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/auth/store.go b/vendor/github.com/coreos/etcd/auth/store.go
new file mode 100644
index 0000000..d676cb5
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/store.go
@@ -0,0 +1,1136 @@
+// Copyright 2016 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 auth
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"errors"
+	"sort"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"github.com/coreos/etcd/auth/authpb"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"github.com/coreos/etcd/mvcc/backend"
+
+	"github.com/coreos/pkg/capnslog"
+	"golang.org/x/crypto/bcrypt"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+)
+
+var (
+	enableFlagKey = []byte("authEnabled")
+	authEnabled   = []byte{1}
+	authDisabled  = []byte{0}
+
+	revisionKey = []byte("authRevision")
+
+	authBucketName      = []byte("auth")
+	authUsersBucketName = []byte("authUsers")
+	authRolesBucketName = []byte("authRoles")
+
+	plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "auth")
+
+	ErrRootUserNotExist     = errors.New("auth: root user does not exist")
+	ErrRootRoleNotExist     = errors.New("auth: root user does not have root role")
+	ErrUserAlreadyExist     = errors.New("auth: user already exists")
+	ErrUserEmpty            = errors.New("auth: user name is empty")
+	ErrUserNotFound         = errors.New("auth: user not found")
+	ErrRoleAlreadyExist     = errors.New("auth: role already exists")
+	ErrRoleNotFound         = errors.New("auth: role not found")
+	ErrAuthFailed           = errors.New("auth: authentication failed, invalid user ID or password")
+	ErrPermissionDenied     = errors.New("auth: permission denied")
+	ErrRoleNotGranted       = errors.New("auth: role is not granted to the user")
+	ErrPermissionNotGranted = errors.New("auth: permission is not granted to the role")
+	ErrAuthNotEnabled       = errors.New("auth: authentication is not enabled")
+	ErrAuthOldRevision      = errors.New("auth: revision in header is old")
+	ErrInvalidAuthToken     = errors.New("auth: invalid auth token")
+	ErrInvalidAuthOpts      = errors.New("auth: invalid auth options")
+	ErrInvalidAuthMgmt      = errors.New("auth: invalid auth management")
+
+	// BcryptCost is the algorithm cost / strength for hashing auth passwords
+	BcryptCost = bcrypt.DefaultCost
+)
+
+const (
+	rootUser = "root"
+	rootRole = "root"
+
+	tokenTypeSimple = "simple"
+	tokenTypeJWT    = "jwt"
+
+	revBytesLen = 8
+)
+
+type AuthInfo struct {
+	Username string
+	Revision uint64
+}
+
+// AuthenticateParamIndex is used for a key of context in the parameters of Authenticate()
+type AuthenticateParamIndex struct{}
+
+// AuthenticateParamSimpleTokenPrefix is used for a key of context in the parameters of Authenticate()
+type AuthenticateParamSimpleTokenPrefix struct{}
+
+type AuthStore interface {
+	// AuthEnable turns on the authentication feature
+	AuthEnable() error
+
+	// AuthDisable turns off the authentication feature
+	AuthDisable()
+
+	// Authenticate does authentication based on given user name and password
+	Authenticate(ctx context.Context, username, password string) (*pb.AuthenticateResponse, error)
+
+	// Recover recovers the state of auth store from the given backend
+	Recover(b backend.Backend)
+
+	// UserAdd adds a new user
+	UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error)
+
+	// UserDelete deletes a user
+	UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error)
+
+	// UserChangePassword changes a password of a user
+	UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error)
+
+	// UserGrantRole grants a role to the user
+	UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error)
+
+	// UserGet gets the detailed information of a users
+	UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error)
+
+	// UserRevokeRole revokes a role of a user
+	UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error)
+
+	// RoleAdd adds a new role
+	RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error)
+
+	// RoleGrantPermission grants a permission to a role
+	RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error)
+
