#!/usr/bin/python3

import sys
import yaml


def print_help():
    print("./config.py <config_file> <key>",
          file=sys.stderr)


def readvalue(config_file, key):

    try:
        with open(config_file, 'r', encoding="utf-8") as f:
            data = yaml.load(f, Loader=yaml.Loader)

        value = data[key]
        print(value)

    except yaml.YAMLError as e:
        print('YAMLError: %s' % e, file=sys.stderr)
    except KeyError as e:
        print('KeyError: %s' % e, file=sys.stderr)


if __name__ == "__main__":
    args = sys.argv[1:]

    if '--help' in args:
        print_help()
        sys.exit(1)

    if len(args) == 2:
        input_file = args[0]
        input_key = args[1]
        readvalue(input_file, input_key)

    elif len(args) < 2:
        print("Error: missing required arguments.",
              file=sys.stderr)
        print_help()
        sys.exit(1)

    else:
        print("Error: too many arguments.",
              file=sys.stderr)
        print_help()
        sys.exit(1)