# Concurrency and async / await

Details about the `async def` syntax for *path operation functions* and some background about asynchronous code, concurrency, and parallelism.

## In a hurry?

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

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

# 동시성과 async / await

*경로 작동 함수*에서의 `async def` 문법에 대한 세부사항과 비동기 코드, 동시성 및 병렬성에 대한 배경

## 바쁘신 경우

<strong>요약</strong>

다음과 같이 `await`를 사용해 호출하는 제3의 라이브러리를 사용하는 경우:

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

다음처럼 *경로 작동 함수*를 `async def`를 사용해 선언하십시오:

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

!!! note "참고"

          fail("")
        }
      },
    )
    assertThat(server.takeRequest().sequenceNumber)
      .isEqualTo(expectedSequenceNumber)
    responseDequeuedLatch!!.await()
    call.cancel()
    requestCanceledLatch!!.countDown()
    latch.await()
  }

  @ParameterizedTest
  @ArgumentsSource(ProtocolParamProvider::class)
  fun noRecoveryFromRefusedStreamWithRetryDisabled(
    protocol: Protocol,

    }

    val startedTask = startNextTask()
    val otherTasksStarted = startedTask != yieldCompleteTask

    try {
      while (currentTask != self) {
        taskRunner.condition.await()
      }
    } finally {
      serialTaskQueue.remove(yieldCompleteTask)
    }

    // If we're yielding until we're exhausted and a task run, keep going until a task doesn't run.

{!../../../docs_src/app_testing/tutorial001.py!}
```

!!! tip "Подсказка"
    Обратите внимание, что тестирующая функция является обычной `def`, а не асинхронной `async def`.

    И вызов клиента также осуществляется без `await`.

    Это позволяет вам использовать `pytest` без лишних усложнений.

!!! note "Технические детали"
    Также можно написать `from starlette.testclient import TestClient`.

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Ya da <code>async def</code>...</summary>

Eğer kodunuzda `async` / `await` varsa, `async def` kullanalım:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Або використайте <code>async def</code>...</summary>

Якщо ваш код використовує `async` / `await`, скористайтеся `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Ou utilisez <code>async def</code> ...</summary>

Si votre code utilise `async` / `await`, utilisez `async def` :

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

If your code uses `async` / `await`, use `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>⚖️ ⚙️ <code>async def</code>...</summary>

🚥 👆 📟 ⚙️ `async` / `await`, ⚙️ `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}