private final Object lock = new Object();

    /*
     * Conceptually, these two variables describe the executor being in
     * one of three states:
     *   - Active: shutdown == false
     *   - Shutdown: runningTasks > 0 and shutdown == true
     *   - Terminated: runningTasks == 0 and shutdown == true
     */
    @GuardedBy("lock")

### `shutdown` event

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

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

Here, the `shutdown` event handler function will write a text line `"Application shutdown"` to a file `log.txt`.

!!! info

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!}
```

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"

👆 💪 🚮 🌅 🌘 1️⃣ 🎉 🐕‍🦺 🔢.

& 👆 🈸 🏆 🚫 ▶️ 📨 📨 ⏭ 🌐 `startup` 🎉 🐕‍🦺 ✔️ 🏁.

### `shutdown` 🎉

🚮 🔢 👈 🔜 🏃 🕐❔ 🈸 🤫 🔽, 📣 ⚫️ ⏮️ 🎉 `"shutdown"`:

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

📥, `shutdown` 🎉 🐕‍🦺 🔢 🔜 ✍ ✍ ⏸ `"Application shutdown"` 📁 `log.txt`.

!!! info
     `open()` 🔢, `mode="a"` ⛓ "🎻",, ⏸ 🔜 🚮 ⏮️ ⚫️❔ 🔛 👈 📁, 🍵 📁 ⏮️ 🎚.

### Evento `shutdown`

Para adicionar uma função que deve ser executada quando a aplicação estiver encerrando, declare ela com o evento `"shutdown"`:

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

Aqui, a função de manipulação de evento `shutdown` irá escrever uma linha de texto `"Application shutdown"` no arquivo `log.txt`.

!!! info "Informação"

			if err := httpServer.Shutdown(); err != nil && !errors.Is(err, http.ErrServerClosed) {
				shutdownLogIf(context.Background(), err)
			}
		}

		if objAPI := newObjectLayerFn(); objAPI != nil {
			shutdownLogIf(context.Background(), objAPI.Shutdown(context.Background()))
		}

		if srv := newConsoleServerFn(); srv != nil {
			shutdownLogIf(context.Background(), srv.Shutdown())
		}

    redQueue.shutdown()

    redQueue.execute("task", 100.µs) {
      // Do nothing.
    }

    taskFaker.assertNoMoreTasks()

    assertThat(testLogHandler.takeAll()).containsExactly(
      "FINE: Q10000 schedule canceled (queue is shutdown): task",
    )
  }

  @Test fun scheduleThrowsWhenShutdown() {
    redQueue.shutdown()

    ignoreIoExceptions {
      socket.close()
    }

    // Release the threads.
    writerQueue.shutdown()
    pushQueue.shutdown()
    settingsListenerQueue.shutdown()
  }

  private fun failConnection(e: IOException?) {
    close(ErrorCode.PROTOCOL_ERROR, ErrorCode.PROTOCOL_ERROR, e)
  }

  /**

    override fun execute(
      taskRunner: TaskRunner,
      runnable: Runnable,
    ) {
      executor.execute(runnable)
    }

    fun shutdown() {
      executor.shutdown()
    }
  }

  companion object {
    val logger: Logger = Logger.getLogger(TaskRunner::class.java.name)

    @JvmField

func (er erasureObjects) NewNSLock(bucket string, objects ...string) RWLocker {
	return er.nsMutex.NewNSLock(er.getLockers, bucket, objects...)
}

// Shutdown function for object storage interface.
func (er erasureObjects) Shutdown(ctx context.Context) error {
	// Add any object layer shutdown activities here.
	closeStorageDisks(er.getDisks()...)
	return nil
}

// defaultWQuorum write quorum based on setDriveCount and defaultParityCount