This update provides:
1)  workaround around the build failures. In
summary, it forces the download of some packages during the build
process.
2) update the set of packages that should go inside the vendor
directory
3) Update the dockerfile to use go 1.10

Change-Id: I2bfd090ce0f25b0c10aa214755ae2da7e5384d60
diff --git a/vendor/github.com/coreos/etcd/clientv3/health_balancer.go b/vendor/github.com/coreos/etcd/clientv3/health_balancer.go
new file mode 100644
index 0000000..5918cba
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/clientv3/health_balancer.go
@@ -0,0 +1,609 @@
+// 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 clientv3
+
+import (
+	"context"
+	"errors"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+	"google.golang.org/grpc/status"
+)
+
+const (
+	minHealthRetryDuration = 3 * time.Second
+	unknownService         = "unknown service grpc.health.v1.Health"
+)
+
+// ErrNoAddrAvilable is returned by Get() when the balancer does not have
+// any active connection to endpoints at the time.
+// This error is returned only when opts.BlockingWait is true.
+var ErrNoAddrAvilable = status.Error(codes.Unavailable, "there is no address available")
+
+type healthCheckFunc func(ep string) (bool, error)
+
+type notifyMsg int
+
+const (
+	notifyReset notifyMsg = iota
+	notifyNext
+)
+
+// healthBalancer does the bare minimum to expose multiple eps
+// to the grpc reconnection code path
+type healthBalancer struct {
+	// addrs are the client's endpoint addresses for grpc
+	addrs []grpc.Address
+
+	// eps holds the raw endpoints from the client
+	eps []string
+
+	// notifyCh notifies grpc of the set of addresses for connecting
+	notifyCh chan []grpc.Address
+
+	// readyc closes once the first connection is up
+	readyc    chan struct{}
+	readyOnce sync.Once
+
+	// healthCheck checks an endpoint's health.
+	healthCheck        healthCheckFunc
+	healthCheckTimeout time.Duration
+
+	unhealthyMu        sync.RWMutex
+	unhealthyHostPorts map[string]time.Time
+
+	// mu protects all fields below.
+	mu sync.RWMutex
+
+	// upc closes when pinAddr transitions from empty to non-empty or the balancer closes.
+	upc chan struct{}
+
+	// downc closes when grpc calls down() on pinAddr
+	downc chan struct{}
+
+	// stopc is closed to signal updateNotifyLoop should stop.
+	stopc    chan struct{}
+	stopOnce sync.Once
+	wg       sync.WaitGroup
+
+	// donec closes when all goroutines are exited
+	donec chan struct{}
+
+	// updateAddrsC notifies updateNotifyLoop to update addrs.
+	updateAddrsC chan notifyMsg
+
+	// grpc issues TLS cert checks using the string passed into dial so
+	// that string must be the host. To recover the full scheme://host URL,
+	// have a map from hosts to the original endpoint.
+	hostPort2ep map[string]string
+
+	// pinAddr is the currently pinned address; set to the empty string on
+	// initialization and shutdown.
