12factor-configclasses

configclasses

Like dataclasses but for config.

Specify your config with a class and load it with your env vars or env files.

# .env
HOST=0.0.0.0
PORT=8000
...

import httpx
from configclasses import configclass


@configclass
class ClientConfig:
    host: str
    port: int


class UserAPIClient(httpx.AsyncClient):
    def __init__(self, config: ClientConfig, *args, **kwargs):
        self.config = config
        ...
        

config = ClientConfig.from_path(".env")
async with UserAPIClient(config) as client:
    ...

Features

• Fill your configclasses with existent env vars.
• Define default values in case these variables have no value at all.
• Load your config files in env vars following 12factor apps recommendations.
• Support for .env, yaml, toml, ini and json.
• Convert your env vars with specified type in configclass: int, float, str or bool.
• Use nested configclasses to more complex configurations.
• Specify a prefix with @configclass(prefix="<PREFIX>") to append this prefix to your configclass' attribute names.
• Config groups (TODO): https://cli.dev/docs/tutorial/config_groups/

Requirements

Python 3.8+

Installation

Depending on your chosen config file format you can install:

• .env -> pip install 12factor-configclasses[dotenv]
• .yaml -> pip install 12factor-configclasses[yaml]
• .toml -> pip install 12factor-configclasses[toml]
• .ini -> pip install 12factor-configclasses
• .json -> pip install 12factor-configclasses

Or install all supported formats with:

pip install 12factor-configclasses[full]

Usage

There are three ways to use it.

Loading an .env file:

# .env
HOST=0.0.0.0
PORT=8000
DB_URL=sqlite://:memory:
GENERATE_SCHEMAS=True
DEBUG=True
HTTPS_ONLY=False
GZIP=True
SENTRY=False

#config.py
from configclasses import configclass


@configclass
class DB:
    user: str
    password: str
    url: str


@configclass
class AppConfig:
    host: str
    port: int
    db: DB
    generate_schemas: bool
    debug: bool
    https_only: bool
    gzip: bool
    sentry: bool

# app.py
from api.config import AppConfig

app_config = AppConfig.from_path(".env")
app = Starlette(debug=app_config.debug)

if app_config.https_only:
    app.add_middleware(
        HTTPSRedirectMiddleware)
if app_config.gzip:
    app.add_middleware(GZipMiddleware)
if app_config.sentry:
    app.add_middleware(SentryAsgiMiddleware)

...

register_tortoise(
    app,
    db_url=app_config.db.url,
    modules={"models": ["api.models"]},
    generate_schemas=app_config.generate_schemas,
)

if __name__ == "__main__":
    uvicorn.run(app, host=app_config.host, port=app_config.port)

Loading predefined environmental variables:

The same than before, but instead of:

app_config = AppConfig.from_path(".env")

You will do:

app_config = AppConfig.from_environ()

Loading a file from a string:

test_env = """HOST=0.0.0.0
PORT=8000
DB_URL=sqlite://:memory:
GENERATE_SCHEMAS=True
DEBUG=True
HTTPS_ONLY=False
GZIP=True
SENTRY=False"""
app_config = AppConfig.from_string(test_env, ".env")