Python 3.8+

FastAPI está sobre los hombros de gigantes:

* <a href="https://www.starlette.io/" class="external-link" target="_blank">Starlette</a> para las partes web.
* <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> para las partes de datos.

## Instalación

<div class="termy">

```console
$ pip install fastapi

---> 100%
```

</div>

  optional k8s.io.apimachinery.pkg.apis.meta.v1.LabelSelector objectSelector = 2;

  // ResourceRules describes what operations on what resources/subresources the ValidatingAdmissionPolicy matches.
  // The policy cares about an operation if it matches _any_ Rule.
  // +listType=atomic
  // +optional
  repeated NamedRuleWithOperations resourceRules = 3;

    var finished: Boolean = false,
  ) : Sink {
    /**
     * Buffer of outgoing data. This batches writes of small writes into this sink as larges frames
     * written to the outgoing connection. Batching saves the (small) framing overhead.
     */
    private val sendBuffer = Buffer()

    /** Trailers to send at the end of the stream. */

## Detalhes Técnicos

Versões modernas de Python tem suporte para **"código assíncrono"** usando algo chamado **"corrotinas"**, com sintaxe **`async` e `await`**.

Vamos ver aquela frase por partes na seção abaixo:

* **Código assíncrono**
* **`async` e `await`**
* **Corrotinas**

## Código assíncrono

// of resourceRules or nonResourceRules matches the request.
message PolicyRulesWithSubjects {
  // subjects is the list of normal user, serviceaccount, or group that this rule cares about.
  // There must be at least one member in this slice.
  // A slice that includes both the system:authenticated and system:unauthenticated user groups matches every request.
  // +listType=atomic
  // Required.

// of resourceRules or nonResourceRules matches the request.
message PolicyRulesWithSubjects {
  // subjects is the list of normal user, serviceaccount, or group that this rule cares about.
  // There must be at least one member in this slice.
  // A slice that includes both the system:authenticated and system:unauthenticated user groups matches every request.
  // +listType=atomic
  // Required.

  // the loadBalancerIP when a load balancer is created.
  // This field will be ignored if the cloud-provider does not support the feature.
  // Deprecated: This field was under-specified and its meaning varies across implementations,
  // and it cannot support dual-stack.
  // As of Kubernetes v1.24, users are encouraged to use implementation-specific annotations when available.
  // This field may be removed in a future API version.

Ele é projetado para ter funções que recebem dois parâmetros, uma "requisição" e uma "resposta". Então você "lê" as partes da requisição, e "escreve" partes para a resposta. Devido ao seu design, não é possível declarar parâmetros de requisição e corpos com _type hints_ Python padrão como parâmetros de funções.

  // ClientConfig defines how to communicate with the hook.
  // Required
  optional WebhookClientConfig clientConfig = 2;

  // Rules describes what operations on what resources/subresources the webhook cares about.
  // The webhook cares about an operation if it matches _any_ Rule.
  // However, in order to prevent ValidatingAdmissionWebhooks and MutatingAdmissionWebhooks

    ```

...and **FastAPI** will know what to do.

!!! tip
    If that seems more confusing than helpful, disregard it, you don't *need* it.