+	// RoleGet gets the detailed information of a role
+	RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error)
+
+	// RoleRevokePermission gets the detailed information of a role
+	RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error)
+
+	// RoleDelete gets the detailed information of a role
+	RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error)
+
+	// UserList gets a list of all users
+	UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error)
+
+	// RoleList gets a list of all roles
+	RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error)
+
+	// IsPutPermitted checks put permission of the user
+	IsPutPermitted(authInfo *AuthInfo, key []byte) error
+
+	// IsRangePermitted checks range permission of the user
+	IsRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error
+
+	// IsDeleteRangePermitted checks delete-range permission of the user
+	IsDeleteRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error
+
+	// IsAdminPermitted checks admin permission of the user
+	IsAdminPermitted(authInfo *AuthInfo) error
+
+	// GenTokenPrefix produces a random string in a case of simple token
+	// in a case of JWT, it produces an empty string
+	GenTokenPrefix() (string, error)
+
+	// Revision gets current revision of authStore
+	Revision() uint64
+
+	// CheckPassword checks a given pair of username and password is correct
+	CheckPassword(username, password string) (uint64, error)
+
+	// Close does cleanup of AuthStore
+	Close() error
+
+	// AuthInfoFromCtx gets AuthInfo from gRPC's context
+	AuthInfoFromCtx(ctx context.Context) (*AuthInfo, error)
+
+	// AuthInfoFromTLS gets AuthInfo from TLS info of gRPC's context
+	AuthInfoFromTLS(ctx context.Context) *AuthInfo
+
+	// WithRoot generates and installs a token that can be used as a root credential
+	WithRoot(ctx context.Context) context.Context
+
+	// HasRole checks that user has role
+	HasRole(user, role string) bool
+}
+
+type TokenProvider interface {
+	info(ctx context.Context, token string, revision uint64) (*AuthInfo, bool)
+	assign(ctx context.Context, username string, revision uint64) (string, error)
+	enable()
+	disable()
+
+	invalidateUser(string)
+	genTokenPrefix() (string, error)
+}
+
+type authStore struct {
+	// atomic operations; need 64-bit align, or 32-bit tests will crash
+	revision uint64
+
+	be        backend.Backend
+	enabled   bool
+	enabledMu sync.RWMutex
+
+	rangePermCache map[string]*unifiedRangePermissions // username -> unifiedRangePermissions
+
+	tokenProvider TokenProvider
+}
+
+func (as *authStore) AuthEnable() error {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if as.enabled {
+		plog.Noticef("Authentication already enabled")
+		return nil
+	}
+	b := as.be
+	tx := b.BatchTx()
+	tx.Lock()
+	defer func() {
+		tx.Unlock()
+		b.ForceCommit()
+	}()
+
+	u := getUser(tx, rootUser)
+	if u == nil {
+		return ErrRootUserNotExist
+	}
+
+	if !hasRootRole(u) {
+		return ErrRootRoleNotExist
+	}
+
+	tx.UnsafePut(authBucketName, enableFlagKey, authEnabled)
+
+	as.enabled = true
+	as.tokenProvider.enable()
+
+	as.rangePermCache = make(map[string]*unifiedRangePermissions)
+
+	as.setRevision(getRevision(tx))
+
+	plog.Noticef("Authentication enabled")
+
+	return nil
+}
+
+func (as *authStore) AuthDisable() {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if !as.enabled {
+		return
+	}
+	b := as.be
+	tx := b.BatchTx()
+	tx.Lock()
+	tx.UnsafePut(authBucketName, enableFlagKey, authDisabled)
+	as.commitRevision(tx)
+	tx.Unlock()
+	b.ForceCommit()
+
+	as.enabled = false
+	as.tokenProvider.disable()
+
+	plog.Noticef("Authentication disabled")
+}
+
+func (as *authStore) Close() error {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if !as.enabled {
+		return nil
+	}
+	as.tokenProvider.disable()
+	return nil
+}
+
+func (as *authStore) Authenticate(ctx context.Context, username, password string) (*pb.AuthenticateResponse, error) {
+	if !as.isAuthEnabled() {
+		return nil, ErrAuthNotEnabled
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, username)
+	if user == nil {
+		return nil, ErrAuthFailed
+	}
+
+	// Password checking is already performed in the API layer, so we don't need to check for now.
