1 files changed, 79 insertions, 0 deletions
diff --git a/pkg/registry/error.go b/pkg/registry/error.go
new file mode 100644
index 0000000..f8e126d
--- /dev/null
+++ b/pkg/registry/error.go
@@ -0,0 +1,79 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package registry
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+type regError struct {
+	Status  int
+	Code    string
+	Message string
+}
+
+func (r *regError) Write(resp http.ResponseWriter) error {
+	resp.WriteHeader(r.Status)
+
+	type err struct {
+		Code    string `json:"code"`
+		Message string `json:"message"`
+	}
+	type wrap struct {
+		Errors []err `json:"errors"`
+	}
+	return json.NewEncoder(resp).Encode(wrap{
+		Errors: []err{
+			{
+				Code:    r.Code,
+				Message: r.Message,
+			},
+		},
+	})
+}
+
+// regErrInternal returns an internal server error.
+func regErrInternal(err error) *regError {
+	return &regError{
+		Status:  http.StatusInternalServerError,
+		Code:    "INTERNAL_SERVER_ERROR",
+		Message: err.Error(),
+	}
+}
+
+var regErrBlobUnknown = &regError{
+	Status:  http.StatusNotFound,
+	Code:    "BLOB_UNKNOWN",
+	Message: "Unknown blob",
+}
+
+var regErrUnsupported = &regError{
+	Status:  http.StatusMethodNotAllowed,
+	Code:    "UNSUPPORTED",
+	Message: "Unsupported operation",
+}
+
+var regErrDigestMismatch = &regError{
+	Status:  http.StatusBadRequest,
+	Code:    "DIGEST_INVALID",
+	Message: "digest does not match contents",
+}
+
+var regErrDigestInvalid = &regError{
+	Status:  http.StatusBadRequest,
+	Code:    "NAME_INVALID",
+	Message: "invalid digest",
+}