Add long-running client session endpoint

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

api/server/backend/build/backend.go

@@ -27,9 +27,9 @@ type Backend struct {
 }
 
 // NewBackend creates a new build backend from components
-func NewBackend(components ImageComponent, builderBackend builder.Backend, idMappings *idtools.IDMappings) *Backend {
-	manager := dockerfile.NewBuildManager(builderBackend, idMappings)
-	return &Backend{imageComponent: components, manager: manager}
+func NewBackend(components ImageComponent, builderBackend builder.Backend, sg dockerfile.SessionGetter, idMappings *idtools.IDMappings) (*Backend, error) {
+	manager := dockerfile.NewBuildManager(builderBackend, sg, idMappings)
+	return &Backend{imageComponent: components, manager: manager}, nil
 }
 
 // Build builds an image from a Source

api/server/router/build/build_routes.go

@@ -127,6 +127,7 @@ func newImageBuildOptions(ctx context.Context, r *http.Request) (*types.ImageBui
 		}
 		options.CacheFrom = cacheFrom
 	}
+	options.SessionID = r.FormValue("session")
 
 	return options, nil
 }

api/server/router/session/backend.go

@@ -0,0 +1,12 @@
+package session
+
+import (
+	"net/http"
+
+	"golang.org/x/net/context"
+)
+
+// Backend abstracts an session receiver from an http request.
+type Backend interface {
+	HandleHTTPRequest(ctx context.Context, w http.ResponseWriter, r *http.Request) error
+}

api/server/router/session/session.go

@@ -0,0 +1,29 @@
+package session
+
+import "github.com/docker/docker/api/server/router"
+
+// sessionRouter is a router to talk with the session controller
+type sessionRouter struct {
+	backend Backend
+	routes  []router.Route
+}
+
+// NewRouter initializes a new session router
+func NewRouter(b Backend) router.Router {
+	r := &sessionRouter{
+		backend: b,
+	}
+	r.initRoutes()
+	return r
+}
+
+// Routes returns the available routers to the session controller
+func (r *sessionRouter) Routes() []router.Route {
+	return r.routes
+}
+
+func (r *sessionRouter) initRoutes() {
+	r.routes = []router.Route{
+		router.Experimental(router.NewPostRoute("/session", r.startSession)),
+	}
+}

api/server/router/session/session_routes.go

@@ -0,0 +1,16 @@
+package session
+
+import (
+	"net/http"
+
+	apierrors "github.com/docker/docker/api/errors"
+	"golang.org/x/net/context"
+)
+
+func (sr *sessionRouter) startSession(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
+	err := sr.backend.HandleHTTPRequest(ctx, w, r)
+	if err != nil {
+		return apierrors.NewBadRequestError(err)
+	}
+	return nil
+}

api/types/client.go

@@ -7,7 +7,7 @@ import (
 
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/filters"
-	"github.com/docker/go-units"
+	units "github.com/docker/go-units"
 )
 
 // CheckpointCreateOptions holds parameters to create a checkpoint from a container
@@ -178,6 +178,7 @@ type ImageBuildOptions struct {
 	SecurityOpt []string
 	ExtraHosts  []string // List of extra hosts
 	Target      string
+	SessionID   string
 
 	// TODO @jhowardmsft LCOW Support: This will require extending to include
 	// `Platform string`, but is ommited for now as it's hard-coded temporarily

builder/dockerfile/builder.go

@@ -16,6 +16,7 @@ import (
 	"github.com/docker/docker/builder/dockerfile/command"
 	"github.com/docker/docker/builder/dockerfile/parser"
 	"github.com/docker/docker/builder/remotecontext"
+	"github.com/docker/docker/client/session"
 	"github.com/docker/docker/pkg/archive"
 	"github.com/docker/docker/pkg/chrootarchive"
 	"github.com/docker/docker/pkg/idtools"
@@ -40,18 +41,25 @@ var validCommitCommands = map[string]bool{
 	"workdir":     true,
 }
 
+// SessionGetter is object used to get access to a session by uuid
+type SessionGetter interface {
+	Get(ctx context.Context, uuid string) (session.Caller, error)
+}
+
 // BuildManager is shared across all Builder objects
 type BuildManager struct {
 	archiver  *archive.Archiver
 	backend   builder.Backend
 	pathCache pathCache // TODO: make this persistent
+	sg        SessionGetter
 }
 
