Eles tendem a exigir configurações mais complexas, um gerenciador de fila de mensagens/tarefas, como RabbitMQ ou Redis, mas permitem que você execute tarefas em segundo plano em vários processos e, especialmente, em vários servidores.

## Caveat

If you need to perform heavy background computation and you don't necessarily need it to be run by the same process (for example, you don't need to share memory, variables, etc), you might benefit from using other bigger tools like <a href="https://docs.celeryq.dev" class="external-link" target="_blank">Celery</a>.

What happens at link time depends on whether the final binary is linked
using the internal or external mode. If other packages are compiled in
"external only" mode, then the final link will be an external one.
Otherwise the link will be an internal one.

The linking directives are used according to the kind of final link
used.

In internal mode, cmd/link itself processes all the host object files, in

* <a href="https://cdn.jsdelivr.net/npm/swagger-ui-dist@5/swagger-ui.css" class="external-link" target="_blank">`swagger-ui.css`</a>

E o **ReDoc** usa os arquivos:

* <a href="https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js" class="external-link" target="_blank">`redoc.standalone.js`</a>

  // operation, i.e. the external-attacher.
  optional bool attached = 1;

  // attachmentMetadata is populated with any
  // information returned by the attach operation, upon successful attach, that must be passed
  // into subsequent WaitForAttach or Mount calls.
  // This field must only be set by the entity completing the attach
  // operation, i.e. the external-attacher.
  // +optional

## `jsonable_encoder`の使用

JSON互換のデータのみを受信するデータベース`fase_db`があるとしましょう。

例えば、`datetime`オブジェクトはJSONと互換性がないので、このデーターベースには受け取られません。

そのため、`datetime`オブジェクトは<a href="https://en.wikipedia.org/wiki/ISO_8601" class="external-link" target="_blank">ISO形式</a>のデータを含む`str`に変換されなければなりません。

同様に、このデータベースはPydanticモデル（属性を持つオブジェクト）を受け取らず、`dict`だけを受け取ります。

そのために`jsonable_encoder`を使用することができます。

Pydanticモデルのようなオブジェクトを受け取り、JSON互換版を返します:

# 配置 Swagger UI

你可以配置一些额外的 <a href="https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/" class="external-link" target="_blank">Swagger UI 参数</a>.

如果需要配置它们，可以在创建 `FastAPI()` 应用对象时或调用 `get_swagger_ui_html()` 函数时传递 `swagger_ui_parameters` 参数。

`swagger_ui_parameters` 接受一个直接传递给 Swagger UI的字典，包含配置参数键值对。

FastAPI会将这些配置转换为 **JSON**，使其与 JavaScript 兼容，因为这是 Swagger UI 需要的。

## 不使用语法高亮

比如，你可以禁用 Swagger UI 中的语法高亮。

也就是说，**FastAPI** 针对差不多 80% 的 Python 开发者使用的编辑器进行了测试，而且其它大多数编辑器的工作方式也与之类似，因此，**FastAPI** 的优势几乎能在所有编辑器上体现。

通过这种方式，我就能找到尽可能减少代码重复的最佳方式，进而实现处处都有自动补全、类型提示与错误检查等支持。

所有这些都是为了给开发者提供最佳的开发体验。

## 需求项

经过测试多种备选方案，我最终决定使用  <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">**Pydantic**</a>，并充分利用它的优势。

  // external refers to a global metric that is not associated
  // with any Kubernetes object. It allows autoscaling based on information
  // coming from components running outside of cluster
  // (for example length of queue in cloud messaging service, or
  // QPS from loadbalancer running outside of cluster).
  // +optional
  optional ExternalMetricSource external = 5;
}

  // external refers to a global metric that is not associated
  // with any Kubernetes object. It allows autoscaling based on information
  // coming from components running outside of cluster
  // (for example length of queue in cloud messaging service, or
  // QPS from loadbalancer running outside of cluster).
  // +optional
  optional ExternalMetricSource external = 5;
}