From ec636bbfd246e822bc20c8b1d5e06de965a9469d Mon Sep 17 00:00:00 2001
From: Aaron Lehmann <aaron.lehmann@docker.com>
Date: Wed, 20 Jan 2016 14:45:08 -0800
Subject: [PATCH] Handle nonstandard token endpoint errors

https://github.com/docker/distribution/pull/1249 changed token fetching
to parse HTTP error response bodies as serialized errcodes. However,
Docker Hub's authentication endpoint does not return error bodies in
this format. To work around this, convert its format into
ErrCodeUnauthorized or ErrCodeUnknown.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
---
 registry/api/errcode/errors.go |  9 +++++++++
 registry/client/errors.go      | 19 ++++++++++++++++---
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/registry/api/errcode/errors.go b/registry/api/errcode/errors.go
index 9a405d21..6d9bb4b6 100644
--- a/registry/api/errcode/errors.go
+++ b/registry/api/errcode/errors.go
@@ -69,6 +69,15 @@ func (ec *ErrorCode) UnmarshalText(text []byte) error {
 	return nil
 }
 
+// WithMessage creates a new Error struct based on the passed-in info and
+// overrides the Message property.
+func (ec ErrorCode) WithMessage(message string) Error {
+	return Error{
+		Code:    ec,
+		Message: message,
+	}
+}
+
 // 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 {
diff --git a/registry/client/errors.go b/registry/client/errors.go
index 8e3cb108..a528a865 100644
--- a/registry/client/errors.go
+++ b/registry/client/errors.go
@@ -31,13 +31,26 @@ func (e *UnexpectedHTTPResponseError) Error() string {
 	return fmt.Sprintf("Error parsing HTTP response: %s: %q", e.ParseErr.Error(), string(e.Response))
 }
 
-func parseHTTPErrorResponse(r io.Reader) error {
+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 != "" {
+		if statusCode == http.StatusUnauthorized {
+			return errcode.ErrorCodeUnauthorized.WithMessage(detailsErr.Details)
+		}
+		return errcode.ErrorCodeUnknown.WithMessage(detailsErr.Details)
+	}
+
 	if err := json.Unmarshal(body, &errors); err != nil {
 		return &UnexpectedHTTPResponseError{
 			ParseErr: err,
@@ -53,14 +66,14 @@ func parseHTTPErrorResponse(r io.Reader) error {
 // range.
 func HandleErrorResponse(resp *http.Response) error {
 	if resp.StatusCode == 401 {
-		err := parseHTTPErrorResponse(resp.Body)
+		err := parseHTTPErrorResponse(resp.StatusCode, resp.Body)
 		if uErr, ok := err.(*UnexpectedHTTPResponseError); ok {
 			return errcode.ErrorCodeUnauthorized.WithDetail(uErr.Response)
 		}
 		return err
 	}
 	if resp.StatusCode >= 400 && resp.StatusCode < 500 {
-		return parseHTTPErrorResponse(resp.Body)
+		return parseHTTPErrorResponse(resp.StatusCode, resp.Body)
 	}
 	return &UnexpectedHTTPStatusError{Status: resp.Status}
 }