+	pinAddr string
+
+	closed bool
+}
+
+func newHealthBalancer(eps []string, timeout time.Duration, hc healthCheckFunc) *healthBalancer {
+	notifyCh := make(chan []grpc.Address)
+	addrs := eps2addrs(eps)
+	hb := &healthBalancer{
+		addrs:              addrs,
+		eps:                eps,
+		notifyCh:           notifyCh,
+		readyc:             make(chan struct{}),
+		healthCheck:        hc,
+		unhealthyHostPorts: make(map[string]time.Time),
+		upc:                make(chan struct{}),
+		stopc:              make(chan struct{}),
+		downc:              make(chan struct{}),
+		donec:              make(chan struct{}),
+		updateAddrsC:       make(chan notifyMsg),
+		hostPort2ep:        getHostPort2ep(eps),
+	}
+	if timeout < minHealthRetryDuration {
+		timeout = minHealthRetryDuration
+	}
+	hb.healthCheckTimeout = timeout
+
+	close(hb.downc)
+	go hb.updateNotifyLoop()
+	hb.wg.Add(1)
+	go func() {
+		defer hb.wg.Done()
+		hb.updateUnhealthy()
+	}()
+	return hb
+}
+
+func (b *healthBalancer) Start(target string, config grpc.BalancerConfig) error { return nil }
+
+func (b *healthBalancer) ConnectNotify() <-chan struct{} {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.upc
+}
+
+func (b *healthBalancer) ready() <-chan struct{} { return b.readyc }
+
+func (b *healthBalancer) endpoint(hostPort string) string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.hostPort2ep[hostPort]
+}
+
+func (b *healthBalancer) pinned() string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return b.pinAddr
+}
+
+func (b *healthBalancer) hostPortError(hostPort string, err error) {
+	if b.endpoint(hostPort) == "" {
+		logger.Lvl(4).Infof("clientv3/balancer: %q is stale (skip marking as unhealthy on %q)", hostPort, err.Error())
+		return
+	}
+
+	b.unhealthyMu.Lock()
+	b.unhealthyHostPorts[hostPort] = time.Now()
+	b.unhealthyMu.Unlock()
+	logger.Lvl(4).Infof("clientv3/balancer: %q is marked unhealthy (%q)", hostPort, err.Error())
+}
+
+func (b *healthBalancer) removeUnhealthy(hostPort, msg string) {
+	if b.endpoint(hostPort) == "" {
+		logger.Lvl(4).Infof("clientv3/balancer: %q was not in unhealthy (%q)", hostPort, msg)
+		return
+	}
+
+	b.unhealthyMu.Lock()
+	delete(b.unhealthyHostPorts, hostPort)
+	b.unhealthyMu.Unlock()
+	logger.Lvl(4).Infof("clientv3/balancer: %q is removed from unhealthy (%q)", hostPort, msg)
+}
+
+func (b *healthBalancer) countUnhealthy() (count int) {
+	b.unhealthyMu.RLock()
+	count = len(b.unhealthyHostPorts)
+	b.unhealthyMu.RUnlock()
+	return count
+}
+
+func (b *healthBalancer) isUnhealthy(hostPort string) (unhealthy bool) {
+	b.unhealthyMu.RLock()
+	_, unhealthy = b.unhealthyHostPorts[hostPort]
+	b.unhealthyMu.RUnlock()
+	return unhealthy
+}
+
+func (b *healthBalancer) cleanupUnhealthy() {
+	b.unhealthyMu.Lock()
+	for k, v := range b.unhealthyHostPorts {
+		if time.Since(v) > b.healthCheckTimeout {
+			delete(b.unhealthyHostPorts, k)
+			logger.Lvl(4).Infof("clientv3/balancer: removed %q from unhealthy after %v", k, b.healthCheckTimeout)
+		}
+	}
+	b.unhealthyMu.Unlock()
+}
+
+func (b *healthBalancer) liveAddrs() ([]grpc.Address, map[string]struct{}) {
+	unhealthyCnt := b.countUnhealthy()
+
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	hbAddrs := b.addrs
+	if len(b.addrs) == 1 || unhealthyCnt == 0 || unhealthyCnt == len(b.addrs) {
+		liveHostPorts := make(map[string]struct{}, len(b.hostPort2ep))
+		for k := range b.hostPort2ep {
