Параметр `lifespan` приложения `FastAPI` принимает асинхронный менеджер контекста, поэтому мы можем передать ему наш новый асинхронный менеджер контекста `lifespan`.

{* ../../docs_src/events/tutorial003_py39.py hl[22] *}

## Альтернативные события (устаревшие) { #alternative-events-deprecated }

/// warning | Предупреждение

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.

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"`:

![Events Diagram](../assets/images/events@2x.png)

Here’s a [sample event listener](https://github.com/square/okhttp/blob/master/samples/guide/src/main/java/okhttp3/recipes/PrintEventsNonConcurrent.java) that prints each event with a timestamp.

```java

	NamespaceFormat = "namespace"

	// AccessFormat - access log format used in some event targets.
	AccessFormat = "access"

	// AMZTimeFormat - event time format.
	AMZTimeFormat = "2006-01-02T15:04:05.000Z"

	// StoreExtension - file extension of an event file in store
	StoreExtension = ".event"
)

// Identity represents access key who caused the event.
type Identity struct {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.sse.internal

internal data class Event(
  val id: String?,
  val type: String?,
  val data: String,

- When `SchedulerQueueingHint` is enabled,
  the scheduler's in-tree plugins now subscribe to specific node events to decide whether to requeue Pods.
  This allows the scheduler to handle cluster events faster with less memory.

  Specific node events include updates to taints, tolerations or allocatable.

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。

import org.apache.maven.api.annotations.Nonnull;

/**
 * Event sent by maven during various phases of the build process.
 * Such events can be listened to using {@link Listener}s objects
 * registered in the {@link Session}.
 *
 * @since 4.0.0
 */
@Experimental
public interface Event {

    /**
     * Gets the type of the event.
     *
     * @return the type of the event, never {@code null}
     */
    @Nonnull