FastApi settings / dependency

Question

I have a FastAPI app with pydantic settings instance reading and validation env variables:

### config.py
from pydantic import BaseSettings
class Settings(BaseSettings):
    VERSION: str
    OPENAPI_PREFIX: str
settings = Settings()

### main.py
from fastapi import FastApi
from .config import settings
app = FastAPI(
    title='projectX',
    description="my description",
    version=settings.VERSION,
    root_path=settings.OPENAPI_PREFIX,
    openapi_url="/openapi.json",
    prefix="/api"
) 

if I want to use dependency injection, (for testing purpose to override the dependency settings) as showed in this section of the docs , how do I go for:

1. settings.VERSION within FastAPI constructor?

2. any other references to settings outside the endpoints views functions ? Should I put them as dependencies for each endpoint (very repetitive code I believe) ? or go for a middleware ? see here a very similar situation.

Answer 1

If you pass the settings.VERSION into the FastAPI constructor only changed the app version it does not change your API version. To handle each endpoint you would use a router with each dependency to group and form that endpoint with the same dependency. You would check out what I did before through the below image. During this example I was using APIRouter to form a group of router and define a series of deps called Deps.