Does FastAPI support config files with nested structures like yaml?

Question

Python framework FastAPI supports config files of .env style. Can it work with a bit more structured config formats, like .yaml to ini/toml?

Answer 1

While it is not implemented natively in the framework, you can do something like below:

YAML

import os
from pydantic import BaseSettings
import yaml

yaml_settings = dict()

here = os.path.abspath(os.path.dirname(__file__))
with open(os.path.join(here, "settings.yaml")) as f:
    yaml_settings.update(yaml.load(f, Loader=yaml.FullLoader))

class Settings(BaseSettings):
    setting_1: str = yaml_settings['setting_1']
    setting_2: str = yaml_settings['setting_2']

INI

import configparser
import os
from pydantic import BaseSettings

here = os.path.abspath(os.path.dirname(__file__))

config = configparser.ConfigParser()
config.read(os.path.join(here, "settings.ini"))

class Settings(BaseSettings):
   setting_1: str = config['dev']['setting_1']
   setting_2: str = config['dev']['setting_2']

TOML

import toml
import os
from pydantic import BaseSettings

here = os.path.abspath(os.path.dirname(__file__))
toml_settings = toml.load(os.path.join(here, "settings.toml"))

class Settings(BaseSettings):
   setting_1: str = toml_settings['dev']['setting_1']
   setting_2: str = toml_settings['dev']['setting_2']

Then you can pass Settings() in your routes as a dependency.