uvicorn.run env_file Not Passed Correctly

[oliv10]

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Discussion Link

https://github.com/encode/uvicorn/discussions/2328

Description

When passing a .env file with the uvicorn.run command it does not properly pass its information on to the uvicorn and FastAPI application.

Example Code

### Test Code


import uvicorn
import fastapi
from pydantic_settings import BaseSettings
import argparse
import logging
from logging import getLogger


class Settings(BaseSettings):
    DEBUG: bool = False



SETTINGS = Settings()
app = fastapi.FastAPI()



Logger = getLogger("uvicorn")
if SETTINGS.DEBUG:
    Logger.setLevel(logging.DEBUG)
    Logger.debug("Debug Mode Enabled")
else:
    Logger.setLevel(logging.INFO)



@app.get("/")
async def root():
    if SETTINGS.DEBUG:
        return {"message": "DEBUG World"}
    else:
        return {"message": "Hello World"}


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--env-file", type=str, default=".env")
    args = parser.parse_args()
    
    uvicorn.run(app, env_file=args.env_file)

.env file

DEBUG=True

Test Cases

Incorrect Output

python3 ./test_uvicorn.py

INFO:     Loading environment from '.env'
INFO:     Started server process [279760]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     127.0.0.1:40028 - "GET / HTTP/1.1" 200 OK

Correct Output

uvicorn test_uvicorn:app --env-file .env

INFO:     Loading environment from '.env'
DEBUG:    Debug Mode Enabled
INFO:     Started server process [280032]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
DEBUG:    DEBUG
INFO:     127.0.0.1:60288 - "GET / HTTP/1.1" 200 OK

Python, Uvicorn & OS Version

Running uvicorn 0.29.0 with CPython 3.12.2 on Linux

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[oliv10]

Maybe relates to #1319 and #1372.

[saparmuratx]

I faced similar problem trying to debug my FastAPI project.
uvicorn keeps ignoring specified --env-file

When uvicorn server is launched like this:

uvicorn src.main:app --reload --env-file src/.env 

with specified src/.env,
it seems to ignore specified env file at all and use global environment variables.

After some time trying to fix it, I have found the culprit.
VS Code automatically loads .env file from default workspace folder for Python.

I think if terminal session has environment variables uvicorn will use them regardless of specified .env file. So after changing the .env file, restarting of terminal is required to load new values.