 // NewBuildManager creates a BuildManager
-func NewBuildManager(b builder.Backend, idMappings *idtools.IDMappings) *BuildManager {
+func NewBuildManager(b builder.Backend, sg SessionGetter, idMappings *idtools.IDMappings) *BuildManager {
 	return &BuildManager{
 		backend:   b,
 		pathCache: &syncmap.Map{},
+		sg:        sg,
 		archiver:  chrootarchive.NewArchiver(idMappings),
 	}
 }
@@ -84,6 +92,13 @@ func (bm *BuildManager) Build(ctx context.Context, config backend.BuildConfig) (
 		}
 	}
 
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	if err := bm.initializeClientSession(ctx, cancel, config.Options); err != nil {
+		return nil, err
+	}
+
 	builderOptions := builderOptions{
 		Options:        config.Options,
 		ProgressWriter: config.ProgressWriter,
@@ -96,6 +111,22 @@ func (bm *BuildManager) Build(ctx context.Context, config backend.BuildConfig) (
 	return newBuilder(ctx, builderOptions).build(source, dockerfile)
 }
 
+func (bm *BuildManager) initializeClientSession(ctx context.Context, cancel func(), options *types.ImageBuildOptions) error {
+	if options.SessionID == "" || bm.sg == nil {
+		return nil
+	}
+	logrus.Debug("client is session enabled")
+	c, err := bm.sg.Get(ctx, options.SessionID)
+	if err != nil {
+		return err
+	}
+	go func() {
+		<-c.Context().Done()
+		cancel()
+	}()
+	return nil
+}
+
 // builderOptions are the dependencies required by the builder
 type builderOptions struct {
 	Options        *types.ImageBuildOptions

client/hijack.go

@@ -1,11 +1,9 @@
 package client
 
 import (
-	"bytes"
+	"bufio"
 	"crypto/tls"
-	"errors"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httputil"
@@ -16,6 +14,7 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/pkg/tlsconfig"
 	"github.com/docker/go-connections/sockets"
+	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 )
 
@@ -48,49 +47,12 @@ func (cli *Client) postHijacked(ctx context.Context, path string, query url.Valu
 	}
 	req = cli.addHeaders(req, headers)
 
-	req.Host = cli.addr
-	req.Header.Set("Connection", "Upgrade")
-	req.Header.Set("Upgrade", "tcp")
-
-	conn, err := dial(cli.proto, cli.addr, resolveTLSConfig(cli.client.Transport))
+	conn, err := cli.setupHijackConn(req, "tcp")
 	if err != nil {
-		if strings.Contains(err.Error(), "connection refused") {
-			return types.HijackedResponse{}, fmt.Errorf("Cannot connect to the Docker daemon. Is 'docker daemon' running on this host?")
-		}
 		return types.HijackedResponse{}, err
 	}
 
-	// When we set up a TCP connection for hijack, there could be long periods
-	// of inactivity (a long running command with no output) that in certain
-	// network setups may cause ECONNTIMEOUT, leaving the client in an unknown
-	// state. Setting TCP KeepAlive on the socket connection will prohibit
-	// ECONNTIMEOUT unless the socket connection truly is broken
-	if tcpConn, ok := conn.(*net.TCPConn); ok {
-		tcpConn.SetKeepAlive(true)
-		tcpConn.SetKeepAlivePeriod(30 * time.Second)
-	}
-
-	clientconn := httputil.NewClientConn(conn, nil)
-	defer clientconn.Close()
-
-	// Server hijacks the connection, error 'connection closed' expected
-	resp, err := clientconn.Do(req)
-	if err != nil {
-		return types.HijackedResponse{}, err
-	}
-
-	defer resp.Body.Close()
-	switch resp.StatusCode {
-	case http.StatusOK, http.StatusSwitchingProtocols:
-		rwc, br := clientconn.Hijack()
-		return types.HijackedResponse{Conn: rwc, Reader: br}, err
-	}
-
-	errbody, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		return types.HijackedResponse{}, err
-	}
-	return types.HijackedResponse{}, fmt.Errorf("Error response from daemon: %s", bytes.TrimSpace(errbody))
+	return types.HijackedResponse{Conn: conn, Reader: bufio.NewReader(conn)}, err
 }
 
