A python configuration concept.

configuration.py

import toml
import structlog
from pathlib import Path


class InvalidSettingError(ValueError):
    pass


class ConfigurationBase:
    DEFAULT_CONFIG = dict()

    def __init__(self, subclass, **kwargs):
        self.key = subclass.__class__.__name__
        self.value = kwargs
        ConfigurationBase.DEFAULT_CONFIG[self.key] = self.value

    def __repr__(self):
        return f'{self.key}: {self.value}'


class Server(ConfigurationBase):
    def __init__(self, **kwargs):
        super().__init__(self, **kwargs)


class Client(ConfigurationBase):
    def __init__(self, **kwargs):
        super().__init__(self, **kwargs)


class General(ConfigurationBase):
    def __init__(self, **kwargs):
        super().__init__(self, **kwargs)


class Configuration:

    Server(Port='6666', Ip='192.168.50.11')
    Client(Port='6666', Ip='192.168.50.12')
    General(DEBUG_MODE=True)

    CONFIG_DEFAULT = ConfigurationBase.DEFAULT_CONFIG
    _PATH = Path(__file__).parent / 'config.toml'
    logger = structlog.get_logger()

    def __init__(self):

        self.settings = None
        self._load()

    def _load(self):
        if not Configuration._PATH.exists():
            self.logger.info('config.toml file not found.', path=Configuration._PATH)
            self.write_clean_configuration_file()

        self.settings = self._readfile()

        self.logger.info('config.toml loaded.', path=Configuration._PATH)
        for setting in self.settings:
            self.logger.info(f'{setting} settings:', current=self[setting])

    def _readfile(cls):
        with open(cls._PATH, 'r') as file:
            return toml.loads(file.read())

    @classmethod
    def write_clean_configuration_file(cls):
        with open(cls._PATH, 'w') as file:
            file.write(toml.dumps(cls.CONFIG_DEFAULT))
            cls.logger.info('writing clean config.toml file.', path=cls._PATH)

    def __getitem__(self, section):
        try:
            return self.settings[section]
        except KeyError as e:
            raise InvalidSettingError(f'{section} is an invalid configuration key. '
                                      'Use the following configuration keys: ', list(self.settings.keys()))

    def __repr__(self):
        repr = '----CONFIGURATION----\n'
        for key, value in self.settings.items():
            repr += f'{key}: {value}\n'
        return repr


Configuration.write_clean_configuration_file()
config = Configuration()
print(config['Server'])