Argument parser to parse parameters in configuration files. Convenient modification based on command lines are supported.

config_parser.py

import os
import fire
import toml
import yaml


def merge_a_into_b(a, b):
    # merge dict a into dict b. values in a will overwrite b.
    for k, v in a.items():
        if isinstance(v, dict) and k in b:
            assert isinstance(
                b[k], dict
            ), "Cannot inherit key '{}' from base!".format(k)
            merge_a_into_b(v, b[k])
        else:
            b[k] = v


def load_config(config_file):
    with open(config_file, "r") as reader:
        config = yaml.load(reader, Loader=yaml.FullLoader)
    if "inherit_from" in config:
        base_config_file = config["inherit_from"]
        base_config_file = os.path.join(
            os.path.dirname(config_file), base_config_file
        )
        assert not os.path.samefile(config_file, base_config_file), \
            "inherit from itself"
        base_config = load_config(base_config_file)
        del config["inherit_from"]
        merge_a_into_b(config, base_config)
        return base_config
    return config


def parse_config_cmdargs(config, **cmdargs):
    toml_list = []
    for k, v in cmdargs.items():
        if isinstance(v, str):
            toml_list.append(f"{k}='{v}'")
        elif isinstance(v, bool):
            toml_list.append(f"{k}={str(v).lower()}")
        else:
            toml_list.append(f"{k}={v}")
    toml_str = "\n".join(toml_list)
    cmd_config = toml.loads(toml_str)
    config = load_config(config)
    merge_a_into_b(cmd_config, config)
    return config


if __name__ == '__main__':
    fire.Fire(parse_config_cmdargs)