[advanced_profiling_bug]: https://issuetracker.google.com/issues/135141615
 [japicmp]: https://github.com/siom79/japicmp
 [japicmp_gradle]: https://github.com/melix/japicmp-gradle-plugin
 [java_sams]: https://kotlinlang.org/docs/reference/java-interop.html#sam-conversions
 [kotlin_sams]: https://youtrack.jetbrains.com/issue/KT-11129
 [mockito]: https://site.mockito.org/
 [proguard_problems]: https://github.com/square/okhttp/issues/5167

```Python hl_lines="3"
import os

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

/// tip

Het tweede argument van <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> is de standaardwaarde die wordt geretourneerd.

```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.

If not provided, it's `None` by default, here we provide `"World"` as the default value to use.

Abgesehen von normalen einfachen Typen, wie `str`, `int`, `float`, usw. können Sie komplexere einfache Typen verwenden, die von `str` erben.

Um alle Optionen kennenzulernen, die Sie haben, schauen Sie sich <a href="https://docs.pydantic.dev/latest/concepts/types/" class="external-link" target="_blank">Pydantics Typübersicht</a> an. Sie werden im nächsten Kapitel ein paar Beispiele kennenlernen.

/// info

You can read more about the Starlette `lifespan` handlers in <a href="https://www.starlette.io/lifespan/" class="external-link" target="_blank">Starlette's  Lifespan' docs</a>.

Including how to handle lifespan state that can be used in other areas of your code.

///

## Sub Applications

# Controllers

Istio has a variety of [controllers](https://kubernetes.io/docs/concepts/architecture/controller/), which basically watch some inputs and do something.
This can be reading from Kubernetes and writing other objects back, writing to proxies over XDS, etc.

Unfortunately, writing controllers is very error prone, even for seemingly simple cases.
To work around this, Istio has a variety of abstractions meant to make writing controllers easier.

## Clients

[Before Upgrading](#before-upgrading).

For more information about the release and for the latest documentation,
see the [Kubernetes documentation](https://kubernetes.io/docs/home/).

[Setup topics]: https://kubernetes.io/docs/setup/pick-right-solution/
[SIGs]: https://github.com/kubernetes/community/blob/master/sig-list.md


## Major Themes

### AWS

- Removed plugin watching of the deprecated directory `{kubelet_root_dir}/plugins` and CSI V0 support in accordance with deprecation announcement in https://v1-13.docs.kubernetes.io/docs/setup/release/notes ([#84533](https://github.com/kubernetes/kubernetes/pull/84533), [@davidz627](https://github.com/davidz627))

次のようなJSONレスポンスが表示されます:

```JSON
{"message": "Hello World"}
```

### 対話的APIドキュメント

次に、<a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>にアクセスします。

自動生成された対話的APIドキュメントが表示されます (<a href="https://github.com/swagger-api/swagger-ui" class="external-link" target="_blank">Swagger UI</a>で提供):