# 並行処理と async / await { #concurrency-and-async-await }

*path operation 関数*のための `async def` 構文に関する詳細と、非同期コード、並行処理、並列処理の背景についてです。

## 急いでいますか？ { #in-a-hurry }

<abbr title="too long; didn't read - 長すぎて読まなかった"><strong>TL;DR:</strong></abbr>

次のように `await` で呼び出すよう指示されているサードパーティライブラリを使っているなら:

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

*path operation 関数*は次のように `async def` で宣言します:

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

      - master
  pull_request:
    types: [opened, labeled, unlabeled, synchronize]

permissions:
  contents: read

env:
  GRADLE_OPTS: "-Xmx4g -Dorg.gradle.daemon=false -Dkotlin.incremental=false"

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  publish:
    runs-on: ubuntu-latest
    if: github.repository == 'square/okhttp' && github.ref == 'refs/heads/master'

                final long seqNo = getLongValue(result, "_seq_no");
                final long primaryTerm = getLongValue(result, "_primary_term");

                // Try to delete with optimistic concurrency
                try (CurlResponse deleteResponse = ComponentUtil.getCurlHelper() //
                        .delete("/" + getIndexName() + "/_doc/" + operationName //

            assertTrue(exception.getMessage().contains("Signature verification failed"));
        }
    }

    @Nested
    @DisplayName("Concurrency Tests")
    class ConcurrencyTests {

        @Test
        @DisplayName("Should handle concurrent received notifications")
        void testConcurrentReceived() throws InterruptedException {

import java.util.Collections;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.Executor;
import java.util.logging.Level;

/**
 * A list of listeners for implementing a concurrency friendly observable object.
 *
 * <p>Listeners are registered once via {@link #addListener} and then may be invoked by {@linkplain
 * #enqueue enqueueing} and then {@linkplain #dispatch dispatching} events.
 *

import inspect
import sys
from collections.abc import AsyncGenerator, Generator
from functools import wraps

import pytest
from fastapi import Depends, FastAPI
from fastapi.concurrency import iterate_in_threadpool, run_in_threadpool
from fastapi.testclient import TestClient

if sys.version_info >= (3, 13):  # pragma: no cover
    from inspect import iscoroutinefunction
else:  # pragma: no cover
    from asyncio import iscoroutinefunction

    is_uploadfile_sequence_annotation,
    lenient_issubclass,
    sequence_types,
    serialize_sequence_value,
    value_is_sequence,
)
from fastapi.background import BackgroundTasks
from fastapi.concurrency import (
    asynccontextmanager,
    contextmanager_in_threadpool,
)
from fastapi.dependencies.models import Dependant
from fastapi.exceptions import DependencyScopeError
from fastapi.logger import logger

* the `Authorization` header
* the forwarded header

* the dependency injection system
* the dependency
* the dependable
* the dependant

* I/O bound
* CPU bound
* concurrency
* parallelism
* multiprocessing

* the env var
* the environment variable
* the `PATH`
* the `PATH` variable

* the authentication
* the authentication provider
* the authorization

* o cabeçalho `Authorization`
* o cabeçalho encaminhado

* o sistema de injeção de dependências
* a dependência
* o dependable
* o dependant

* limitado por I/O
* limitado por CPU
* concorrência
* paralelismo
* multiprocessamento

* a env var
* a variável de ambiente
* o `PATH`
* a variável `PATH`

* a autenticação
* o provedor de autenticação
* a autorização

En ajoutant `standard`, Uvicorn va installer et utiliser quelques dépendances supplémentaires recommandées.

Cela inclut `uvloop`, le remplaçant hautes performances de `asyncio`, qui fournit le gros gain de performance en matière de concurrence.

Lorsque vous installez FastAPI avec quelque chose comme `pip install "fastapi[standard]"`, vous obtenez déjà `uvicorn[standard]` aussi.

///

## Exécuter le programme serveur { #run-the-server-program }