+			liveHostPorts[k] = struct{}{}
+		}
+		return hbAddrs, liveHostPorts
+	}
+
+	addrs := make([]grpc.Address, 0, len(b.addrs)-unhealthyCnt)
+	liveHostPorts := make(map[string]struct{}, len(addrs))
+	for _, addr := range b.addrs {
+		if !b.isUnhealthy(addr.Addr) {
+			addrs = append(addrs, addr)
+			liveHostPorts[addr.Addr] = struct{}{}
+		}
+	}
+	return addrs, liveHostPorts
+}
+
+func (b *healthBalancer) updateUnhealthy() {
+	for {
+		select {
+		case <-time.After(b.healthCheckTimeout):
+			b.cleanupUnhealthy()
+			pinned := b.pinned()
+			if pinned == "" || b.isUnhealthy(pinned) {
+				select {
+				case b.updateAddrsC <- notifyNext:
+				case <-b.stopc:
+					return
+				}
+			}
+		case <-b.stopc:
+			return
+		}
+	}
+}
+
+func (b *healthBalancer) updateAddrs(eps ...string) {
+	np := getHostPort2ep(eps)
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	match := len(np) == len(b.hostPort2ep)
+	if match {
+		for k, v := range np {
+			if b.hostPort2ep[k] != v {
+				match = false
+				break
+			}
+		}
+	}
+	if match {
+		// same endpoints, so no need to update address
+		return
+	}
+
+	b.hostPort2ep = np
+	b.addrs, b.eps = eps2addrs(eps), eps
+
+	b.unhealthyMu.Lock()
+	b.unhealthyHostPorts = make(map[string]time.Time)
+	b.unhealthyMu.Unlock()
+}
+
+func (b *healthBalancer) next() {
+	b.mu.RLock()
+	downc := b.downc
+	b.mu.RUnlock()
+	select {
+	case b.updateAddrsC <- notifyNext:
+	case <-b.stopc:
+	}
+	// wait until disconnect so new RPCs are not issued on old connection
+	select {
+	case <-downc:
+	case <-b.stopc:
+	}
+}
+
+func (b *healthBalancer) updateNotifyLoop() {
+	defer close(b.donec)
+
+	for {
+		b.mu.RLock()
+		upc, downc, addr := b.upc, b.downc, b.pinAddr
+		b.mu.RUnlock()
+		// downc or upc should be closed
+		select {
+		case <-downc:
+			downc = nil
+		default:
+		}
+		select {
+		case <-upc:
+			upc = nil
+		default:
+		}
+		switch {
+		case downc == nil && upc == nil:
+			// stale
+			select {
+			case <-b.stopc:
+				return
+			default:
+			}
+		case downc == nil:
+			b.notifyAddrs(notifyReset)
+			select {
+			case <-upc:
+			case msg := <-b.updateAddrsC:
+				b.notifyAddrs(msg)
+			case <-b.stopc:
+				return
+			}
+		case upc == nil:
+			select {
+			// close connections that are not the pinned address
+			case b.notifyCh <- []grpc.Address{{Addr: addr}}:
+			case <-downc:
+			case <-b.stopc:
+				return
+			}
+			select {
+			case <-downc:
+				b.notifyAddrs(notifyReset)
+			case msg := <-b.updateAddrsC:
+				b.notifyAddrs(msg)
+			case <-b.stopc:
+				return
+			}
+		}
+	}
+}
+
+func (b *healthBalancer) notifyAddrs(msg notifyMsg) {
+	if msg == notifyNext {
+		select {
+		case b.notifyCh <- []grpc.Address{}:
+		case <-b.stopc:
+			return
+		}
+	}
+	b.mu.RLock()
+	pinAddr := b.pinAddr
+	downc := b.downc
+	b.mu.RUnlock()
+	addrs, hostPorts := b.liveAddrs()
+
+	var waitDown bool
+	if pinAddr != "" {
+		_, ok := hostPorts[pinAddr]
+		waitDown = !ok
+	}
+
+	select {
+	case b.notifyCh <- addrs:
+		if waitDown {
+			select {
+			case <-downc:
+			case <-b.stopc:
+			}
+		}
+	case <-b.stopc:
+	}
+}
+
+func (b *healthBalancer) Up(addr grpc.Address) func(error) {
+	if !b.mayPin(addr) {
+		return func(err error) {}
+	}
+
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	// gRPC might call Up after it called Close. We add this check
+	// to "fix" it up at application layer. Otherwise, will panic
+	// if b.upc is already closed.
