// ErrSubQueryRequired sub query required
	ErrSubQueryRequired = errors.New("sub query required")
	// ErrInvalidData unsupported data
	ErrInvalidData = errors.New("unsupported data")
	// ErrUnsupportedDriver unsupported driver
	ErrUnsupportedDriver = errors.New("unsupported driver")
	// ErrRegistered registered
	ErrRegistered = errors.New("registered")

package cmd

import (
	"errors"
)

// errInvalidArgument means that input argument is invalid.
var errInvalidArgument = errors.New("Invalid arguments specified")

// errMethodNotAllowed means that method is not allowed.
var errMethodNotAllowed = errors.New("Method not allowed")

// errSignatureMismatch means signature did not match.
var errSignatureMismatch = errors.New("Signature does not match")

var errDoneForNow = errors.New("done for now")

// errSkipFile returned by the fn() for readDirFn() when it needs
// to proceed to next entry.
var errSkipFile = errors.New("skip this file")

var errIgnoreFileContrib = errors.New("ignore this file's contribution toward data-usage")

// errXLBackend XL drive mode requires fresh deployment.
var errXLBackend = errors.New("XL backend requires fresh drive")

}

// toAPIErrorCode - Converts embedded errors. Convenience
// function written to handle all cases where we have known types of
// errors returned by underlying layers.
func toAPIErrorCode(ctx context.Context, err error) (apiErr APIErrorCode) {
	if err == nil {
		return ErrNone
	}

	// Errors that are generated by net.Conn and any context errors must be handled here.

Los códigos de estado en el rango de 400 significan que hubo un error por parte del cliente.

¿Recuerdas todos esos errores de **"404 Not Found"** (y chistes)?

## Usa `HTTPException`

Para devolver responses HTTP con errores al cliente, usa `HTTPException`.

### Importa `HTTPException`

{* ../../docs_src/handling_errors/tutorial001.py hl[1] *}

	return errors.Is(err, syscall.ENFILE) || errors.Is(err, syscall.EMFILE)
}

func osIsNotExist(err error) bool {
	return errors.Is(err, os.ErrNotExist)
}

func osIsPermission(err error) bool {
	return errors.Is(err, os.ErrPermission) || errors.Is(err, syscall.EROFS)
}

func osIsExist(err error) bool {
	return errors.Is(err, os.ErrExist)

# Handling Errors { #handling-errors }

There are many situations in which you need to notify an error to a client that is using your API.

This client could be a browser with a frontend, a code from someone else, an IoT device, etc.

You could need to tell the client that:

* The client doesn't have enough privileges for that operation.
* The client doesn't have access to that resource.
* The item the client was trying to access doesn't exist.
* etc.

func isErrBucketNotFound(err error) bool {
	if errors.Is(err, errVolumeNotFound) {
		return true
	}

	var bkNotFound BucketNotFound
	return errors.As(err, &bkNotFound)
}

// isErrReadQuorum check if the error type is InsufficientReadQuorum
func isErrReadQuorum(err error) bool {
	var rquorum InsufficientReadQuorum
	return errors.As(err, &rquorum)
}

Der Exceptionhandler wird einen `Request` und die Exception entgegennehmen.

{* ../../docs_src/handling_errors/tutorial004.py hl[2,14:16] *}

Wenn Sie nun `/items/foo` besuchen, erhalten Sie statt des Default-JSON-Errors:

```JSON
{
    "detail": [
        {
            "loc": [
                "path",
                "item_id"
            ],
            "msg": "value is not a valid integer",

	if err := DB.Create(&product).Error; err == nil {
		t.Errorf("should got failed to save, but error is nil")
	}

	if DB.First(&Product4{}, "name = ?", product.Name).Error == nil {
		t.Errorf("should got RecordNotFound, but got nil")
	}

	product = Product4{Name: "Product-2", Price: 100, Item: ProductItem{Code: "valid"}}
	if err := DB.Create(&product).Error; err != nil {
		t.Errorf("should create product, but got error %v", err)
	}