*
         * @param source    the source value
         * @param fieldName a description of the field being interpolated. The implementation may use this to
         *                  log stuff
         * @return the interpolated value
         */
        String transform(String source, String fieldName);
    }

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。

			b.Fatal(err)
		}
	}
}

func TestEncodeDecodehealingTracker(t *testing.T) {
	v := healingTracker{}
	var buf bytes.Buffer
	msgp.Encode(&buf, &v)

	m := v.Msgsize()
	if buf.Len() > m {
		t.Log("WARNING: TestEncodeDecodehealingTracker Msgsize() is inaccurate")
	}

	vn := healingTracker{}
	err := msgp.Decode(&buf, &vn)
	if err != nil {
		t.Error(err)
	}

	buf.Reset()
	msgp.Encode(&buf, &v)

						foundLocal = true
					}
					continue
				}

				// Log the message to console about the host resolving
				reqInfo := (&logger.ReqInfo{}).AppendTags(
					"host",
					endpoints[i].Hostname(),
				)

				if orchestrated && hostResolveToLocalhost(endpoints[i]) {
					// time elapsed
					timeElapsed := time.Since(startTime)
					// log error only if more than a second has elapsed

	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 {

      if (files != null) {
        for (File f : files) {
          if (!delete(f)) {
            return false;
          }
        }
      }
    }

    if (!file.delete()) {
      logger.log(Level.WARNING, "couldn't delete file: {0}", new Object[] {file});
      return false;
    }

    return true;
  }

        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"));
        }

	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

* Audit policy supports matching subresources and resource names, but the top level resource no longer matches the subresouce. For example "pods" no longer matches requests to the logs subresource of pods. Use "pods/logs" to match subresources. ([#48836](https://github.com/kubernetes/kubernetes/pull/48836), [@ericchiang](https://github.com/ericchiang))

    // This is an extremely fast implementation of BigInteger.doubleValue(). JDK patch pending.
    BigInteger absX = x.abs();
    int exponent = absX.bitLength() - 1;
    // exponent == floor(log2(abs(x)))
    if (exponent < Long.SIZE - 1) {
      return x.longValue();
    } else if (exponent > MAX_EXPONENT) {
      return x.signum() * POSITIVE_INFINITY;
    }

    /*