+	if b.closed {
+		return func(err error) {}
+	}
+
+	// gRPC might call Up on a stale address.
+	// Prevent updating pinAddr with a stale address.
+	if !hasAddr(b.addrs, addr.Addr) {
+		return func(err error) {}
+	}
+
+	if b.pinAddr != "" {
+		logger.Lvl(4).Infof("clientv3/balancer: %q is up but not pinned (already pinned %q)", addr.Addr, b.pinAddr)
+		return func(err error) {}
+	}
+
+	// notify waiting Get()s and pin first connected address
+	close(b.upc)
+	b.downc = make(chan struct{})
+	b.pinAddr = addr.Addr
+	logger.Lvl(4).Infof("clientv3/balancer: pin %q", addr.Addr)
+
+	// notify client that a connection is up
+	b.readyOnce.Do(func() { close(b.readyc) })
+
+	return func(err error) {
+		// If connected to a black hole endpoint or a killed server, the gRPC ping
+		// timeout will induce a network I/O error, and retrying until success;
+		// finding healthy endpoint on retry could take several timeouts and redials.
+		// To avoid wasting retries, gray-list unhealthy endpoints.
+		b.hostPortError(addr.Addr, err)
+
+		b.mu.Lock()
+		b.upc = make(chan struct{})
+		close(b.downc)
+		b.pinAddr = ""
+		b.mu.Unlock()
+		logger.Lvl(4).Infof("clientv3/balancer: unpin %q (%q)", addr.Addr, err.Error())
+	}
+}
+
+func (b *healthBalancer) mayPin(addr grpc.Address) bool {
+	if b.endpoint(addr.Addr) == "" { // stale host:port
+		return false
+	}
+
+	b.unhealthyMu.RLock()
+	unhealthyCnt := len(b.unhealthyHostPorts)
+	failedTime, bad := b.unhealthyHostPorts[addr.Addr]
+	b.unhealthyMu.RUnlock()
+
+	b.mu.RLock()
+	skip := len(b.addrs) == 1 || unhealthyCnt == 0 || len(b.addrs) == unhealthyCnt
+	b.mu.RUnlock()
+	if skip || !bad {
+		return true
+	}
+
+	// prevent isolated member's endpoint from being infinitely retried, as follows:
+	//   1. keepalive pings detects GoAway with http2.ErrCodeEnhanceYourCalm
+	//   2. balancer 'Up' unpins with grpc: failed with network I/O error
+	//   3. grpc-healthcheck still SERVING, thus retry to pin
+	// instead, return before grpc-healthcheck if failed within healthcheck timeout
+	if elapsed := time.Since(failedTime); elapsed < b.healthCheckTimeout {
+		logger.Lvl(4).Infof("clientv3/balancer: %q is up but not pinned (failed %v ago, require minimum %v after failure)", addr.Addr, elapsed, b.healthCheckTimeout)
+		return false
+	}
+
+	if ok, _ := b.healthCheck(addr.Addr); ok {
+		b.removeUnhealthy(addr.Addr, "health check success")
+		return true
+	}
+
+	b.hostPortError(addr.Addr, errors.New("health check failed"))
+	return false
+}
+
+func (b *healthBalancer) Get(ctx context.Context, opts grpc.BalancerGetOptions) (grpc.Address, func(), error) {
+	var (
+		addr   string
+		closed bool
+	)
+
+	// If opts.BlockingWait is false (for fail-fast RPCs), it should return
+	// an address it has notified via Notify immediately instead of blocking.
