pydantic settings customized sources

main.py

import os
from pydantic import BaseSettings

os.environ["VALUE"] = "2"


def record_call(func):
    def wrapper(*args, **kwargs):
        print(f"Calling {func.__class__.__name__}")
        result = func(*args, **kwargs)
        print(f"Returned {result}")
        return result

    return wrapper


def custom_settings(settings):
    return {"value": 4}


class Settings(BaseSettings):

    value: int

    class Config:
        @classmethod
        def customise_sources(cls, init_settings, env_settings, file_secret_settings):

            return (
                record_call(init_settings),
                record_call(env_settings),
                record_call(file_secret_settings),
                record_call(custom_settings),
            )


settings = Settings(value=1)

print("Value:", settings.value)

stdout

Calling InitSettingsSource
Returned {'value': 1}
Calling EnvSettingsSource
Returned {'value': '2'}
Calling SecretsSettingsSource
Returned {}
Calling function
Returned {'value': 4}
Value: 1