 func tlsDial(network, addr string, config *tls.Config) (net.Conn, error) {
@@ -189,3 +151,56 @@ func dial(proto, addr string, tlsConfig *tls.Config) (net.Conn, error) {
 	}
 	return net.Dial(proto, addr)
 }
+
+func (cli *Client) setupHijackConn(req *http.Request, proto string) (net.Conn, error) {
+	req.Host = cli.addr
+	req.Header.Set("Connection", "Upgrade")
+	req.Header.Set("Upgrade", proto)
+
+	conn, err := dial(cli.proto, cli.addr, resolveTLSConfig(cli.client.Transport))
+	if err != nil {
+		return nil, errors.Wrap(err, "cannot connect to the Docker daemon. Is 'docker daemon' running on this host?")
+	}
+
+	// When we set up a TCP connection for hijack, there could be long periods
+	// of inactivity (a long running command with no output) that in certain
+	// network setups may cause ECONNTIMEOUT, leaving the client in an unknown
+	// state. Setting TCP KeepAlive on the socket connection will prohibit
+	// ECONNTIMEOUT unless the socket connection truly is broken
+	if tcpConn, ok := conn.(*net.TCPConn); ok {
+		tcpConn.SetKeepAlive(true)
+		tcpConn.SetKeepAlivePeriod(30 * time.Second)
+	}
+
+	clientconn := httputil.NewClientConn(conn, nil)
+	defer clientconn.Close()
+
+	// Server hijacks the connection, error 'connection closed' expected
+	resp, err := clientconn.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != http.StatusSwitchingProtocols {
+		resp.Body.Close()
+		return nil, fmt.Errorf("unable to upgrade to %s, received %d", proto, resp.StatusCode)
+	}
+
+	c, br := clientconn.Hijack()
+	if br.Buffered() > 0 {
+		// If there is buffered content, wrap the connection
+		c = &hijackedConn{c, br}
+	} else {
+		br.Reset(nil)
+	}
+
+	return c, nil
+}
+
+type hijackedConn struct {
+	net.Conn
+	r *bufio.Reader
+}
+
+func (c *hijackedConn) Read(b []byte) (int, error) {
+	return c.r.Read(b)
+}

client/image_build.go

@@ -120,6 +120,9 @@ func (cli *Client) imageBuildOptionsToQuery(options types.ImageBuildOptions) (ur
 		return query, err
 	}
 	query.Set("cachefrom", string(cacheFromJSON))
+	if options.SessionID != "" {
+		query.Set("session", options.SessionID)
+	}
 
 	return query, nil
 }

client/interface.go

@@ -2,6 +2,7 @@ package client
 
 import (
 	"io"
+	"net"
 	"time"
 
 	"github.com/docker/docker/api/types"
@@ -35,6 +36,7 @@ type CommonAPIClient interface {
 	ServerVersion(ctx context.Context) (types.Version, error)
 	NegotiateAPIVersion(ctx context.Context)
 	NegotiateAPIVersionPing(types.Ping)
+	DialSession(ctx context.Context, proto string, meta map[string][]string) (net.Conn, error)
 }
 
 // ContainerAPIClient defines API client methods for the containers

client/session.go

@@ -0,0 +1,19 @@
+package client
+
+import (
+	"net"
+	"net/http"
+
+	"golang.org/x/net/context"
+)
+
+// DialSession returns a connection that can be used communication with daemon
+func (cli *Client) DialSession(ctx context.Context, proto string, meta map[string][]string) (net.Conn, error) {
+	req, err := http.NewRequest("POST", "/session", nil)
+	if err != nil {
+		return nil, err
+	}
+	req = cli.addHeaders(req, meta)
+
+	return cli.setupHijackConn(req, proto)
+}

