Essas funções podem ser declaradas com `async def` ou `def` normal.

### Evento `startup` { #startup-event }

Para adicionar uma função que deve rodar antes de a aplicação iniciar, declare-a com o evento `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

Nesse caso, a função de manipulador do evento `startup` inicializará os itens do "banco de dados" (apenas um `dict`) com alguns valores.

Эти функции можно объявить с `async def` или обычным `def`.

### Событие `startup` { #startup-event }

Чтобы добавить функцию, которую нужно запустить до старта приложения, объявите её как обработчик события `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

Diese Funktionen können mit `async def` oder normalem `def` deklariert werden.

### `startup`-Event { #startup-event }

Um eine Funktion hinzuzufügen, die vor dem Start der Anwendung ausgeführt werden soll, deklarieren Sie diese mit dem Event `startup`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

In this case, the `startup` event handler function will initialize the items "database" (just a `dict`) with some values.

You can add more than one event handler function.

And your application won't start receiving requests until all the `startup` event handlers have completed.

### `shutdown` event { #shutdown-event }

To add a function that should be run when the application is shutting down, declare it with the event `"shutdown"`:

	UserAgent    string
}

// ToEvent - converts to notification event.
func (args eventArgs) ToEvent(escape bool) event.Event {
	eventTime := UTCNow()
	uniqueID := fmt.Sprintf("%X", eventTime.UnixNano())
	if !args.Object.ModTime.IsZero() {
		uniqueID = fmt.Sprintf("%X", args.Object.ModTime.UnixNano())
	}

	respElements := map[string]string{
		"x-amz-request-id": args.RespElements["requestId"],

首先要注意的是，我们定义了一个带有 `yield` 的异步函数。这与带有 `yield` 的依赖项非常相似。

```Python hl_lines="14-19"
{!../../docs_src/events/tutorial003.py!}
```

这个函数在 `yield`之前的部分，会在应用启动前执行。

剩下的部分在 `yield` 之后，会在应用完成后执行。

## 异步上下文管理器

如你所见，这个函数有一个装饰器 `@asynccontextmanager` 。

它将函数转化为所谓的“**异步上下文管理器**”。

```Python hl_lines="1  13"
{!../../docs_src/events/tutorial003.py!}
```

在 Python 中，  **上下文管理器**是一个你可以在 `with` 语句中使用的东西，例如，`open()` 可以作为上下文管理器使用。

    public void projectSkipped(ExecutionEvent event) {
        dispatcher.onEvent(event);
        delegate.projectSkipped(event);
    }

    @Override
    public void projectStarted(ExecutionEvent event) {
        dispatcher.onEvent(event);
        delegate.projectStarted(event);
    }

    @Override
    public void projectSucceeded(ExecutionEvent event) {
        dispatcher.onEvent(event);
        delegate.projectSucceeded(event);

  fun assertExhausted() {
    assertThat(events).isEmpty()
  }

  fun assertEvent(
    id: String?,
    type: String?,
    data: String,
  ) {
    assertThat(nextEvent()).isEqualTo(Event(id, type, data))
  }

  fun assertOpen(): EventSource {
    val event = nextEvent() as Open
    return event.eventSource
  }

  fun assertClose() {
    nextEvent() as Closed
  }

  fun assertFailure(

			// Defensive code, should never happen
			if obj.VersionID == "" {
				event.Action = NoneAction
			}
			if e.IsObjectLocked(obj) {
				event = Event{}
			}

			if e.IsPendingReplication(obj) {
				event = Event{}
			}
		}
		if !obj.IsLatest {
			switch event.Action {
			case DeleteVersionAction:
				// this noncurrent version will be expired, nothing to add
			default:

Estas funciones pueden ser declaradas con `async def` o `def` normal.

### Evento `startup` { #startup-event }

Para añadir una función que debería ejecutarse antes de que la aplicación inicie, declárala con el evento `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

En este caso, la función manejadora del evento `startup` inicializará los ítems de la "base de datos" (solo un `dict`) con algunos valores.