But before that, handling asynchronous code was quite more complex and difficult.

In previous versions of Python, you could have used threads or <a href="https://www.gevent.org/" class="external-link" target="_blank">Gevent</a>. But the code is way more complex to understand, debug, and think about.

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] *}

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!}
```

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

### Evento `startup`

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

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

Nesse caso, a função de manipulação de evento `startup` irá inicializar os itens do "banco de dados" (só um `dict`) com alguns valores.

# 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!}

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!}
```

        dispatcher.onEvent(event);
        delegate.artifactInstalling(event);
    }

    @Override
    public void artifactResolved(RepositoryEvent event) {
        dispatcher.onEvent(event);
        delegate.artifactResolved(event);
    }

    @Override
    public void artifactResolving(RepositoryEvent event) {
        dispatcher.onEvent(event);
        delegate.artifactResolving(event);
    }

    @Override

    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);

# Events testen: Hochfahren – Herunterfahren

Wenn Sie in Ihren Tests Ihre Event-Handler (`startup` und `shutdown`) ausführen wollen, können Sie den `TestClient` mit einer `with`-Anweisung verwenden:

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

	"github.com/minio/minio/internal/config/subnet"
	xhttp "github.com/minio/minio/internal/http"
	etcd "go.etcd.io/etcd/client/v3"

	levent "github.com/minio/minio/internal/config/lambda/event"
	"github.com/minio/minio/internal/event"
	"github.com/minio/minio/internal/pubsub"
	"github.com/minio/pkg/v3/certs"
	"github.com/minio/pkg/v3/env"
	xnet "github.com/minio/pkg/v3/net"
)