- deployment/docker.md
  - How To - Recipes:
    - how-to/index.md
    - how-to/general.md
    - how-to/graphql.md
    - how-to/custom-request-and-route.md
    - how-to/conditional-openapi.md
    - how-to/extending-openapi.md
    - how-to/separate-openapi-schemas.md
    - how-to/custom-docs-ui-assets.md
    - how-to/configure-swagger-ui.md
    - how-to/sql-databases-peewee.md

I'll also show you the **official Docker image** that includes **Gunicorn with Uvicorn workers** and some default configurations that can be useful for simple cases.

So, what we will do next is add the code to document how that *external API* should look like to receive the callback from *your API*.

That documentation will show up in the Swagger UI at `/docs` in your API, and it will let external developers know how to build the *external API*.

    //
    // p1 inherits from p0
    // p0 inherits from super model
    //
    // or we can show it graphically as:
    //
    // p1 ---> p0 --> super model
    //
    // ----------------------------------------------------------------------

    /**
     * How the test project is set up:
     *
     * 1. dependencyManagement lists dependencies on a & b,
     *    with an exclusion on c in b.

```Python hl_lines="1  7-13  19"
{!../../../docs_src/dataclasses/tutorial002.py!}
```

The dataclass will be automatically converted to a Pydantic dataclass.

This way, its schema will show up in the API docs user interface:

<img src="/img/tutorial/dataclasses/image01.png">

## Dataclasses in Nested Data Structures

It won't show up in the documentation, but other tools (such as Sphinx) will be able to use the rest.

```Python hl_lines="19-29"
{!../../../docs_src/path_operation_advanced_configuration/tutorial004.py!}
```

## Additional Responses

You probably have seen how to declare the `response_model` and `status_code` for a *path operation*.

## Lifespan

You can define this *startup* and *shutdown* logic using the `lifespan` parameter of the `FastAPI` app, and a "context manager" (I'll show you what that is in a second).

Let's start with an example and then see it in detail.

We create an async function `lifespan()` with `yield` like this:

```Python hl_lines="16  19"

### Download and Install/Run

Fess 14.12 is now available and can be downloaded on the [Releases page](https://github.com/codelibs/fess/releases "download"). Downloads come in 3 flavors: deb, rpm, zip.

The following commands show how to use the zip download:

    $ unzip fess-14.12.x.zip
    $ cd fess-14.12.x
    $ ./bin/fess

For more details, see the [Installation Guide](https://fess.codelibs.org/14.12/install/index.html).

### Docker

# Exceptions - `HTTPException` and `WebSocketException`

These are the exceptions that you can raise to show errors to the client.

When you raise an exception, as would happen with normal Python, the rest of the execution is aborted. This way you can raise these exceptions from anywhere in the code to abort a request and show the error to the client.

You can use:

* `HTTPException`
* `WebSocketException`

  fun setPolicy(
    address: Address,
    policy: AddressPolicy,
  ) {
    delegate.setPolicy(address, policy)
  }

  /**
   * A policy for how the pool should treat a specific address.
   */
  class AddressPolicy(
    /**
     * How many concurrent calls should be possible to make at any time.
     * The pool will routinely try to pre-emptively open connections to satisfy this minimum.