distribution/registry/client/errors.go

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package client
import (
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"net/http"
"github.com/docker/distribution/registry/api/errcode"
"github.com/docker/distribution/registry/client/auth/challenge"
)
// ErrNoErrorsInBody is returned when an HTTP response body parses to an empty
// errcode.Errors slice.
var ErrNoErrorsInBody = errors.New("no error details found in HTTP response body")
// UnexpectedHTTPStatusError is returned when an unexpected HTTP status is
// returned when making a registry api call.
type UnexpectedHTTPStatusError struct {
Status string
}
func (e *UnexpectedHTTPStatusError) Error() string {
return fmt.Sprintf("received unexpected HTTP status: %s", e.Status)
}
// UnexpectedHTTPResponseError is returned when an expected HTTP status code
// is returned, but the content was unexpected and failed to be parsed.
type UnexpectedHTTPResponseError struct {
ParseErr error
StatusCode int
Response []byte
}
func (e *UnexpectedHTTPResponseError) Error() string {
return fmt.Sprintf("error parsing HTTP %d response body: %s: %q", e.StatusCode, e.ParseErr.Error(), string(e.Response))
}
// OAuthError is returned when the request could not be authorized
// using the provided oauth token. This could represent a lack of
// permission or invalid token given from a token server.
// See https://tools.ietf.org/html/rfc6750#section-3
type OAuthError struct {
// ErrorCode is a code defined in https://tools.ietf.org/html/rfc6750#section-3.1
ErrorCode string
// Description is the error description associated with the error code
Description string
}
func (e *OAuthError) Error() string {
if e.Description != "" {
return fmt.Sprintf("oauth error %q: %s", e.ErrorCode, e.Description)
}
return fmt.Sprintf("oauth error %q", e.ErrorCode)
}
func parseHTTPErrorResponse(statusCode int, r io.Reader) error {
var errors errcode.Errors
body, err := ioutil.ReadAll(r)
if err != nil {
return err
}
// For backward compatibility, handle irregularly formatted
// messages that contain a "details" field.
var detailsErr struct {
Details string `json:"details"`
}
err = json.Unmarshal(body, &detailsErr)
if err == nil && detailsErr.Details != "" {
switch statusCode {
case http.StatusUnauthorized:
return errcode.ErrorCodeUnauthorized.WithMessage(detailsErr.Details)
case http.StatusTooManyRequests:
return errcode.ErrorCodeTooManyRequests.WithMessage(detailsErr.Details)
default:
return errcode.ErrorCodeUnknown.WithMessage(detailsErr.Details)
}
}
if err := json.Unmarshal(body, &errors); err != nil {
return &UnexpectedHTTPResponseError{
ParseErr: err,
StatusCode: statusCode,
Response: body,
}
}
if len(errors) == 0 {
// If there was no error specified in the body, return
// UnexpectedHTTPResponseError.
return &UnexpectedHTTPResponseError{
ParseErr: ErrNoErrorsInBody,
StatusCode: statusCode,
Response: body,
}
}
return errors
}
// HandleErrorResponse returns error parsed from HTTP response for an
// unsuccessful HTTP response code (in the range 400 - 499 inclusive). An
// UnexpectedHTTPStatusError returned for response code outside of expected
// range.
func HandleErrorResponse(resp *http.Response) error {
if resp.StatusCode >= 400 && resp.StatusCode < 500 {
// Check for OAuth errors within the `WWW-Authenticate` header first
for _, c := range challenge.ResponseChallenges(resp) {
if c.Scheme == "bearer" {
errStr := c.Parameters["error"]
if errStr != "" {
return &OAuthError{
ErrorCode: errStr,
Description: c.Parameters["error_description"],
}
}
}
}
err := parseHTTPErrorResponse(resp.StatusCode, resp.Body)
if uErr, ok := err.(*UnexpectedHTTPResponseError); ok && resp.StatusCode == 401 {
return errcode.ErrorCodeUnauthorized.WithDetail(uErr.Response)
}
return err
}
return &UnexpectedHTTPStatusError{Status: resp.Status}
}
// SuccessStatus returns true if the argument is a successful HTTP response
// code (in the range 200 - 399 inclusive).
func SuccessStatus(status int) bool {
return status >= 200 && status <= 399
}