registry: convert AWS S3 error to correct errcode

registry/api/errcode/handler.go

@@ -3,6 +3,9 @@ package errcode
 import (
 	"encoding/json"
 	"net/http"
+
+	"github.com/aws/aws-sdk-go/aws/awserr"
+	"github.com/docker/distribution/registry/storage/driver"
 )
 
 // ServeJSON attempts to serve the errcode in a JSON envelope. It marshals err
@@ -18,13 +21,27 @@ func ServeJSON(w http.ResponseWriter, err error) error {
 			break
 		}
 
+		for i := range errs {
+			if err2, ok := errs[i].(Error); ok {
+				errs[i] = replaceError(err2)
+			}
+		}
+
 		if err, ok := errs[0].(ErrorCoder); ok {
 			sc = err.ErrorCode().Descriptor().HTTPStatusCode
 		}
 	case ErrorCoder:
+		if err2, ok := errs.(Error); ok {
+			errs = replaceError(err2)
+		}
+
 		sc = errs.ErrorCode().Descriptor().HTTPStatusCode
 		err = Errors{err} // create an envelope.
 	default:
+		if err2, ok := err.(Error); ok {
+			err = replaceError(err2)
+		}
+
 		// We just have an unhandled error type, so just place in an envelope
 		// and move along.
 		err = Errors{err}
@@ -38,3 +55,29 @@ func ServeJSON(w http.ResponseWriter, err error) error {
 
 	return json.NewEncoder(w).Encode(err)
 }
+
+func replaceError(e Error) Error {
+	serr, ok := e.Detail.(driver.Error)
+	if !ok {
+		return e
+	}
+
+	err, ok := serr.Enclosed.(awserr.RequestFailure)
+	if !ok {
+		return e
+	}
+
+	code := ErrorCodeUnknown
+	switch err.StatusCode() {
+	case http.StatusForbidden:
+		code = ErrorCodeDenied
+	case http.StatusServiceUnavailable:
+		code = ErrorCodeUnavailable
+	case http.StatusUnauthorized:
+		code = ErrorCodeUnauthorized
+	case http.StatusTooManyRequests:
+		code = ErrorCodeTooManyRequests
+	}
+
+	return code.WithDetail(err.Code())
+}