distribution/registry/api/errcode/errors.go
2015-06-18 18:00:26 -07:00

229 lines
5.4 KiB
Go

package errcode
import (
"encoding/json"
"fmt"
"strings"
)
// ErrorCoder is the base interface for ErrorCode and Error allowing
// users of each to just call ErrorCode to get the real ID of each
type ErrorCoder interface {
ErrorCode() ErrorCode
}
// ErrorCode represents the error type. The errors are serialized via strings
// and the integer format may change and should *never* be exported.
type ErrorCode int
// ErrorCode just returns itself
func (ec ErrorCode) ErrorCode() ErrorCode {
return ec
}
// Error returns the ID/Value
func (ec ErrorCode) Error() string {
return ec.Descriptor().Value
}
// Descriptor returns the descriptor for the error code.
func (ec ErrorCode) Descriptor() ErrorDescriptor {
d, ok := errorCodeToDescriptors[ec]
if !ok {
return ErrorCodeUnknown.Descriptor()
}
return d
}
// String returns the canonical identifier for this error code.
func (ec ErrorCode) String() string {
return ec.Descriptor().Value
}
// Message returned the human-readable error message for this error code.
func (ec ErrorCode) Message() string {
return ec.Descriptor().Message
}
// MarshalText encodes the receiver into UTF-8-encoded text and returns the
// result.
func (ec ErrorCode) MarshalText() (text []byte, err error) {
return []byte(ec.String()), nil
}
// UnmarshalText decodes the form generated by MarshalText.
func (ec *ErrorCode) UnmarshalText(text []byte) error {
desc, ok := idToDescriptors[string(text)]
if !ok {
desc = ErrorCodeUnknown.Descriptor()
}
*ec = desc.Code
return nil
}
// WithDetail creates a new Error struct based on the passed-in info and
// set the Detail property appropriately
func (ec ErrorCode) WithDetail(detail interface{}) Error {
if err, ok := detail.(error); ok {
detail = err.Error()
}
return Error{
Code: ec,
Detail: detail,
}
}
// Error provides a wrapper around ErrorCode with extra Details provided.
type Error struct {
Code ErrorCode `json:"code"`
Detail interface{} `json:"detail,omitempty"`
}
// ErrorCode returns the ID/Value of this Error
func (e Error) ErrorCode() ErrorCode {
return e.Code
}
// Error returns a human readable representation of the error.
func (e Error) Error() string {
return fmt.Sprintf("%s: %s",
strings.ToLower(strings.Replace(e.Code.String(), "_", " ", -1)),
e.Code.Message())
}
// Message returned the human-readable error message for this Error
func (e Error) Message() string {
return e.Code.Message()
}
// ErrorDescriptor provides relevant information about a given error code.
type ErrorDescriptor struct {
// Code is the error code that this descriptor describes.
Code ErrorCode
// Value provides a unique, string key, often captilized with
// underscores, to identify the error code. This value is used as the
// keyed value when serializing api errors.
Value string
// Message is a short, human readable decription of the error condition
// included in API responses.
Message string
// Description provides a complete account of the errors purpose, suitable
// for use in documentation.
Description string
// HTTPStatusCode provides the http status code that is associated with
// this error condition.
HTTPStatusCode int
}
// ParseErrorCode returns the value by the string error code.
// `ErrorCodeUnknown` will be returned if the error is not known.
func ParseErrorCode(value string) ErrorCode {
ed, ok := idToDescriptors[value]
if ok {
return ed.Code
}
return ErrorCodeUnknown
}
// Errors provides the envelope for multiple errors and a few sugar methods
// for use within the application.
type Errors []error
func (errs Errors) Error() string {
switch len(errs) {
case 0:
return "<nil>"
case 1:
return errs[0].Error()
default:
msg := "errors:\n"
for _, err := range errs {
msg += err.Error() + "\n"
}
return msg
}
}
// Len returns the current number of errors.
func (errs Errors) Len() int {
return len(errs)
}
// jsonError extends Error with 'Message' so that we can include the
// error text, just in case the receiver of the JSON doesn't have this
// particular ErrorCode registered
type jsonError struct {
Code ErrorCode `json:"code"`
Message string `json:"message"`
Detail interface{} `json:"detail,omitempty"`
}
// MarshalJSON converts slice of error, ErrorCode or Error into a
// slice of Error - then serializes
func (errs Errors) MarshalJSON() ([]byte, error) {
var tmpErrs struct {
Errors []jsonError `json:"errors,omitempty"`
}
for _, daErr := range errs {
var err Error
switch daErr.(type) {
case ErrorCode:
err = daErr.(ErrorCode).WithDetail(nil)
case Error:
err = daErr.(Error)
default:
err = ErrorCodeUnknown.WithDetail(daErr)
}
tmpErrs.Errors = append(tmpErrs.Errors, jsonError{
Code: err.Code,
Message: err.Message(),
Detail: err.Detail,
})
}
return json.Marshal(tmpErrs)
}
// UnmarshalJSON deserializes []Error and then converts it into slice of
// Error or ErrorCode
func (errs *Errors) UnmarshalJSON(data []byte) error {
var tmpErrs struct {
Errors []jsonError
}
if err := json.Unmarshal(data, &tmpErrs); err != nil {
return err
}
var newErrs Errors
for _, daErr := range tmpErrs.Errors {
if daErr.Detail == nil {
// Error's w/o details get converted to ErrorCode
newErrs = append(newErrs, daErr.Code)
} else {
// Error's w/ details are untouched
newErrs = append(newErrs, Error{
Code: daErr.Code,
Detail: daErr.Detail,
})
}
}
*errs = newErrs
return nil
}