+	// Staleness of password can be detected with OCC in the API layer, too.
+
+	token, err := as.tokenProvider.assign(ctx, username, as.Revision())
+	if err != nil {
+		return nil, err
+	}
+
+	plog.Debugf("authorized %s, token is %s", username, token)
+	return &pb.AuthenticateResponse{Token: token}, nil
+}
+
+func (as *authStore) CheckPassword(username, password string) (uint64, error) {
+	if !as.isAuthEnabled() {
+		return 0, ErrAuthNotEnabled
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, username)
+	if user == nil {
+		return 0, ErrAuthFailed
+	}
+
+	if bcrypt.CompareHashAndPassword(user.Password, []byte(password)) != nil {
+		plog.Noticef("authentication failed, invalid password for user %s", username)
+		return 0, ErrAuthFailed
+	}
+
+	return getRevision(tx), nil
+}
+
+func (as *authStore) Recover(be backend.Backend) {
+	enabled := false
+	as.be = be
+	tx := be.BatchTx()
+	tx.Lock()
+	_, vs := tx.UnsafeRange(authBucketName, enableFlagKey, nil, 0)
+	if len(vs) == 1 {
+		if bytes.Equal(vs[0], authEnabled) {
+			enabled = true
+		}
+	}
+
+	as.setRevision(getRevision(tx))
+
+	tx.Unlock()
+
+	as.enabledMu.Lock()
+	as.enabled = enabled
+	as.enabledMu.Unlock()
+}
+
+func (as *authStore) UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	if len(r.Name) == 0 {
+		return nil, ErrUserEmpty
+	}
+
+	hashed, err := bcrypt.GenerateFromPassword([]byte(r.Password), BcryptCost)
+	if err != nil {
+		plog.Errorf("failed to hash password: %s", err)
+		return nil, err
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user != nil {
+		return nil, ErrUserAlreadyExist
+	}
+
+	newUser := &authpb.User{
+		Name:     []byte(r.Name),
+		Password: hashed,
+	}
+
+	putUser(tx, newUser)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("added a new user: %s", r.Name)
+
+	return &pb.AuthUserAddResponse{}, nil
+}
+
+func (as *authStore) UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error) {
+	if as.enabled && strings.Compare(r.Name, rootUser) == 0 {
+		plog.Errorf("the user root must not be deleted")
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	delUser(tx, r.Name)
+
+	as.commitRevision(tx)
+
+	as.invalidateCachedPerm(r.Name)
+	as.tokenProvider.invalidateUser(r.Name)
+
+	plog.Noticef("deleted a user: %s", r.Name)
+
+	return &pb.AuthUserDeleteResponse{}, nil
+}
+
+func (as *authStore) UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error) {
+	// TODO(mitake): measure the cost of bcrypt.GenerateFromPassword()
+	// If the cost is too high, we should move the encryption to outside of the raft
+	hashed, err := bcrypt.GenerateFromPassword([]byte(r.Password), BcryptCost)
+	if err != nil {
+		plog.Errorf("failed to hash password: %s", err)
+		return nil, err
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	updatedUser := &authpb.User{
+		Name:     []byte(r.Name),
+		Roles:    user.Roles,
+		Password: hashed,
+	}
+
+	putUser(tx, updatedUser)
+
+	as.commitRevision(tx)
+
+	as.invalidateCachedPerm(r.Name)
+	as.tokenProvider.invalidateUser(r.Name)
+
+	plog.Noticef("changed a password of a user: %s", r.Name)
+
+	return &pb.AuthUserChangePasswordResponse{}, nil
+}
+
+func (as *authStore) UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.User)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	if r.Role != rootRole {
+		role := getRole(tx, r.Role)
+		if role == nil {
+			return nil, ErrRoleNotFound
+		}
+	}
+
+	idx := sort.SearchStrings(user.Roles, r.Role)
+	if idx < len(user.Roles) && strings.Compare(user.Roles[idx], r.Role) == 0 {
+		plog.Warningf("user %s is already granted role %s", r.User, r.Role)
+		return &pb.AuthUserGrantRoleResponse{}, nil
+	}
+
+	user.Roles = append(user.Roles, r.Role)
+	sort.Strings(user.Roles)
+
+	putUser(tx, user)
+
+	as.invalidateCachedPerm(r.User)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("granted role %s to user %s", r.Role, r.User)
+	return &pb.AuthUserGrantRoleResponse{}, nil
+}
+
+func (as *authStore) UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	user := getUser(tx, r.Name)
+	tx.Unlock()
+
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	var resp pb.AuthUserGetResponse
+	resp.Roles = append(resp.Roles, user.Roles...)
