如何通过命令行将 env 文件传递给 FastAPI 应用程序

Question

I have the following file that reads in an .env file:

from pydantic import BaseSettings, HttpUrl


class Settings(BaseSettings):
    url: HttpUrl

    class Config:
        env_file = "config.env"

settings = Settings()

What do I need to do to be able to pass config.env on start?

So python -m uvicorn main:app --reload --env config.env

Is there any help FastApi or Uvicorn provide for this?

Answer 1

You can pass all the envs from config.env using python-dotenv . To pass a custom path (from): https://stackoverflow.com/a/50356056/14882170

import os
from dotenv import load_dotenv

# Get the path to the directory this file is in
BASEDIR = os.path.abspath(os.path.dirname(__file__))

# Connect the path with your '.env' file name
load_dotenv(os.path.join(BASEDIR, 'config.env'))

test_var = os.getenv("TEST_VAR")

print(test_var)

Answer 2

Because this is your custom code block, so uvicorn or starlette don't support this. I think you should custom your command line by Typer . Then you can pass env file by command line.

Answer 3

From the docs posted here , you need call the variables from the.env class in the Settings class.

config.py

from pydantic import BaseSettings

class Settings(BaseSettings):
foo: str

class Config:
    env_file = "config.env"

where config.env has the following:

foo="bar"

Then you pass the contents to the get_settings function wrapped by a lru_cache decorator and return those values.

@lru_cache()
def get_settings():
  return config.Settings()

After that you can inject those parameters into the "/info" path of the fastapi app:

@app.get("/")
def read_root():
  return {"Hello": "World"}


@app.get("/info")
async def info(settings: config.Settings = Depends(get_settings)):
  return {"foo": settings.foo}

The full main.py should be like this:

from functools import lru_cache
  from fastapi import Depends, FastAPI
  import config

  app = FastAPI()


  @lru_cache()
  def get_settings():
    return config.Settings()


  @app.get("/")
  def read_root():
    return {"Hello": "World"}

  @app.get("/info")
  async def info(settings: config.Settings = Depends(get_settings)):
    return {"foo": settings.foo}

Then just start your app without calling the env file in the command:

python -m uvicorn main:app --reload 

The curl output should be something like this:

curl http://127.0.0.1:8000/info
{"foo":"bar"}