// If this is already a Err, do nothing
	if e, ok := err.(Err); ok {
		return e
	}

	// Show a generic message for known golang errors
	if errors.Is(err, syscall.EADDRINUSE) {
		return ErrPortAlreadyInUse(err).Msg("Specified port is already in use")
	} else if errors.Is(err, syscall.EACCES) || errors.Is(err, syscall.EPERM) {
		if netErr, ok := err.(*net.OpError); ok {

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package hash

import (
	"errors"
	"fmt"
)

// SHA256Mismatch - when content sha256 does not match with what was sent from client.
type SHA256Mismatch struct {
	ExpectedSHA256   string
	CalculatedSHA256 string
}

	// 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")

package grid

import (
	"errors"
	"fmt"
)

var (
	// ErrUnknownHandler is returned when an unknown handler is requested.
	ErrUnknownHandler = errors.New("unknown mux handler")

	// ErrHandlerAlreadyExists is returned when a handler is already registered.
	ErrHandlerAlreadyExists = errors.New("mux handler already exists")

The status codes in the 400 range mean that there was an error from the client.

Remember all those **"404 Not Found"** errors (and jokes)?

## Use `HTTPException`

To return HTTP responses with errors to the client you use `HTTPException`.

### Import `HTTPException`

```Python hl_lines="1"
{!../../docs_src/handling_errors/tutorial001.py!}
```

package jstream

import (
	"fmt"
	"strconv"
)

// Predefined errors
var (
	ErrSyntax        = DecoderError{msg: "invalid character"}
	ErrUnexpectedEOF = DecoderError{msg: "unexpected end of JSON input"}
	ErrMaxDepth      = DecoderError{msg: "maximum recursion depth exceeded"}
)

type errPos [2]int // line number, byte offset where error occurred

// DecoderError contains a detailed decoding error.
type DecoderError struct {

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")

	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)

}

// 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.