dotenv file not loaded correctly

Checklist

• The bug is reproducible against the latest release or master.
• There are no similar issues or pull requests to fix it yet.

Describe the bug

Uvicorn does not load the dot env file as expected when running it via over the command line or via uvicorn.run.

Steps to reproduce the bug

File bug.py:

import uvicorn


if __name__ == '__main__':
    uvicorn.run('bug:app', host='localhost', env_file='.env')

# Uvicorn's example app:
async def app(scope, receive, send):
    assert scope['type'] == 'http'

    await send({
        'type': 'http.response.start',
        'status': 200,
        'headers': [
            [b'content-type', b'text/plain'],
        ],
    })
    await send({
        'type': 'http.response.body',
        'body': b'Hello, world!',
    })

File .env:

UVICORN_PORT=8081
PORT=8081

Shell:

$ uvicorn bug:app --env-file .env
or
$ python bug.py

Output (both times):

/venv/bin/python3.10 /bug.py
INFO:     Loading environment from '.env'
INFO:     Started server process [11355]
INFO:     Waiting for application startup.
INFO:     ASGI 'lifespan' protocol appears unsupported.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://localhost:8000 (Press CTRL+C to quit)

Expected behavior

Server running on port 8081.

Actual behavior

Server running on port 8000:

INFO:     Uvicorn running on http://localhost:8000 (Press CTRL+C to quit)

Debugging material

No response

Environment

• uvicorn --version
  • Running uvicorn 0.16.0 with CPython 3.10.0 on Linux
• Run commands:
  • uvicorn bug:app --env-file .env
  • python bug.py

Additional context

No response

[Kludex]

@Kludex what do you think about this thread and this message at all?

I don’t think this is a bug. This works as intended, even if it doesn’t work with the UVICORN_ environment variables.

I guess the question now is if we want to change the behavior of env_file so uvicorn can load the environment variables with prefix UVICORN_ located on that file… And I’m not sure if it’s worth it.

[Niccolum]

I came up with solution with small changes. I’ll implement it this week, if not someone implement it faster 😃