("Please enter a valid command or type 'help' for all commands!")

    runMain()