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