diff --git a/vendor/github.com/coreos/etcd/clientv3/balancer/resolver/endpoint/endpoint.go b/vendor/github.com/coreos/etcd/clientv3/balancer/resolver/endpoint/endpoint.go
new file mode 100644
index 0000000..864b5df
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/clientv3/balancer/resolver/endpoint/endpoint.go
@@ -0,0 +1,247 @@
+// 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 endpoint resolves etcd entpoints using grpc targets of the form 'endpoint://<id>/<endpoint>'.
+package endpoint
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/url"
+	"strings"
+	"sync"
+
+	"google.golang.org/grpc/resolver"
+)
+
+const scheme = "endpoint"
+
+var (
+	targetPrefix = fmt.Sprintf("%s://", scheme)
+
+	bldr *builder
+)
+
+func init() {
+	bldr = &builder{
+		resolverGroups: make(map[string]*ResolverGroup),
+	}
+	resolver.Register(bldr)
+}
+
+type builder struct {
+	mu             sync.RWMutex
+	resolverGroups map[string]*ResolverGroup
+}
+
+// NewResolverGroup creates a new ResolverGroup with the given id.
+func NewResolverGroup(id string) (*ResolverGroup, error) {
+	return bldr.newResolverGroup(id)
+}
+
+// ResolverGroup keeps all endpoints of resolvers using a common endpoint://<id>/ target
+// up-to-date.
+type ResolverGroup struct {
+	mu        sync.RWMutex
+	id        string
+	endpoints []string
+	resolvers []*Resolver
+}
+
+func (e *ResolverGroup) addResolver(r *Resolver) {
+	e.mu.Lock()
+	addrs := epsToAddrs(e.endpoints...)
+	e.resolvers = append(e.resolvers, r)
+	e.mu.Unlock()
+	r.cc.NewAddress(addrs)
+}
+
+func (e *ResolverGroup) removeResolver(r *Resolver) {
+	e.mu.Lock()
+	for i, er := range e.resolvers {
+		if er == r {
+			e.resolvers = append(e.resolvers[:i], e.resolvers[i+1:]...)
+			break
+		}
+	}
+	e.mu.Unlock()
+}
+
+// SetEndpoints updates the endpoints for ResolverGroup. All registered resolver are updated
+// immediately with the new endpoints.
+func (e *ResolverGroup) SetEndpoints(endpoints []string) {
+	addrs := epsToAddrs(endpoints...)
+	e.mu.Lock()
+	e.endpoints = endpoints
+	for _, r := range e.resolvers {
+		r.cc.NewAddress(addrs)
+	}
+	e.mu.Unlock()
+}
+
+// Target constructs a endpoint target using the endpoint id of the ResolverGroup.
+func (e *ResolverGroup) Target(endpoint string) string {
+	return Target(e.id, endpoint)
+}
+
+// Target constructs a endpoint resolver target.
+func Target(id, endpoint string) string {
+	return fmt.Sprintf("%s://%s/%s", scheme, id, endpoint)
+}
+
+// IsTarget checks if a given target string in an endpoint resolver target.
+func IsTarget(target string) bool {
+	return strings.HasPrefix(target, "endpoint://")
+}
+
+func (e *ResolverGroup) Close() {
+	bldr.close(e.id)
+}
+
+// Build creates or reuses an etcd resolver for the etcd cluster name identified by the authority part of the target.