+	return &resp, nil
+}
+
+func (as *authStore) UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	users := getAllUsers(tx)
+	tx.Unlock()
+
+	resp := &pb.AuthUserListResponse{Users: make([]string, len(users))}
+	for i := range users {
+		resp.Users[i] = string(users[i].Name)
+	}
+	return resp, nil
+}
+
+func (as *authStore) UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error) {
+	if as.enabled && strings.Compare(r.Name, rootUser) == 0 && strings.Compare(r.Role, rootRole) == 0 {
+		plog.Errorf("the role root must not be revoked from the user root")
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	updatedUser := &authpb.User{
+		Name:     user.Name,
+		Password: user.Password,
+	}
+
+	for _, role := range user.Roles {
+		if strings.Compare(role, r.Role) != 0 {
+			updatedUser.Roles = append(updatedUser.Roles, role)
+		}
+	}
+
+	if len(updatedUser.Roles) == len(user.Roles) {
+		return nil, ErrRoleNotGranted
+	}
+
+	putUser(tx, updatedUser)
+
+	as.invalidateCachedPerm(r.Name)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("revoked role %s from user %s", r.Role, r.Name)
+	return &pb.AuthUserRevokeRoleResponse{}, nil
+}
+
+func (as *authStore) RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	var resp pb.AuthRoleGetResponse
+
+	role := getRole(tx, r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+	resp.Perm = append(resp.Perm, role.KeyPermission...)
+	return &resp, nil
+}
+
+func (as *authStore) RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	roles := getAllRoles(tx)
+	tx.Unlock()
+
+	resp := &pb.AuthRoleListResponse{Roles: make([]string, len(roles))}
+	for i := range roles {
+		resp.Roles[i] = string(roles[i].Name)
+	}
+	return resp, nil
+}
+
+func (as *authStore) RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	updatedRole := &authpb.Role{
+		Name: role.Name,
+	}
+
+	for _, perm := range role.KeyPermission {
+		if !bytes.Equal(perm.Key, []byte(r.Key)) || !bytes.Equal(perm.RangeEnd, []byte(r.RangeEnd)) {
+			updatedRole.KeyPermission = append(updatedRole.KeyPermission, perm)
+		}
+	}
+
+	if len(role.KeyPermission) == len(updatedRole.KeyPermission) {
+		return nil, ErrPermissionNotGranted
+	}
+
+	putRole(tx, updatedRole)
+
+	// TODO(mitake): currently single role update invalidates every cache
+	// It should be optimized.
