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!}
```

此处，`shutdown` 事件处理器函数在 `log.txt` 中写入一行文本 `Application shutdown`。

/// info | "说明"

`open()` 函数中，`mode="a"` 指的是**追加**。因此这行文本会添加在文件已有内容之后，不会覆盖之前的内容。

///

/// tip | "提示"

注意，本例使用 Python `open()` 标准函数与文件交互。

	"istio.io/istio/istioctl/pkg/ztunnelconfig"
	"istio.io/istio/operator/cmd/mesh"
	"istio.io/istio/pkg/cmd"
	"istio.io/istio/pkg/collateral"
	"istio.io/istio/pkg/config/constants"
	"istio.io/istio/pkg/log"
	"istio.io/istio/tools/bug-report/pkg/bugreport"
)

const (
	// Location to read istioctl defaults from
	defaultIstioctlConfig = "$HOME/.istioctl/config.yaml"
)

const (
	FlagCharts = "charts"
)

/**
 * @author mbechler
 *
 */
@SuppressWarnings ( {
    "javadoc", "restriction"
} )
@RunWith ( Parameterized.class )
public class KerberosTest extends BaseCIFSTest {

    private static final Logger log = LoggerFactory.getLogger(KerberosTest.class);


    /**
     * @param properties
     */
    public KerberosTest ( String name, Map<String, String> properties ) {
        super(name, properties);
    }

  // The UID is meant to track the round trip (request/response) between the KAS and the WebHook, not the user request.
  // It is suitable for correlating log entries between the webhook and apiserver, for either auditing or debugging.
  optional string uid = 1;

  // Kind is the fully-qualified type of object being submitted (for example, v1.Pod or autoscaling.v1.Scale)

  // The UID is meant to track the round trip (request/response) between the KAS and the WebHook, not the user request.
  // It is suitable for correlating log entries between the webhook and apiserver, for either auditing or debugging.
  optional string uid = 1;

  // Kind is the fully-qualified type of object being submitted (for example, v1.Pod or autoscaling.v1.Scale)

	locked = lrwm.GetLock(ctx, "", "", duration)
	if locked {
		// fmt.Println("Write lock acquired, waiting...")
		time.Sleep(1 * time.Second)

		lrwm.Unlock()
	} else {
		t.Log("Write lock failed due to timeout")
	}
	return
}

func TestSimpleWriteLockAcquired(t *testing.T) {
	locked := testSimpleWriteLock(t, 5*time.Second)

	expected := true
	if locked != expected {

Server: nginx/1.4.6 (Ubuntu)
Content-Type: text/plain
Content-Length: 1759
Connection: keep-alive
```

We can see that we were redirected because `response.request().url()` is different from `request.url()`. The two log statements log two different URLs.

### Network Interceptors

Registering a network interceptor is quite similar. Call `addNetworkInterceptor()` instead of `addInterceptor()`:

```java

<div class="wrapper">
    <jsp:include page="/WEB-INF/view/common/admin/header.jsp"></jsp:include>
    <jsp:include page="/WEB-INF/view/common/admin/sidebar.jsp">
        <jsp:param name="menuCategoryType" value="log"/>
        <jsp:param name="menuType" value="backup"/>
    </jsp:include>
    <div class="content-wrapper">
        <div class="content-header">
            <div class="container-fluid">

	if err != nil {
		t.Fatal(err)
	}
	if got.root() == nil {
		t.Log("cached folders:")
		for folder := range got.Cache {
			t.Log("folder:", folder)
		}
		t.Fatal("got nil root.")
	}

	// Test dirs
	want := []struct {
		path       string
		isNil      bool
		size, objs int

        for (Map<String, Object> elem : jobLogList) {
            deleteMethod("/api/admin/joblog/log/" + elem.get("id"));
        }

        final List<Map<String, Object>> crawlingInfoList = readCrawlingInfo(fileConfigId);
        for (Map<String, Object> elem : crawlingInfoList) {
            deleteMethod("/api/admin/crawlinginfo/log/" + elem.get("id"));
        }