# 并发 async / await

有关路径操作函数的 `async def` 语法以及异步代码、并发和并行的一些背景知识。

## 赶时间吗？

<abbr title="too long; didn't read(长文警告)"><strong>TL;DR:</strong></abbr>

如果你正在使用第三方库，它们会告诉你使用 `await` 关键字来调用它们，就像这样：

```Python
results = await some_library()
```

然后，通过 `async def` 声明你的 *路径操作函数*：

```Python hl_lines="2"
@app.get('/')
async def read_results():
    results = await some_library()
    return results
```

!!! note

# 並行処理と async / await

*path operation 関数*のための `async def` に関する詳細と非同期 (asynchronous) コード、並行処理 (Concurrency)、そして、並列処理 (Parallelism) の背景について。

## 急いでいますか？

<abbr title="too long; didn't read (長すぎて読めない人のための要約という意味のスラング)"><strong>TL;DR:</strong></abbr>

次のような、`await` を使用して呼び出すべきサードパーティライブラリを使用している場合:

```Python
results = await some_library()
```

以下の様に `async def` を使用して*path operation 関数*を宣言します。

```Python hl_lines="2"
@app.get('/')

        elif is_gen_callable(call) or is_async_gen_callable(call):
            solved = await solve_generator(
                call=call, stack=async_exit_stack, sub_values=sub_values
            )
        elif is_coroutine_callable(call):
            solved = await call(**sub_values)
        else:
            solved = await run_in_threadpool(call, **sub_values)
        if sub_dependant.name is not None:

* `seek(versatz)`: Geht zur Position `versatz` (`int`) in der Datei.
    * Z. B. würde `await myfile.seek(0)` zum Anfang der Datei gehen.
    * Das ist besonders dann nützlich, wenn Sie `await myfile.read()` einmal ausführen und dann diese Inhalte erneut auslesen müssen.
* `close()`: Schließt die Datei.

Da alle diese Methoden `async`hron sind, müssen Sie sie `await`en („erwarten“).

* `seek(offset)`: Перейти к байту на позиции `offset` (`int`) в файле.
    * Наример, `await myfile.seek(0)` перейдет к началу файла.
    * Это особенно удобно, если вы один раз выполнили команду `await myfile.read()`, а затем вам нужно прочитать содержимое файла еще раз.
* `close()`: Закрыть файл.

Поскольку все эти методы являются `async` методами, вам следует использовать "await" вместе с ними.

      awaitPingsSent++
    }

    // 0x4f 0x4b 0x6f 0x6b is "OKok".
    writePing(false, AWAIT_PING, 0x4f4b6f6b)
  }

  /** For testing: awaits a pong. */
  @Throws(InterruptedException::class)
  fun awaitPong() {
    this.withLock {
      while (awaitPongsReceived < awaitPingsSent) {
        condition.await()
      }
    }
  }

  @Throws(IOException::class)
  fun flush() {

* `seek(offset)`: Goes to the byte position `offset` (`int`) in the file.
    * E.g., `await myfile.seek(0)` would go to the start of the file.
    * This is especially useful if you run `await myfile.read()` once and then need to read the contents again.
* `close()`: Closes the file.

As all these methods are `async` methods, you need to "await" them.

For example, inside of an `async` *path operation function* you can get the contents with:

	writesPerSec   MetricName = "writes_per_sec"
	readsKBPerSec  MetricName = "reads_kb_per_sec"
	writesKBPerSec MetricName = "writes_kb_per_sec"
	readsAwait     MetricName = "reads_await"
	writesAwait    MetricName = "writes_await"
	percUtil       MetricName = "perc_util"
	usedInodes     MetricName = "used_inodes"

	// network stats
	interfaceRxBytes  MetricName = "rx_bytes"
	interfaceRxErrors MetricName = "rx_errors"

          ) {
            processResponse(response, hostname, responses, failures)
            latch.countDown()
          }
        },
      )
    }

    try {
      latch.await()
    } catch (e: InterruptedException) {
      failures.add(e)
    }
  }

  private fun processResponse(
    response: Response,
    hostname: String,
    results: MutableList<InetAddress>,

    // Cause acceptConnections() to break out.
    serverSocket.close()

    // Await shutdown.
    for (queue in taskRunner.activeQueues()) {
      if (!queue.idleLatch().await(5, TimeUnit.SECONDS)) {
        throw IOException("Gave up waiting for queue to shut down")
      }
    }
    taskRunnerBackend.shutdown()
  }