Simple Config class, basically a dict with some enhancements

config.py

# Simple Config class, basically a dict with some enhancements
#
# Best used if you read your config only a couple of times. This version will read in the values everytime.

from functools import reduce
import os.path as path
import yaml

class ConfigValueError(ValueError):
    pass

class DictConfig(dict):
    def __init__(self, **kwargs):
        dict.__init__(self)
        self.update(kwargs)

    def __getitem__(self, key):
        return dict.__getitem__(self, key)

    def __setitem__(self, key, val):
        dict.__setitem__(self, key, val)

    @classmethod
    def value(cls, *keys):
        """Helper to return one single value (may be what ever that value is).

        E.g. Config.value('hubert', 'fly_id')
        """
        try:
            val = reduce(lambda d, k: d[k], keys, cls())

            if isinstance(val, str) and 'UNKOWN' in val:
                raise ConfigValueError('{0} value is not set! Reading {1}'.format(keys, val))
        except KeyError:
            raise ConfigValueError("Could not find a value for the given key: {}".format(keys))

        return val
      
      
class Config(DictConfig):
    DEFAULT_VALUES = {...}
    
    def __init__(self, **kwargs):
        # use this to adjust some stuff. Might be the machine you are running things one, etc.
        super(DictConfig, self).__init__({**Config.DEFAULT_VALUES, **kwargs})
        
# just an example, will probably not work, super depended on your config
class FileConfig(DictConfig):
        def __init__(self, file_path=None):
        super(DictConfig, self).__init__()
        # TODO make this work with windows and unix
        file_path = file_path or path.abspath(path.join(path.dirname(__file__), "../../config/config.yml"))
        
        try:
            with open(file_path, 'r') as f:
                for k, v in yaml.load(f).items():
                    self[k] = v
        except FileNotFoundError:
            raise(FileNotFoundError('could not load master config-file'))