Convert dict-like config to a list of environment variables

config_to_envs.py

"""
Convert a dict-like config to a list of environment variables, discarding values

>>> config_to_envs(dict(
... server=dict(port=8000),
... database=dict(dsn='postgres://postgres:password@host:5432/postgres'),
... debug=True))
['SERVER_PORT', 'DATABASE_DSN', 'DEBUG']

>>> config_to_envs(dict(
... server=dict(port=8000),
... database=dict(dsn='postgres://postgres:password@host:5432/postgres'),
... debug=True), keep_values=True)
['SERVER_PORT=8000', 'DATABASE_DSN=postgres://postgres:password@host:5432/postgres', 'DEBUG=True']
"""

from typing import Dict, List, Union


def config_to_envs(config: Dict, keep_values=False) -> List[str]:
    
    result = []
    def _flatten(cfg: Union[dict, str], name=''):
        if type(cfg) == dict:
            for key, value in cfg.items():
                if name:
                    _flatten(value, name=f'{name.upper()}_{key.upper()}')
                else:
                    _flatten(value, name=key.upper())
        else:
            if keep_values:
                value = cfg
                result.append(f'{name}={value}')
            else:
                result.append(name)

    _flatten(config)
    return result