client/session/grpc.go

@@ -0,0 +1,62 @@
+package session
+
+import (
+	"net"
+	"time"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/pkg/errors"
+	"golang.org/x/net/context"
+	"golang.org/x/net/http2"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/health/grpc_health_v1"
+)
+
+func serve(ctx context.Context, grpcServer *grpc.Server, conn net.Conn) {
+	go func() {
+		<-ctx.Done()
+		conn.Close()
+	}()
+	logrus.Debugf("serving grpc connection")
+	(&http2.Server{}).ServeConn(conn, &http2.ServeConnOpts{Handler: grpcServer})
+}
+
+func grpcClientConn(ctx context.Context, conn net.Conn) (context.Context, *grpc.ClientConn, error) {
+	dialOpt := grpc.WithDialer(func(addr string, d time.Duration) (net.Conn, error) {
+		return conn, nil
+	})
+
+	cc, err := grpc.DialContext(ctx, "", dialOpt, grpc.WithInsecure())
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "failed to create grpc client")
+	}
+
+	ctx, cancel := context.WithCancel(ctx)
+	go monitorHealth(ctx, cc, cancel)
+
+	return ctx, cc, nil
+}
+
+func monitorHealth(ctx context.Context, cc *grpc.ClientConn, cancelConn func()) {
+	defer cancelConn()
+	defer cc.Close()
+
+	ticker := time.NewTicker(500 * time.Millisecond)
+	defer ticker.Stop()
+	healthClient := grpc_health_v1.NewHealthClient(cc)
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			<-ticker.C
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			_, err := healthClient.Check(ctx, &grpc_health_v1.HealthCheckRequest{})
+			cancel()
+			if err != nil {
+				return
+			}
+		}
+	}
+}

client/session/manager.go

@@ -0,0 +1,187 @@
+package session
+
+import (
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/pkg/errors"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+)
+
+// Caller can invoke requests on the session
+type Caller interface {
+	Context() context.Context
+	Supports(method string) bool
+	Conn() *grpc.ClientConn
+	Name() string
+	SharedKey() string
+}
+
+type client struct {
+	Session
+	cc        *grpc.ClientConn
+	supported map[string]struct{}
+}
+
+// Manager is a controller for accessing currently active sessions
+type Manager struct {
+	sessions        map[string]*client
+	mu              sync.Mutex
+	updateCondition *sync.Cond
+}
+
+// NewManager returns a new Manager
+func NewManager() (*Manager, error) {
+	sm := &Manager{
+		sessions: make(map[string]*client),
+	}
+	sm.updateCondition = sync.NewCond(&sm.mu)
+	return sm, nil
+}
+
+// HandleHTTPRequest handles an incoming HTTP request
+func (sm *Manager) HandleHTTPRequest(ctx context.Context, w http.ResponseWriter, r *http.Request) error {
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		return errors.New("handler does not support hijack")
+	}
+
+	uuid := r.Header.Get(headerSessionUUID)
+	name := r.Header.Get(headerSessionName)
+	sharedKey := r.Header.Get(headerSessionSharedKey)
+
+	proto := r.Header.Get("Upgrade")
+
+	sm.mu.Lock()
+	if _, ok := sm.sessions[uuid]; ok {
+		sm.mu.Unlock()
+		return errors.Errorf("session %s already exists", uuid)
+	}
+
+	if proto == "" {
+		sm.mu.Unlock()
+		return errors.New("no upgrade proto in request")
+	}
+
+	if proto != "h2c" {
+		sm.mu.Unlock()
+		return errors.Errorf("protocol %s not supported", proto)
+	}
+
+	conn, _, err := hijacker.Hijack()
+	if err != nil {
+		sm.mu.Unlock()
+		return errors.Wrap(err, "failed to hijack connection")
+	}
+
+	resp := &http.Response{
+		StatusCode: http.StatusSwitchingProtocols,
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+		Header:     http.Header{},
+	}
+	resp.Header.Set("Connection", "Upgrade")
+	resp.Header.Set("Upgrade", proto)
+
+	// set raw mode
+	conn.Write([]byte{})
+	resp.Write(conn)
+
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	ctx, cc, err := grpcClientConn(ctx, conn)
+	if err != nil {
+		sm.mu.Unlock()
+		return err
+	}
+
+	c := &client{
+		Session: Session{
+			uuid:      uuid,
+			name:      name,
+			sharedKey: sharedKey,
+			ctx:       ctx,
+			cancelCtx: cancel,
+			done:      make(chan struct{}),
+		},
+		cc:        cc,
+		supported: make(map[string]struct{}),
+	}
+
+	for _, m := range r.Header[headerSessionMethod] {
+		c.supported[strings.ToLower(m)] = struct{}{}
+	}
+	sm.sessions[uuid] = c
+	sm.updateCondition.Broadcast()
+	sm.mu.Unlock()
+
+	defer func() {
+		sm.mu.Lock()
+		delete(sm.sessions, uuid)
+		sm.mu.Unlock()
+	}()
+
+	<-c.ctx.Done()
+	conn.Close()
+	close(c.done)
+
+	return nil
+}
+
+// Get returns a session by UUID
+func (sm *Manager) Get(ctx context.Context, uuid string) (Caller, error) {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	go func() {
+		select {
+		case <-ctx.Done():
+			sm.updateCondition.Broadcast()
+		}
+	}()
+
+	var c *client
+
+	sm.mu.Lock()
+	for {
+		select {
+		case <-ctx.Done():
+			sm.mu.Unlock()
+			return nil, errors.Wrapf(ctx.Err(), "no active session for %s", uuid)
+		default:
+		}
+		var ok bool
+		c, ok = sm.sessions[uuid]
+		if !ok || c.closed() {
+			sm.updateCondition.Wait()
+			continue
+		}
+		sm.mu.Unlock()
+		break
+	}
+
+	return c, nil
+}
+
+func (c *client) Context() context.Context {
+	return c.context()
+}
+
+func (c *client) Name() string {
+	return c.name
+}
+
+func (c *client) SharedKey() string {
+	return c.sharedKey
+}
+
+func (c *client) Supports(url string) bool {
+	_, ok := c.supported[strings.ToLower(url)]
+	return ok
+}
+func (c *client) Conn() *grpc.ClientConn {
+	return c.cc
+}

