A simple cascading config reader

config_reader.py

import os, sys, json
from pathlib import Path

class ConfigReader:
    def __init__(self, default=None, **kwargs):
        self.default=default
        self.py_file = Path(os.path.join(os.getcwd(), sys.argv[0])).absolute()
        p = self.py_file.parent
        found_config_json = []
        while p!=Path('/'):
            if (p/"config.json").exists():
                found_config_json.append(p/"config.json")
            p=p.parent
        found_config_json = reversed(found_config_json)
        self.config_json = dict()
        for cfile in found_config_json:
            with cfile.open('r') as f:
                new_config = json.load(f)
                assert type(new_config)==dict
            self.config_jdon=dict(self.config_json, **new_config)
        self.config_args = dict()
        key = None
        for arg in sys.argv:
            if arg.startswith("-"):
                key=arg.strip("-")
            elif key is not None:
                self.config_args[key]=arg
                key = None
        self.config_hard_coded = kwargs

                                                                                                                                                                                                                     def __getitem__(self, key):
        # Look for keys in this order:
        # (1) key-word arguments for the reader
        # (2) Command line argument
        # (3) config.json files (in this folder or above - recursively)
        # (4) Environment variables
        return self.config_hard_coded.get(key, self.config_args.get(key, self.config_json.get(key, os.environ.get(key, self.default))))

config = ConfigReader()

example.py

from config_reader import config

print (config["some_value"])