+	if !opts.BlockingWait {
+		b.mu.RLock()
+		closed = b.closed
+		addr = b.pinAddr
+		b.mu.RUnlock()
+		if closed {
+			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
+		}
+		if addr == "" {
+			return grpc.Address{Addr: ""}, nil, ErrNoAddrAvilable
+		}
+		return grpc.Address{Addr: addr}, func() {}, nil
+	}
+
+	for {
+		b.mu.RLock()
+		ch := b.upc
+		b.mu.RUnlock()
+		select {
+		case <-ch:
+		case <-b.donec:
+			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
+		case <-ctx.Done():
+			return grpc.Address{Addr: ""}, nil, ctx.Err()
+		}
+		b.mu.RLock()
+		closed = b.closed
+		addr = b.pinAddr
+		b.mu.RUnlock()
+		// Close() which sets b.closed = true can be called before Get(), Get() must exit if balancer is closed.
+		if closed {
+			return grpc.Address{Addr: ""}, nil, grpc.ErrClientConnClosing
+		}
+		if addr != "" {
+			break
+		}
+	}
+	return grpc.Address{Addr: addr}, func() {}, nil
+}
+
+func (b *healthBalancer) Notify() <-chan []grpc.Address { return b.notifyCh }
+
+func (b *healthBalancer) Close() error {
+	b.mu.Lock()
+	// In case gRPC calls close twice. TODO: remove the checking
+	// when we are sure that gRPC wont call close twice.
+	if b.closed {
+		b.mu.Unlock()
+		<-b.donec
+		return nil
+	}
+	b.closed = true
+	b.stopOnce.Do(func() { close(b.stopc) })
+	b.pinAddr = ""
+
+	// In the case of following scenario:
+	//	1. upc is not closed; no pinned address
+	// 	2. client issues an RPC, calling invoke(), which calls Get(), enters for loop, blocks
+	// 	3. client.conn.Close() calls balancer.Close(); closed = true
+	// 	4. for loop in Get() never exits since ctx is the context passed in by the client and may not be canceled
+	// we must close upc so Get() exits from blocking on upc
+	select {
+	case <-b.upc:
+	default:
+		// terminate all waiting Get()s
+		close(b.upc)
+	}
+
+	b.mu.Unlock()
+	b.wg.Wait()
+
+	// wait for updateNotifyLoop to finish
+	<-b.donec
+	close(b.notifyCh)
+
+	return nil
+}
+
+func grpcHealthCheck(client *Client, ep string) (bool, error) {
+	conn, err := client.dial(ep)
+	if err != nil {
+		return false, err
+	}
+	defer conn.Close()
+	cli := healthpb.NewHealthClient(conn)
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	resp, err := cli.Check(ctx, &healthpb.HealthCheckRequest{})
+	cancel()
+	if err != nil {
+		if s, ok := status.FromError(err); ok && s.Code() == codes.Unavailable {
+			if s.Message() == unknownService { // etcd < v3.3.0
+				return true, nil
+			}
+		}
+		return false, err
+	}
+	return resp.Status == healthpb.HealthCheckResponse_SERVING, nil
+}
+
+func hasAddr(addrs []grpc.Address, targetAddr string) bool {
+	for _, addr := range addrs {
+		if targetAddr == addr.Addr {
+			return true
+		}
+	}
+	return false
+}
+
+func getHost(ep string) string {
+	url, uerr := url.Parse(ep)
+	if uerr != nil || !strings.Contains(ep, "://") {
+		return ep
+	}
+	return url.Host
+}
+
+func eps2addrs(eps []string) []grpc.Address {
+	addrs := make([]grpc.Address, len(eps))
+	for i := range eps {
+		addrs[i].Addr = getHost(eps[i])
+	}
+	return addrs
+}
+
+func getHostPort2ep(eps []string) map[string]string {
+	hm := make(map[string]string, len(eps))
+	for i := range eps {
+		_, host, _ := parseEndpoint(eps[i])
+		hm[host] = eps[i]
+	}
+	return hm
+}