client/session/session.go

@@ -0,0 +1,117 @@
+package session
+
+import (
+	"net"
+
+	"github.com/docker/docker/pkg/stringid"
+	"github.com/pkg/errors"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/health"
+	"google.golang.org/grpc/health/grpc_health_v1"
+)
+
+const (
+	headerSessionUUID      = "X-Docker-Expose-Session-Uuid"
+	headerSessionName      = "X-Docker-Expose-Session-Name"
+	headerSessionSharedKey = "X-Docker-Expose-Session-Sharedkey"
+	headerSessionMethod    = "X-Docker-Expose-Session-Grpc-Method"
+)
+
+// Dialer returns a connection that can be used by the session
+type Dialer func(ctx context.Context, proto string, meta map[string][]string) (net.Conn, error)
+
+// Attachable defines a feature that can be expsed on a session
+type Attachable interface {
+	Register(*grpc.Server)
+}
+
+// Session is a long running connection between client and a daemon
+type Session struct {
+	uuid       string
+	name       string
+	sharedKey  string
+	ctx        context.Context
+	cancelCtx  func()
+	done       chan struct{}
+	grpcServer *grpc.Server
+}
+
+// NewSession returns a new long running session
+func NewSession(name, sharedKey string) (*Session, error) {
+	uuid := stringid.GenerateRandomID()
+	s := &Session{
+		uuid:       uuid,
+		name:       name,
+		sharedKey:  sharedKey,
+		grpcServer: grpc.NewServer(),
+	}
+
+	grpc_health_v1.RegisterHealthServer(s.grpcServer, health.NewServer())
+
+	return s, nil
+}
+
+// Allow enable a given service to be reachable through the grpc session
+func (s *Session) Allow(a Attachable) {
+	a.Register(s.grpcServer)
+}
+
+// UUID returns unique identifier for the session
+func (s *Session) UUID() string {
+	return s.uuid
+}
+
+// Run activates the session
+func (s *Session) Run(ctx context.Context, dialer Dialer) error {
+	ctx, cancel := context.WithCancel(ctx)
+	s.cancelCtx = cancel
+	s.done = make(chan struct{})
+
+	defer cancel()
+	defer close(s.done)
+
+	meta := make(map[string][]string)
+	meta[headerSessionUUID] = []string{s.uuid}
+	meta[headerSessionName] = []string{s.name}
+	meta[headerSessionSharedKey] = []string{s.sharedKey}
+
+	for name, svc := range s.grpcServer.GetServiceInfo() {
+		for _, method := range svc.Methods {
+			meta[headerSessionMethod] = append(meta[headerSessionMethod], MethodURL(name, method.Name))
+		}
+	}
+	conn, err := dialer(ctx, "h2c", meta)
+	if err != nil {
+		return errors.Wrap(err, "failed to dial gRPC")
+	}
+	serve(ctx, s.grpcServer, conn)
+	return nil
+}
+
+// Close closes the session
+func (s *Session) Close() error {
+	if s.cancelCtx != nil && s.done != nil {
+		s.cancelCtx()
+		<-s.done
+	}
+	return nil
+}
+
+func (s *Session) context() context.Context {
+	return s.ctx
+}
+
+func (s *Session) closed() bool {
+	select {
+	case <-s.context().Done():
+		return true
+	default:
+		return false
+	}
+}
+
+// MethodURL returns a gRPC method URL for service and method name
+func MethodURL(s, m string) string {
+	return "/" + s + "/" + m
+}