+	as.clearCachedPerm()
+
+	as.commitRevision(tx)
+
+	plog.Noticef("revoked key %s from role %s", r.Key, r.Role)
+	return &pb.AuthRoleRevokePermissionResponse{}, nil
+}
+
+func (as *authStore) RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error) {
+	if as.enabled && strings.Compare(r.Role, rootRole) == 0 {
+		plog.Errorf("the role root must not be deleted")
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	delRole(tx, r.Role)
+
+	users := getAllUsers(tx)
+	for _, user := range users {
+		updatedUser := &authpb.User{
+			Name:     user.Name,
+			Password: user.Password,
+		}
+
+		for _, role := range user.Roles {
+			if strings.Compare(role, r.Role) != 0 {
+				updatedUser.Roles = append(updatedUser.Roles, role)
+			}
+		}
+
+		if len(updatedUser.Roles) == len(user.Roles) {
+			continue
+		}
+
+		putUser(tx, updatedUser)
+
+		as.invalidateCachedPerm(string(user.Name))
+	}
+
+	as.commitRevision(tx)
+
+	plog.Noticef("deleted role %s", r.Role)
+	return &pb.AuthRoleDeleteResponse{}, nil
+}
+
+func (as *authStore) RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Name)
+	if role != nil {
+		return nil, ErrRoleAlreadyExist
+	}
+
+	newRole := &authpb.Role{
+		Name: []byte(r.Name),
+	}
+
+	putRole(tx, newRole)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("Role %s is created", r.Name)
+
+	return &pb.AuthRoleAddResponse{}, nil
+}
+
+func (as *authStore) authInfoFromToken(ctx context.Context, token string) (*AuthInfo, bool) {
+	return as.tokenProvider.info(ctx, token, as.Revision())
+}
+
+type permSlice []*authpb.Permission
+
+func (perms permSlice) Len() int {
+	return len(perms)
+}
+
+func (perms permSlice) Less(i, j int) bool {
+	return bytes.Compare(perms[i].Key, perms[j].Key) < 0
+}
+
+func (perms permSlice) Swap(i, j int) {
+	perms[i], perms[j] = perms[j], perms[i]
+}
+
+func (as *authStore) RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Name)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	idx := sort.Search(len(role.KeyPermission), func(i int) bool {
+		return bytes.Compare(role.KeyPermission[i].Key, []byte(r.Perm.Key)) >= 0
+	})
+
+	if idx < len(role.KeyPermission) && bytes.Equal(role.KeyPermission[idx].Key, r.Perm.Key) && bytes.Equal(role.KeyPermission[idx].RangeEnd, r.Perm.RangeEnd) {
+		// update existing permission
+		role.KeyPermission[idx].PermType = r.Perm.PermType
+	} else {
+		// append new permission to the role
+		newPerm := &authpb.Permission{
+			Key:      []byte(r.Perm.Key),
+			RangeEnd: []byte(r.Perm.RangeEnd),
+			PermType: r.Perm.PermType,
+		}
+
+		role.KeyPermission = append(role.KeyPermission, newPerm)
+		sort.Sort(permSlice(role.KeyPermission))
+	}
+
+	putRole(tx, role)
+
+	// TODO(mitake): currently single role update invalidates every cache
+	// It should be optimized.
