import os
from typing import Any, Dict, List

from pdm.backend.hooks import Context

TIANGOLO_BUILD_PACKAGE = os.getenv("TIANGOLO_BUILD_PACKAGE", "fastapi")


def pdm_build_initialize(context: Context) -> None:
    metadata = context.config.metadata
    # Get custom config for the current package, from the env var
    config: Dict[str, Any] = context.config.data["tool"]["tiangolo"][
        "_internal-slim-build"

🖼 👆 💪 ✔️ 📁 `main.py` ⏮️:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

!!! tip
    🥈 ❌ <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> 🔢 💲 📨.

    🚥 🚫 🚚, ⚫️ `None` 🔢, 📥 👥 🚚 `"World"` 🔢 💲 ⚙️.

⤴️ 👆 💪 🤙 👈 🐍 📋:

Sie könnten zum Beispiel eine Datei `main.py` haben mit:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

!!! tip "Tipp"
    Das zweite Argument für <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> ist der zurückzugebende Defaultwert.

For example you could have a file `main.py` with:

```Python hl_lines="3"
import os

name = os.getenv("MY_NAME", "World")
print(f"Hello {name} from Python")
```

!!! tip
    The second argument to <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> is the default value to return.

这种做法相当常见，有一个名称，这些环境变量通常放在一个名为 `.env` 的文件中，该文件被称为“dotenv”。

!!! tip
    以点 (`.`) 开头的文件是 Unix-like 系统（如 Linux 和 macOS）中的隐藏文件。

    但是，dotenv 文件实际上不一定要具有确切的文件名。

Pydantic 支持使用外部库从这些类型的文件中读取。您可以在<a href="https://docs.pydantic.dev/latest/concepts/pydantic_settings/#dotenv-env-support" class="external-link" target="_blank">Pydantic 设置: Dotenv (.env) 支持</a>中阅读更多相关信息。

!!! tip

from pytest import MonkeyPatch

from ...utils import needs_pydanticv2


@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 fastapi.testclient import TestClient
from pytest import MonkeyPatch

from ...utils import needs_pydanticv2


@needs_pydanticv2
def test_settings(monkeypatch: MonkeyPatch):
    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    from docs_src.settings.tutorial001 import app

    client = TestClient(app)
    response = client.get("/info")
    assert response.status_code == 200, response.text
    assert response.json() == {

* 🔥 Remove unnecessary duplicated docstrings. PR [#10484](https://github.com/tiangolo/fastapi/pull/10484) by [@tiangolo](https://github.com/tiangolo).

### Internal

* ✏️ Update Pydantic links to dotenv support. PR [#10511](https://github.com/tiangolo/fastapi/pull/10511) by [@White-Mask](https://github.com/White-Mask).

Und Sie könnten eine einzelne Abhängigkeit haben, die auf mehreren ge`yield`eten Abhängigkeiten basiert, usw.

Sie können beliebige Kombinationen von Abhängigkeiten haben.

**FastAPI** stellt sicher, dass alles in der richtigen Reihenfolge ausgeführt wird.

!!! note "Technische Details"

from fastapi.testclient import TestClient
from pytest import MonkeyPatch

from ...utils import needs_pydanticv1


@needs_pydanticv1
def test_settings(monkeypatch: MonkeyPatch):
    monkeypatch.setenv("ADMIN_EMAIL", "******@****.***")
    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() == {