# Concorrência e async / await { #concurrency-and-async-await }

Detalhes sobre a sintaxe `async def` para *funções de operação de rota* e alguns conceitos de código assíncrono, concorrência e paralelismo.

## Com pressa? { #in-a-hurry }

<abbr title="too long; didn't read - muito longo; não li"><strong>TL;DR:</strong></abbr>

Se você estiver utilizando bibliotecas de terceiros que dizem para você chamar as funções com `await`, como:

```Python

async def stream_raw() -> AsyncIterable[str]:
    """Async generator with no internal await - would hang without checkpoint."""
    i = 0
    while True:
        yield f"item {i}\n"
        i += 1


@app.get("/stream-jsonl")
async def stream_jsonl() -> AsyncIterable[int]:
    """JSONL async generator with no internal await."""
    i = 0
    while True:
        yield i
        i += 1

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            try:
                return await original_route_handler(request)
            except RequestValidationError as exc:
                body = await request.body()
                detail = {"errors": exc.errors(), "body": body.decode()}
                raise HTTPException(status_code=422, detail=detail)

    assertFalse(service.startUpCalled);

    service.startAsync().awaitRunning();
    assertTrue(service.startUpCalled);
    assertEquals(Service.State.RUNNING, service.state());

    enterRun.await(); // to avoid stopping the service until run() is invoked

    service.stopAsync().awaitTerminated();
    assertTrue(service.shutDownCalled);
    assertEquals(Service.State.TERMINATED, service.state());

            ready.countDown()
            try {
              proceed.await(5, TimeUnit.SECONDS)
            } catch (e: InterruptedException) {
              throw RuntimeException(e)
            }
            chain.proceed(chain.request())
          },
        ).build()
    val t1 = makeSynchronousCall(client.newCall(newRequest("http://a/3")))
    ready.await(5, TimeUnit.SECONDS)
    executor.finishJob("http://a/2")

///

次に、アプリを渡して `AsyncClient` を作成し、`await` を使って非同期リクエストを送信できます。

{* ../../docs_src/async_tests/app_a_py310/test_main.py hl[9:12] *}

これは次と同等です:

```Python
response = client.get('/')
```

...これまでは `TestClient` でリクエストを送っていました。

/// tip | 豆知識

新しい `AsyncClient` では async/await を使っている点に注意してください。リクエストは非同期です。

///

/// warning | 注意

    exit_limiter = CapacityLimiter(1)
    try:
        yield await run_in_threadpool(cm.__enter__)
    except Exception as e:
        ok = bool(
            await anyio.to_thread.run_sync(
                cm.__exit__, type(e), e, e.__traceback__, limiter=exit_limiter
            )
        )
        if not ok:
            raise e
    else:
        await anyio.to_thread.run_sync(

        for (int t = 0; t < numThreads; t++) {
            final int threadId = t;
            executor.submit(() -> {
                try {
                    startLatch.await();
                    for (int i = 0; i < eventsPerThread; i++) {
                        helper.offer(new LogNotificationEvent(i, "ERROR", "org.test", "t" + threadId + "-" + i, null));

@GwtIncompatible
abstract class ForwardingCondition implements Condition {
  abstract Condition delegate();

  @Override
  public void await() throws InterruptedException {
    delegate().await();
  }

  @Override
  public boolean await(long time, TimeUnit unit) throws InterruptedException {
    return delegate().await(time, unit);
  }

  @Override
  public void awaitUninterruptibly() {
    delegate().awaitUninterruptibly();
  }

# Concurrence et async / await { #concurrency-and-async-await }

Détails sur la syntaxe `async def` pour les *fonctions de chemin d'accès* et quelques rappels sur le code asynchrone, la concurrence et le parallélisme.

## Vous êtes pressés ? { #in-a-hurry }

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

Si vous utilisez des bibliothèques tierces qui nécessitent d'être appelées avec `await`, telles que :

```Python