diff --git a/vendor/github.com/coreos/etcd/proxy/grpcproxy/leader.go b/vendor/github.com/coreos/etcd/proxy/grpcproxy/leader.go
new file mode 100644
index 0000000..042c949
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/proxy/grpcproxy/leader.go
@@ -0,0 +1,115 @@
+// Copyright 2017 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 grpcproxy
+
+import (
+	"context"
+	"math"
+	"sync"
+
+	"github.com/coreos/etcd/clientv3"
+	"github.com/coreos/etcd/etcdserver/api/v3rpc/rpctypes"
+
+	"golang.org/x/time/rate"
+	"google.golang.org/grpc"
+)
+
+const (
+	lostLeaderKey  = "__lostleader" // watched to detect leader loss
+	retryPerSecond = 10
+)
+
+type leader struct {
+	ctx context.Context
+	w   clientv3.Watcher
+	// mu protects leaderc updates.
+	mu       sync.RWMutex
+	leaderc  chan struct{}
+	disconnc chan struct{}
+	donec    chan struct{}
+}
+
+func newLeader(ctx context.Context, w clientv3.Watcher) *leader {
+	l := &leader{
+		ctx:      clientv3.WithRequireLeader(ctx),
+		w:        w,
+		leaderc:  make(chan struct{}),
+		disconnc: make(chan struct{}),
+		donec:    make(chan struct{}),
+	}
+	// begin assuming leader is lost
+	close(l.leaderc)
+	go l.recvLoop()
+	return l
+}
+
+func (l *leader) recvLoop() {
+	defer close(l.donec)
+
+	limiter := rate.NewLimiter(rate.Limit(retryPerSecond), retryPerSecond)
+	rev := int64(math.MaxInt64 - 2)
+	for limiter.Wait(l.ctx) == nil {
+		wch := l.w.Watch(l.ctx, lostLeaderKey, clientv3.WithRev(rev), clientv3.WithCreatedNotify())
+		cresp, ok := <-wch
+		if !ok {
+			l.loseLeader()
+			continue
+		}
+		if cresp.Err() != nil {
+			l.loseLeader()
+			if rpctypes.ErrorDesc(cresp.Err()) == grpc.ErrClientConnClosing.Error() {
+				close(l.disconnc)
+				return
+			}
+			continue
+		}
+		l.gotLeader()
+		<-wch
+		l.loseLeader()
+	}
+}
+
+func (l *leader) loseLeader() {
+	l.mu.RLock()
+	defer l.mu.RUnlock()
+	select {
+	case <-l.leaderc:
+	default:
+		close(l.leaderc)
+	}
+}
+
+// gotLeader will force update the leadership status to having a leader.
+func (l *leader) gotLeader() {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	select {
+	case <-l.leaderc:
+		l.leaderc = make(chan struct{})
+	default:
+	}
+}
+
+func (l *leader) disconnectNotify() <-chan struct{} { return l.disconnc }
+
+func (l *leader) stopNotify() <-chan struct{} { return l.donec }
+
+// lostNotify returns a channel that is closed if there has been
+// a leader loss not yet followed by a leader reacquire.
+func (l *leader) lostNotify() <-chan struct{} {
+	l.mu.RLock()
+	defer l.mu.RUnlock()
+	return l.leaderc
+}