Add "ALL" capabilities support.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/util/strings.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+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 util
+
+import "strings"
+
+// InStringSlice checks whether a string is inside a string slice.
+// Comparison is case insensitive.
+func InStringSlice(ss []string, str string) bool {
+	for _, s := range ss {
+		if strings.ToLower(s) == strings.ToLower(str) {
+			return true
+		}
+	}
+	return false
+}
+
+// SubstractStringSlice substracts string from string slice.
+// Comparison is case insensitive.
+func SubstractStringSlice(ss []string, str string) []string {
+	var res []string
+	for _, s := range ss {
+		if strings.ToLower(s) == strings.ToLower(str) {
+			continue
+		}
+		res = append(res, s)
+	}
+	return res
+}