Flag-compatible IP type

pkg/util/net.go

@@ -0,0 +1,37 @@
+/*
+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 util
+
+import (
+	"fmt"
+	"net"
+)
+
+// IP adapts net.IP for use as a flag.
+type IP net.IP
+
+func (ip IP) String() string {
+	return net.IP(ip).String()
+}
+
+func (ip *IP) Set(value string) error {
+	*ip = IP(net.ParseIP(value))
+	if *ip == nil {
+		return fmt.Errorf("invalid IP address: '%s'", value)
+	}
+	return nil
+}