+	as.clearCachedPerm()
+
+	as.commitRevision(tx)
+
+	plog.Noticef("role %s's permission of key %s is updated as %s", r.Name, r.Perm.Key, authpb.Permission_Type_name[int32(r.Perm.PermType)])
+
+	return &pb.AuthRoleGrantPermissionResponse{}, nil
+}
+
+func (as *authStore) isOpPermitted(userName string, revision uint64, key, rangeEnd []byte, permTyp authpb.Permission_Type) error {
+	// TODO(mitake): this function would be costly so we need a caching mechanism
+	if !as.isAuthEnabled() {
+		return nil
+	}
+
+	// only gets rev == 0 when passed AuthInfo{}; no user given
+	if revision == 0 {
+		return ErrUserEmpty
+	}
+
+	if revision < as.Revision() {
+		return ErrAuthOldRevision
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, userName)
+	if user == nil {
+		plog.Errorf("invalid user name %s for permission checking", userName)
+		return ErrPermissionDenied
+	}
+
+	// root role should have permission on all ranges
+	if hasRootRole(user) {
+		return nil
+	}
+
+	if as.isRangeOpPermitted(tx, userName, key, rangeEnd, permTyp) {
+		return nil
+	}
+
+	return ErrPermissionDenied
+}
+
+func (as *authStore) IsPutPermitted(authInfo *AuthInfo, key []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, nil, authpb.WRITE)
+}
+
+func (as *authStore) IsRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, rangeEnd, authpb.READ)
+}
+
+func (as *authStore) IsDeleteRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, rangeEnd, authpb.WRITE)
+}
+
+func (as *authStore) IsAdminPermitted(authInfo *AuthInfo) error {
+	if !as.isAuthEnabled() {
+		return nil
+	}
+	if authInfo == nil {
+		return ErrUserEmpty
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	u := getUser(tx, authInfo.Username)
+	tx.Unlock()
+
+	if u == nil {
+		return ErrUserNotFound
+	}
+
+	if !hasRootRole(u) {
+		return ErrPermissionDenied
+	}
+
+	return nil
+}
+
+func getUser(tx backend.BatchTx, username string) *authpb.User {
+	_, vs := tx.UnsafeRange(authUsersBucketName, []byte(username), nil, 0)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	user := &authpb.User{}
+	err := user.Unmarshal(vs[0])
+	if err != nil {
+		plog.Panicf("failed to unmarshal user struct (name: %s): %s", username, err)
+	}
+	return user
+}
+
+func getAllUsers(tx backend.BatchTx) []*authpb.User {
+	_, vs := tx.UnsafeRange(authUsersBucketName, []byte{0}, []byte{0xff}, -1)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	users := make([]*authpb.User, len(vs))
+	for i := range vs {
+		user := &authpb.User{}
+		err := user.Unmarshal(vs[i])
+		if err != nil {
+			plog.Panicf("failed to unmarshal user struct: %s", err)
+		}
+		users[i] = user
+	}
+	return users
+}
+
+func putUser(tx backend.BatchTx, user *authpb.User) {
+	b, err := user.Marshal()
+	if err != nil {
+		plog.Panicf("failed to marshal user struct (name: %s): %s", user.Name, err)
+	}
+	tx.UnsafePut(authUsersBucketName, user.Name, b)
+}
+
+func delUser(tx backend.BatchTx, username string) {
+	tx.UnsafeDelete(authUsersBucketName, []byte(username))
+}
+
+func getRole(tx backend.BatchTx, rolename string) *authpb.Role {
+	_, vs := tx.UnsafeRange(authRolesBucketName, []byte(rolename), nil, 0)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	role := &authpb.Role{}
+	err := role.Unmarshal(vs[0])
+	if err != nil {
+		plog.Panicf("failed to unmarshal role struct (name: %s): %s", rolename, err)
+	}
+	return role
+}
+
