app = FastAPI()


@lru_cache
def get_settings():
    return Settings()


@app.get("/info")
async def info(settings: Annotated[Settings, Depends(get_settings)]):
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    app_name: str = "Awesome API"
    admin_email: str

<resources>
  <string name="app_name">android-test</string>

Then, when you create an instance of that `Settings` class (in this case, in the `settings` object), Pydantic will read the environment variables in a case-insensitive way, so, an upper-case variable `APP_NAME` will still be read for the attribute `app_name`.

Next it will convert and validate the data. So, when you use that `settings` object, you will have data of the types you declared (e.g. `items_per_user` will be an `int`).

### Use the `settings`

from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    app_name: str = "Awesome API"
    admin_email: str

然后，它将转换和验证数据。因此，当您使用该 `settings` 对象时，您将获得您声明的类型的数据（例如 `items_per_user` 将为 `int` 类型）。

### 使用 `settings`

然后，您可以在应用程序中使用新的 `settings` 对象：

```Python hl_lines="18-20"
{!../../../docs_src/settings/tutorial001.py!}
```

### 运行服务器

接下来，您将运行服务器，并将配置作为环境变量传递。例如，您可以设置一个 `ADMIN_EMAIL` 和 `APP_NAME`，如下所示：

<div class="termy">

    from docs_src.settings.tutorial001_pv1 import app

    client = TestClient(app)
    response = client.get("/info")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "app_name": "Awesome API",
        "admin_email": "******@****.***",
        "items_per_user": 50,

<resources>
  <string name="app_name">android-test</string>

<resources>
  <string name="app_name">regression-test</string>

@needs_pydanticv2
def test_settings(monkeypatch: MonkeyPatch):
    from docs_src.settings.app02 import main

    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    settings = main.get_settings()
    assert settings.app_name == "Awesome API"
    assert settings.items_per_user == 50


@needs_pydanticv2
def test_override_settings():
    from docs_src.settings.app02 import test_main