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

### `startup`-Event

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

```Python hl_lines="8"
{!../../docs_src/events/tutorial001.py!}
```

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

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

{* ../../docs_src/events/tutorial002.py hl[6] *}

# Testing Events: startup - shutdown

When you need your event handlers (`startup` and `shutdown`) to run in your tests, you can use the `TestClient` with a `with` statement:

```Python hl_lines="9-12  20-24"
{!../../docs_src/app_testing/tutorial003.py!}

![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 {

使用 `startup` 事件声明 `app` 启动前运行的函数：

```Python hl_lines="8"
{!../../docs_src/events/tutorial001.py!}
```

本例中，`startup` 事件处理器函数为项目数据库（只是**字典**）提供了一些初始值。

**FastAPI** 支持多个事件处理器函数。

只有所有 `startup` 事件处理器运行完毕，**FastAPI** 应用才开始接收请求。

## `shutdown` 事件

使用 `shutdown` 事件声明 `app` 关闭时运行的函数：

```Python hl_lines="6"
{!../../docs_src/events/tutorial002.py!}
```

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

type GetObjectContext struct {
	OutputRoute string `json:"outputRoute"`
	OutputToken string `json:"outputToken"`
	InputS3URL  string `json:"inputS3Url"`
}

// Event represents lambda function event, this is undocumented in AWS S3. This
// structure bases itself on this structure but there is no binding.
//
//	{
//	  "xAmzRequestId": "a2871150-1df5-4dc9-ad9f-3da283ca1bf3",
//	  "getObjectContext": {
//	    "outputRoute": "...",

 * 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,

	"github.com/minio/minio/internal/event"
	xhttp "github.com/minio/minio/internal/http"
	"github.com/minio/minio/internal/pubsub"
	"github.com/minio/pkg/v3/policy"
)

// EventNotifier - notifies external systems about events in MinIO.
type EventNotifier struct {
	sync.RWMutex
	targetList     *event.TargetList
	bucketRulesMap map[string]event.RulesMap
}