+func getAllRoles(tx backend.BatchTx) []*authpb.Role {
+	_, vs := tx.UnsafeRange(authRolesBucketName, []byte{0}, []byte{0xff}, -1)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	roles := make([]*authpb.Role, len(vs))
+	for i := range vs {
+		role := &authpb.Role{}
+		err := role.Unmarshal(vs[i])
+		if err != nil {
+			plog.Panicf("failed to unmarshal role struct: %s", err)
+		}
+		roles[i] = role
+	}
+	return roles
+}
+
+func putRole(tx backend.BatchTx, role *authpb.Role) {
+	b, err := role.Marshal()
+	if err != nil {
+		plog.Panicf("failed to marshal role struct (name: %s): %s", role.Name, err)
+	}
+
+	tx.UnsafePut(authRolesBucketName, []byte(role.Name), b)
+}
+
+func delRole(tx backend.BatchTx, rolename string) {
+	tx.UnsafeDelete(authRolesBucketName, []byte(rolename))
+}
+
+func (as *authStore) isAuthEnabled() bool {
+	as.enabledMu.RLock()
+	defer as.enabledMu.RUnlock()
+	return as.enabled
+}
+
+func NewAuthStore(be backend.Backend, tp TokenProvider) *authStore {
+	tx := be.BatchTx()
+	tx.Lock()
+
+	tx.UnsafeCreateBucket(authBucketName)
+	tx.UnsafeCreateBucket(authUsersBucketName)
+	tx.UnsafeCreateBucket(authRolesBucketName)
+
+	enabled := false
+	_, vs := tx.UnsafeRange(authBucketName, enableFlagKey, nil, 0)
+	if len(vs) == 1 {
+		if bytes.Equal(vs[0], authEnabled) {
+			enabled = true
+		}
+	}
+
+	as := &authStore{
+		be:             be,
+		revision:       getRevision(tx),
+		enabled:        enabled,
+		rangePermCache: make(map[string]*unifiedRangePermissions),
+		tokenProvider:  tp,
+	}
+
+	if enabled {
+		as.tokenProvider.enable()
+	}
+
+	if as.Revision() == 0 {
+		as.commitRevision(tx)
+	}
+
+	tx.Unlock()
+	be.ForceCommit()
+
+	return as
+}
+
+func hasRootRole(u *authpb.User) bool {
+	// u.Roles is sorted in UserGrantRole(), so we can use binary search.
+	idx := sort.SearchStrings(u.Roles, rootRole)
+	return idx != len(u.Roles) && u.Roles[idx] == rootRole
+}
+
+func (as *authStore) commitRevision(tx backend.BatchTx) {
+	atomic.AddUint64(&as.revision, 1)
+	revBytes := make([]byte, revBytesLen)
+	binary.BigEndian.PutUint64(revBytes, as.Revision())
+	tx.UnsafePut(authBucketName, revisionKey, revBytes)
+}
+
+func getRevision(tx backend.BatchTx) uint64 {
+	_, vs := tx.UnsafeRange(authBucketName, []byte(revisionKey), nil, 0)
+	if len(vs) != 1 {
+		// this can happen in the initialization phase
+		return 0
+	}
+
+	return binary.BigEndian.Uint64(vs[0])
+}
+
+func (as *authStore) setRevision(rev uint64) {
+	atomic.StoreUint64(&as.revision, rev)
+}
+
+func (as *authStore) Revision() uint64 {
+	return atomic.LoadUint64(&as.revision)
+}
+
+func (as *authStore) AuthInfoFromTLS(ctx context.Context) *AuthInfo {
+	peer, ok := peer.FromContext(ctx)
+	if !ok || peer == nil || peer.AuthInfo == nil {
+		return nil
+	}
+
+	tlsInfo := peer.AuthInfo.(credentials.TLSInfo)
+	for _, chains := range tlsInfo.State.VerifiedChains {
+		for _, chain := range chains {
+			cn := chain.Subject.CommonName
+			plog.Debugf("found common name %s", cn)
+
+			ai := &AuthInfo{
+				Username: cn,
+				Revision: as.Revision(),
+			}
+			md, ok := metadata.FromIncomingContext(ctx)
+			if !ok {
+				return nil
+			}
+
+			// gRPC-gateway proxy request to etcd server includes Grpcgateway-Accept
+			// header. The proxy uses etcd client server certificate. If the certificate
+			// has a CommonName we should never use this for authentication.
