Config for each environment (for a simple Python SDK)

Question

I have a simple SDK in Python for internal use. It's basically 150~200 lines of code of simple API calls wrapped around nicely that is comfortable for us to use.

It holds a few clients with methods (and each method wraps some API calls).

So a proper usage would be:

from datatube.datatube import Datatube

client = Datatube()
client.do_stuff(...)

Currently it expects 3 environment variables - two for authentication purposes (these are the secret ones) and one for the environment (dev/stg/prod). I want to change the environment variable to be passed on as an argument (seems better). So:

from datatube.datatube import Datatube

client = Datatube('stg')
client.do_stuff(...)

Inside Datatube I'll take the correct config based on the environment. Currently I have:

class BaseConfig:
    pass


class DevelopmentConfig(BaseConfig):
    DATATUBE_URL = 'https://..'



class StagingConfig(BaseConfig):
    DATATUBE_URL = 'https://..'



class ProductionConfig(BaseConfig):
    DATATUBE_URL = 'https://..'



def get_config(env: str):
    env = env.lower()
    if env == 'dev':
        return DevelopmentConfig()
    if env == 'stg':
        return StagingConfig()
    elif env == 'prod':
        return ProductionConfig()
    else:
        raise KeyError(f"unsupported env: {env}. supported environments: dev/stg/prod")

If I'll use type annotation on get_config like:

def get_config(env: str) -> BaseConfig

Then the IDE won't like it (I guess because BaseConfig is empty, but I don't know how to do it nicely - isn't an abstract class kind of an overkill?)

Any recommendations would be helpful.

Using Python 3.9

Answer 1

Class inheritance is overkill here. Just use dataclass instances:

from dataclasses import dataclass


@dataclass
class Config:
    DATATUBE_URL: str


ENVIRONMENTS = {
    'dev': Config(
        DATATUBE_URL='https://..',
    ),
    'stg': Config(
        DATATUBE_URL='https://..',
    ),
    'prd': Config(
        DATATUBE_URL='https://..',
    ),
}


def get_config(env_name: str) -> Config:
    env = ENVIRONMENTS.get(env_name.lower())
    if env is None:
        raise KeyError(
            f"unsupported env: {env_name}. supported environments: " +
            ', '.join(ENVIRONMENTS.keys()))
    return env