```console
$ gunicorn main:app --workers 4 --worker-class uvicorn.workers.UvicornWorker --bind 0.0.0.0:80

[19499] [INFO] Starting gunicorn 20.1.0
[19499] [INFO] Listening at: http://0.0.0.0:80 (19499)
[19499] [INFO] Using worker: uvicorn.workers.UvicornWorker
[19511] [INFO] Booting worker with pid: 19511
[19513] [INFO] Booting worker with pid: 19513
[19514] [INFO] Booting worker with pid: 19514
[19515] [INFO] Booting worker with pid: 19515

```console
$ pip install "hypercorn[trio]"
---> 100%
```

</div>

### Run with Trio

Then you can pass the command line option `--worker-class` with the value `trio`:

<div class="termy">

```console
$ hypercorn main:app --worker-class trio
```

</div>

And that will start Hypercorn with your app using Trio as the backend.

しかし、多くの場合、複数のワーカー・プロセスを同時に実行したいと考えるでしょう。

### 複数のプロセス - Worker

クライアントの数が単一のプロセスで処理できる数を超えており（たとえば仮想マシンがそれほど大きくない場合）、かつサーバーの CPU に**複数のコア**がある場合、同じアプリケーションで同時に**複数のプロセス**を実行させ、すべてのリクエストを分散させることができます。

同じAPIプログラムの**複数のプロセス**を実行する場合、それらは一般的に**Worker／ワーカー**と呼ばれます。

### ワーカー・プロセス と ポート
<!-- NOTE: https.md written in Japanese does not exist, so it redirects to English one  -->

[[tool.mypy.overrides]]
module = "docs_src.*"
disallow_incomplete_defs = false
disallow_untyped_defs = false
disallow_untyped_calls = false

[tool.pytest.ini_options]
addopts = [
  "--strict-config",
  "--strict-markers",
  "--ignore=docs_src",
]
xfail_strict = true
junit_family = "xunit2"
filterwarnings = [
    "error",
    # TODO: needed by asyncio in Python 3.9.7 https://bugs.python.org/issue45097, try to remove on 3.9.8

The end result is that the item paths are now:

* `/items/`
* `/items/{item_id}`

...as we intended.

* They will be marked with a list of tags that contain a single string `"items"`.
    * These "tags" are especially useful for the automatic interactive documentation systems (using OpenAPI).
* All of them will include the predefined `responses`.

* Fix typos and update wording in deployment docs. PR [#700](https://github.com/tiangolo/fastapi/pull/700) by [@marier-nico](https://github.com/tiangolo/fastapi/pull/700).
* Add note about dependencies in `APIRouter` docs. PR [#698](https://github.com/tiangolo/fastapi/pull/698) by [@marier-nico](https://github.com/marier-nico).

<a href="https://databento.com/" target="_blank" title="Pay as you go for market data"><img src="https://fastapi.tiangolo.com/img/sponsors/databento.svg"></a>

!!! note
    Notice that the input model is still validated.

    So, if you want to receive partial updates that can omit all the attributes, you need to have a model with all the attributes marked as optional (with default values or `None`).