diff --git a/vendor/go.etcd.io/etcd/pkg/flags/unique_urls.go b/vendor/go.etcd.io/etcd/pkg/flags/unique_urls.go
new file mode 100644
index 0000000..9b4178c
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/pkg/flags/unique_urls.go
@@ -0,0 +1,92 @@
+// Copyright 2018 The etcd 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 flags
+
+import (
+	"flag"
+	"net/url"
+	"sort"
+	"strings"
+
+	"go.etcd.io/etcd/pkg/types"
+)
+
+// UniqueURLs contains unique URLs
+// with non-URL exceptions.
+type UniqueURLs struct {
+	Values  map[string]struct{}
+	uss     []url.URL
+	Allowed map[string]struct{}
+}
+
+// Set parses a command line set of URLs formatted like:
+// http://127.0.0.1:2380,http://10.1.1.2:80
+// Implements "flag.Value" interface.
+func (us *UniqueURLs) Set(s string) error {
+	if _, ok := us.Values[s]; ok {
+		return nil
+	}
+	if _, ok := us.Allowed[s]; ok {
+		us.Values[s] = struct{}{}
+		return nil
+	}
+	ss, err := types.NewURLs(strings.Split(s, ","))
+	if err != nil {
+		return err
+	}
+	us.Values = make(map[string]struct{})
+	us.uss = make([]url.URL, 0)
+	for _, v := range ss {
+		us.Values[v.String()] = struct{}{}
+		us.uss = append(us.uss, v)
+	}
+	return nil
+}
+
+// String implements "flag.Value" interface.
+func (us *UniqueURLs) String() string {
+	all := make([]string, 0, len(us.Values))
+	for u := range us.Values {
+		all = append(all, u)
+	}
+	sort.Strings(all)
+	return strings.Join(all, ",")
+}
+
+// NewUniqueURLsWithExceptions implements "url.URL" slice as flag.Value interface.
+// Given value is to be separated by comma.
+func NewUniqueURLsWithExceptions(s string, exceptions ...string) *UniqueURLs {
+	us := &UniqueURLs{Values: make(map[string]struct{}), Allowed: make(map[string]struct{})}
+	for _, v := range exceptions {
+		us.Allowed[v] = struct{}{}
+	}
+	if s == "" {
+		return us
+	}
+	if err := us.Set(s); err != nil {
+		plog.Panicf("new UniqueURLs should never fail: %v", err)
+	}
+	return us
+}
+
+// UniqueURLsFromFlag returns a slice from urls got from the flag.
+func UniqueURLsFromFlag(fs *flag.FlagSet, urlsFlagName string) []url.URL {
+	return (*fs.Lookup(urlsFlagName).Value.(*UniqueURLs)).uss
+}
+
+// UniqueURLsMapFromFlag returns a map from url strings got from the flag.
+func UniqueURLsMapFromFlag(fs *flag.FlagSet, urlsFlagName string) map[string]struct{} {
+	return (*fs.Lookup(urlsFlagName).Value.(*UniqueURLs)).Values
+}