+			if gw := md["grpcgateway-accept"]; len(gw) > 0 {
+				plog.Warningf("ignoring common name in gRPC-gateway proxy request %s", ai.Username)
+				return nil
+			}
+			return ai
+		}
+	}
+
+	return nil
+}
+
+func (as *authStore) AuthInfoFromCtx(ctx context.Context) (*AuthInfo, error) {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, nil
+	}
+
+	//TODO(mitake|hexfusion) review unifying key names
+	ts, ok := md["token"]
+	if !ok {
+		ts, ok = md["authorization"]
+	}
+	if !ok {
+		return nil, nil
+	}
+
+	token := ts[0]
+	authInfo, uok := as.authInfoFromToken(ctx, token)
+	if !uok {
+		plog.Warningf("invalid auth token: %s", token)
+		return nil, ErrInvalidAuthToken
+	}
+
+	return authInfo, nil
+}
+
+func (as *authStore) GenTokenPrefix() (string, error) {
+	return as.tokenProvider.genTokenPrefix()
+}
+
+func decomposeOpts(optstr string) (string, map[string]string, error) {
+	opts := strings.Split(optstr, ",")
+	tokenType := opts[0]
+
+	typeSpecificOpts := make(map[string]string)
+	for i := 1; i < len(opts); i++ {
+		pair := strings.Split(opts[i], "=")
+
+		if len(pair) != 2 {
+			plog.Errorf("invalid token specific option: %s", optstr)
+			return "", nil, ErrInvalidAuthOpts
+		}
+
+		if _, ok := typeSpecificOpts[pair[0]]; ok {
+			plog.Errorf("invalid token specific option, duplicated parameters (%s): %s", pair[0], optstr)
+			return "", nil, ErrInvalidAuthOpts
+		}
+
+		typeSpecificOpts[pair[0]] = pair[1]
+	}
+
+	return tokenType, typeSpecificOpts, nil
+
+}
+
+func NewTokenProvider(tokenOpts string, indexWaiter func(uint64) <-chan struct{}) (TokenProvider, error) {
+	tokenType, typeSpecificOpts, err := decomposeOpts(tokenOpts)
+	if err != nil {
+		return nil, ErrInvalidAuthOpts
+	}
+
+	switch tokenType {
+	case tokenTypeSimple:
+		plog.Warningf("simple token is not cryptographically signed")
+		return newTokenProviderSimple(indexWaiter), nil
+
+	case tokenTypeJWT:
+		return newTokenProviderJWT(typeSpecificOpts)
+
+	case "":
+		return newTokenProviderNop()
+	default:
+		plog.Errorf("unknown token type: %s", tokenType)
+		return nil, ErrInvalidAuthOpts
+	}
+}
+
+func (as *authStore) WithRoot(ctx context.Context) context.Context {
+	if !as.isAuthEnabled() {
+		return ctx
+	}
+
+	var ctxForAssign context.Context
+	if ts, ok := as.tokenProvider.(*tokenSimple); ok && ts != nil {
+		ctx1 := context.WithValue(ctx, AuthenticateParamIndex{}, uint64(0))
+		prefix, err := ts.genTokenPrefix()
+		if err != nil {
+			plog.Errorf("failed to generate prefix of internally used token")
+			return ctx
+		}
+		ctxForAssign = context.WithValue(ctx1, AuthenticateParamSimpleTokenPrefix{}, prefix)
+	} else {
+		ctxForAssign = ctx
+	}
+
+	token, err := as.tokenProvider.assign(ctxForAssign, "root", as.Revision())
+	if err != nil {
+		// this must not happen
+		plog.Errorf("failed to assign token for lease revoking: %s", err)
+		return ctx
+	}
+
+	mdMap := map[string]string{
+		"token": token,
+	}
+	tokenMD := metadata.New(mdMap)
+
+	// use "mdIncomingKey{}" since it's called from local etcdserver
+	return metadata.NewIncomingContext(ctx, tokenMD)
+}
+
+func (as *authStore) HasRole(user, role string) bool {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	u := getUser(tx, user)
+	tx.Unlock()
+
+	if u == nil {
+		plog.Warningf("tried to check user %s has role %s, but user %s doesn't exist", user, role, user)
+		return false
+	}
+
+	for _, r := range u.Roles {
+		if role == r {
+			return true
+		}
+	}
+
+	return false
+}