Abstract the error handling for the storage layer to eliminate the

direct etcd dependency.

pkg/storage/errors.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2015 The Kubernetes Authors 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 storage
+
+import (
+	etcdutil "k8s.io/kubernetes/pkg/storage/etcd/util"
+)
+
+// IsNotFound returns true if and only if err is "key" not found error.
+func IsNotFound(err error) bool {
+	// TODO: add alternate storage error here
+	return etcdutil.IsEtcdNotFound(err)
+}
+
+// IsNodeExist returns true if and only if err is an node already exist error.
+func IsNodeExist(err error) bool {
+	// TODO: add alternate storage error here
+	return etcdutil.IsEtcdNodeExist(err)
+}
+
+// IsUnreachable returns true if and only if err indicates the server could not be reached.
+func IsUnreachable(err error) bool {
+	// TODO: add alternate storage error here
+	return etcdutil.IsEtcdUnreachable(err)
+}
+
+// IsTestFailed returns true if and only if err is a write conflict.
+func IsTestFailed(err error) bool {
+	// TODO: add alternate storage error here
+	return etcdutil.IsEtcdTestFailed(err)
+}