* that exhibits the problem.
 *
 */
public interface Problem {

    /**
     * The different severity levels for a problem, in decreasing order.
     */
    enum Severity {
        FATAL, //
        ERROR, //
        WARNING //
    }

    /**
     * Gets the hint about the source of the problem. While the syntax of this hint is unspecified and depends on the

                        c = interpolator.interpolate(value, recursionInterceptor);
                    } catch (InterpolationException e) {
                        problems.add(new ModelProblemCollectorRequest(Severity.ERROR, Version.BASE)
                                .setMessage(e.getMessage())
                                .setException(e));
                    }
                    cache.put(value, c);
                }

    Kubernetes-managed containers on the node.
  * It is not compatible with CNI plugins that do not conform to the
    [error handling behavior in the spec](https://github.com/containernetworking/cni/blob/master/SPEC.md#network-configuration-list-error-handling).
    The plugins are being updated to resolve this issue ([#43488](https://github.com/kubernetes/kubernetes/issues/43488)).

	}

	for i, testCase := range testCases {
		config.SetRegion(globalServerConfig, testCase.serverConfigRegion)
		_, actualCode := parseLocationConstraint(testCase.request)
		if testCase.expectedCode != actualCode {
			t.Errorf("Test %d: Expected the APIErrCode to be %d, but instead found %d", i+1, testCase.expectedCode, actualCode)
		}
	}
}

// Tests validate metadata extraction from http headers.
func TestExtractMetadataHeaders(t *testing.T) {

	close(workers[0])
	wg.Wait()
	for _, obj := range expired {
		switch obj.ObjectV.VersionID {
		case uuids[2].String(), uuids[3].String(), uuids[4].String():
		default:
			t.Errorf("Unexpected versionID being expired: %#v\n", obj)
		}
	}
}

func TestEvalActionFromLifecycle(t *testing.T) {
	// Tests cover only ExpiredObjectDeleteAllVersions and DelMarkerExpiration actions

  /** True if there was an exception on the connection to the peer. */
  internal var hasFailure: Boolean = false
    private set

  internal val connection: RealConnection
    get() = codec.carrier as? RealConnection ?: error("no connection for CONNECT tunnels")

  internal val isCoalescedConnection: Boolean
    get() = finder.routePlanner.address.url.host != codec.carrier.route.address.url.host

  @Throws(IOException::class)

{!> ../../docs_src/security/tutorial007.py!}
```

////

这类似于：

```Python
if not (credentials.username == "stanleyjobson") or not (credentials.password == "swordfish"):
    # Return some error
    ...
```

但使用 `secrets.compare_digest()`，可以防御**时差攻击**，更加安全。

### 时差攻击

什么是**时差攻击**？

假设攻击者试图猜出用户名与密码。

他们发送用户名为 `johndoe`，密码为 `love123`  的请求。

然后，Python 代码执行如下操作：

# This should only be necessary when running on A GCP VM, on a default
# network, which has the MTU of 1460,
# due to 40 bytes being reserved for GCP's internal usage.
# Note, an invalid sub-interface name will lead to an obscure error, e.g.:
# "The filename, directory name, or volume label syntax is incorrect."
# In such cases, check that the name of the sub-interface is valid:
# `netsh interface show interface`

        try {
            updateRepositoryMetadata(localRepository, remoteRepository);
        } catch (IOException | XMLStreamException e) {
            throw new RepositoryMetadataStoreException("Error updating group repository metadata", e);
        }
    }

    protected void updateRepositoryMetadata(ArtifactRepository localRepository, ArtifactRepository remoteRepository)

	hstats.totalS3Requests.Inc(api)
	code := w.StatusCode

	switch {
	case code == 0:
	case code == 499:
		// 499 is a good error, shall be counted as canceled.
		hstats.totalS3Canceled.Inc(api)
	case code >= http.StatusBadRequest:
		if code >= http.StatusInternalServerError {
			hstats.totalS35xxErrors.Inc(api)
		} else {