+func (b *builder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+	if len(target.Authority) < 1 {
+		return nil, fmt.Errorf("'etcd' target scheme requires non-empty authority identifying etcd cluster being routed to")
+	}
+	id := target.Authority
+	es, err := b.getResolverGroup(id)
+	if err != nil {
+		return nil, fmt.Errorf("failed to build resolver: %v", err)
+	}
+	r := &Resolver{
+		endpointID: id,
+		cc:         cc,
+	}
+	es.addResolver(r)
+	return r, nil
+}
+
+func (b *builder) newResolverGroup(id string) (*ResolverGroup, error) {
+	b.mu.RLock()
+	_, ok := b.resolverGroups[id]
+	b.mu.RUnlock()
+	if ok {
+		return nil, fmt.Errorf("Endpoint already exists for id: %s", id)
+	}
+
+	es := &ResolverGroup{id: id}
+	b.mu.Lock()
+	b.resolverGroups[id] = es
+	b.mu.Unlock()
+	return es, nil
+}
+
+func (b *builder) getResolverGroup(id string) (*ResolverGroup, error) {
+	b.mu.RLock()
+	es, ok := b.resolverGroups[id]
+	b.mu.RUnlock()
+	if !ok {
+		return nil, fmt.Errorf("ResolverGroup not found for id: %s", id)
+	}
+	return es, nil
+}
+
+func (b *builder) close(id string) {
+	b.mu.Lock()
+	delete(b.resolverGroups, id)
+	b.mu.Unlock()
+}
+
+func (b *builder) Scheme() string {
+	return scheme
+}
+
+// Resolver provides a resolver for a single etcd cluster, identified by name.
+type Resolver struct {
+	endpointID string
+	cc         resolver.ClientConn
+	sync.RWMutex
+}
+
+// TODO: use balancer.epsToAddrs
+func epsToAddrs(eps ...string) (addrs []resolver.Address) {
+	addrs = make([]resolver.Address, 0, len(eps))
+	for _, ep := range eps {
+		addrs = append(addrs, resolver.Address{Addr: ep})
+	}
+	return addrs
+}
+
+func (*Resolver) ResolveNow(o resolver.ResolveNowOption) {}
+
+func (r *Resolver) Close() {
+	es, err := bldr.getResolverGroup(r.endpointID)
+	if err != nil {
+		return
+	}
+	es.removeResolver(r)
+}
+
+// ParseEndpoint endpoint parses an endpoint of the form
+// (http|https)://<host>*|(unix|unixs)://<path>)
+// and returns a protocol ('tcp' or 'unix'),
+// host (or filepath if a unix socket),
+// scheme (http, https, unix, unixs).
+func ParseEndpoint(endpoint string) (proto string, host string, scheme string) {
+	proto = "tcp"
+	host = endpoint
+	url, uerr := url.Parse(endpoint)
+	if uerr != nil || !strings.Contains(endpoint, "://") {
+		return proto, host, scheme
+	}
+	scheme = url.Scheme
+
+	// strip scheme:// prefix since grpc dials by host
+	host = url.Host
+	switch url.Scheme {
+	case "http", "https":
+	case "unix", "unixs":
+		proto = "unix"
+		host = url.Host + url.Path
+	default:
+		proto, host = "", ""
+	}
+	return proto, host, scheme
+}
+
+// ParseTarget parses a endpoint://<id>/<endpoint> string and returns the parsed id and endpoint.
+// If the target is malformed, an error is returned.
+func ParseTarget(target string) (string, string, error) {
+	noPrefix := strings.TrimPrefix(target, targetPrefix)
+	if noPrefix == target {
+		return "", "", fmt.Errorf("malformed target, %s prefix is required: %s", targetPrefix, target)
+	}
+	parts := strings.SplitN(noPrefix, "/", 2)
+	if len(parts) != 2 {
+		return "", "", fmt.Errorf("malformed target, expected %s://<id>/<endpoint>, but got %s", scheme, target)
+	}
+	return parts[0], parts[1], nil
+}
+
+// Dialer dials a endpoint using net.Dialer.
+// Context cancelation and timeout are supported.
+func Dialer(ctx context.Context, dialEp string) (net.Conn, error) {
+	proto, host, _ := ParseEndpoint(dialEp)
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	default:
+	}
+	dialer := &net.Dialer{}
+	if deadline, ok := ctx.Deadline(); ok {
+		dialer.Deadline = deadline
+	}
+	return dialer.DialContext(ctx, proto, host)
+}