Pydantic boolean settings cached

[lsmith77]

First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to FastAPI but to Pydantic.
• I already checked if it is not related to FastAPI but to Swagger UI.
• I already checked if it is not related to FastAPI but to ReDoc.

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• I commit to help with one of those options 👆

Example Code

class Settings(BaseSettings):
    """Load environment variables to python objects using pydantic."""

    logging_enabled: bool = False
    logging_config_filename: str = "./logs/error.log"
    logging_config_level: str = "ERROR"
    training_data_enabled: bool = False
    api_docs_username: Optional[str]
    api_docs_password: Optional[str]
    api_docs_auth_enabled: bool = False
    testing: bool = False

    class Config:
        env_file = ".env"

Description

Generally FastAPI is able to read data from the .env file but it is then somehow cached. Restarting the server does not re-read the .env values. Adding a new or renaming an setting works as expected. However, changing a value of a previously read setting has no effect. Even when removing the env_file = “.env” bit.

The issue seems to affect boolean values only. However, it does handle False vs. True properly, both via .env as well as via proper env variables.

Operating System

Linux, macOS

Operating System Details

No response

FastAPI Version

0.68.2

Python Version

3.9

Additional Context

No response

[wcastello]

I couldn't reproduce this.

I used your file as a config.py, this main.py:

from fastapi import FastAPI
from config import Settings

app = FastAPI()
settings = Settings()

@app.get("/")
async def root():
    return settings

and this .env:

API_DOCS_USERNAME="test@notsure.dev"
TESTING=false

Changing either API_DOCS_USERNAME's string or TESTING boolean on my .env works upon reloading the server. The values in these settings are updated as expected.

[lsmith77]

thank you for checking. but sorry, by now I am pretty sure its caused by VSCode and forgot to close this ticket.

microsoft/vscode-python#18203