* <a href="https://github.com/JoshData/python-email-validator" target="_blank"><code>email-validator</code></a> - per la validazione di email.

Usate da Starlette:

* <a href="http://docs.python-requests.org" target="_blank"><code>requests</code></a> - Richiesto se vuoi usare il `TestClient`.
* <a href="https://github.com/Tinche/aiofiles" target="_blank"><code>aiofiles</code></a> - Richiesto se vuoi usare `FileResponse` o `StaticFiles`.

}

// LimitResponse defines how to handle requests that can not be executed right now.
// +union
message LimitResponse {
  // `type` is "Queue" or "Reject".
  // "Queue" means that requests that can not be executed upon arrival
  // are held in a queue until they can be executed or a queuing limit
  // is reached.
  // "Reject" means that requests that can not be executed upon arrival
  // are rejected.

### Request metrics

Metrics about requests served by the current node.

| Path            | Description                                   |
|-----------------|-----------------------------------------------|
| `/api/requests` | Metrics over all requests.                    |
| `/bucket/api`   | Metrics over all requests for a given bucket. |

#### `/api/requests`

requests_max                    (number)    set the maximum number of concurrent requests (default: 'auto')
cluster_deadline                (duration)  set the deadline for cluster readiness check (default: '10s')
cors_allow_origin               (csv)       set comma separated list of origins allowed for CORS requests (default: '*')

// LimitedPriorityLevelConfiguration specifies how to handle requests that are subject to limits.
// It addresses two issues:
//   - How are requests for this priority level limited?
//   - What should be done with requests that exceed the limit?
message LimitedPriorityLevelConfiguration {
  // `assuredConcurrencyShares` (ACS) configures the execution
  // limit, which is a limit on the number of requests of this

// LimitedPriorityLevelConfiguration specifies how to handle requests that are subject to limits.
// It addresses two issues:
//   - How are requests for this priority level limited?
//   - What should be done with requests that exceed the limit?
message LimitedPriorityLevelConfiguration {
  // `assuredConcurrencyShares` (ACS) configures the execution
  // limit, which is a limit on the number of requests of this

  //
  // 'object' - The object from the incoming request. The value is null for DELETE requests.
  // 'oldObject' - The existing object. The value is null for CREATE requests.
  // 'request' - Attributes of the admission request(/pkg/apis/admission/types.go#AdmissionRequest).

  /**
   * The interval between two unit requests, at our stable rate. E.g., a stable rate of 5 permits
   * per second has a stable interval of 200ms.
   */
  double stableIntervalMicros;

  /**
   * The time when the next request (no matter its size) will be granted. After granting a request,
   * this is pushed further in the future. Large requests push this further than small requests.
   */

Os status codes na faixa dos 400 significam que houve um erro por parte do cliente.

Você se lembra de todos aqueles erros (e piadas) a respeito do "**404 Not Found**"?

## Use o `HTTPException`

Para retornar ao cliente *responses* HTTP com erros, use o `HTTPException`.

### Import `HTTPException`

```Python hl_lines="1"

/// tip

Vous pouvez <a href="https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/commenting-on-a-pull-request" class="external-link" target="_blank">ajouter des commentaires avec des suggestions de changement</a> aux pull requests existantes.