Add GetReference()

pkg/api/ref.go

@@ -0,0 +1,52 @@
+/*
+Copyright 2014 Google Inc. 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 api
+
+import (
+	"fmt"
+	"regexp"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
+)
+
+var versionFromSelfLink = regexp.MustCompile("/api/([^/]*)/")
+
+// GetReference returns an ObjectReference which refers to the given
+// object, or an error if the object doesn't follow the conventions
+// that would allow this.
+func GetReference(obj runtime.Object) (*ObjectReference, error) {
+	jsonBase, err := runtime.FindJSONBase(obj)
+	if err != nil {
+		return nil, err
+	}
+	_, kind, err := Scheme.ObjectVersionAndKind(obj)
+	if err != nil {
+		return nil, err
+	}
+	version := versionFromSelfLink.FindStringSubmatch(jsonBase.SelfLink())
+	if len(version) < 2 {
+		return nil, fmt.Errorf("unexpected self link format: %v", jsonBase.SelfLink())
+	}
+	return &ObjectReference{
+		Kind:       kind,
+		APIVersion: version[1],
+		// TODO: correct Name and UID when JSONBase makes a distinction
+		Name:            jsonBase.ID(),
+		UID:             jsonBase.ID(),
+		ResourceVersion: jsonBase.ResourceVersion(),
+	}, nil
+}