cmd/dockerd/daemon.go

@@ -23,10 +23,12 @@ import (
 	"github.com/docker/docker/api/server/router/image"
 	"github.com/docker/docker/api/server/router/network"
 	pluginrouter "github.com/docker/docker/api/server/router/plugin"
+	sessionrouter "github.com/docker/docker/api/server/router/session"
 	swarmrouter "github.com/docker/docker/api/server/router/swarm"
 	systemrouter "github.com/docker/docker/api/server/router/system"
 	"github.com/docker/docker/api/server/router/volume"
 	"github.com/docker/docker/cli/debug"
+	"github.com/docker/docker/client/session"
 	"github.com/docker/docker/daemon"
 	"github.com/docker/docker/daemon/cluster"
 	"github.com/docker/docker/daemon/config"
@@ -46,6 +48,7 @@ import (
 	"github.com/docker/docker/runconfig"
 	"github.com/docker/go-connections/tlsconfig"
 	swarmapi "github.com/docker/swarmkit/api"
+	"github.com/pkg/errors"
 	"github.com/spf13/pflag"
 )
 
@@ -215,6 +218,11 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 		logrus.Warnln("LCOW support is enabled - this feature is incomplete")
 	}
 
+	sm, err := session.NewManager()
+	if err != nil {
+		return errors.Wrap(err, "failed to create sessionmanager")
+	}
+
 	d, err := daemon.NewDaemon(cli.Config, registryService, containerdRemote, pluginStore)
 	if err != nil {
 		return fmt.Errorf("Error starting daemon: %v", err)
@@ -260,6 +268,11 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 		logrus.Fatalf("Error starting cluster component: %v", err)
 	}
 
+	bb, err := buildbackend.NewBackend(d, d, sm, d.IDMappings())
+	if err != nil {
+		return errors.Wrap(err, "failed to create buildmanager")
+	}
+
 	// Restart all autostart containers which has a swarm endpoint
 	// and is not yet running now that we have successfully
 	// initialized the cluster.
@@ -269,7 +282,7 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 
 	cli.d = d
 
-	initRouter(api, d, c)
+	initRouter(api, d, c, sm, bb)
 
 	// process cluster change notifications
 	watchCtx, cancel := context.WithCancel(context.Background())
@@ -442,7 +455,7 @@ func loadDaemonCliConfig(opts *daemonOptions) (*config.Config, error) {
 	return conf, nil
 }
 
-func initRouter(s *apiserver.Server, d *daemon.Daemon, c *cluster.Cluster) {
+func initRouter(s *apiserver.Server, d *daemon.Daemon, c *cluster.Cluster, sm *session.Manager, bb *buildbackend.Backend) {
 	decoder := runconfig.ContainerDecoder{}
 
 	routers := []router.Router{
@@ -452,7 +465,8 @@ func initRouter(s *apiserver.Server, d *daemon.Daemon, c *cluster.Cluster) {
 		image.NewRouter(d, decoder),
 		systemrouter.NewRouter(d, c),
 		volume.NewRouter(d),
-		build.NewRouter(buildbackend.NewBackend(d, d, d.IDMappings()), d),
+		build.NewRouter(bb, d),
+		sessionrouter.NewRouter(sm),
 		swarmrouter.NewRouter(c),
 		pluginrouter.NewRouter(d.PluginManager()),
 		distributionrouter.NewRouter(d),

integration-cli/docker_api_session_test.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/docker/docker/integration-cli/checker"
+	"github.com/docker/docker/integration-cli/request"
+	"github.com/docker/docker/pkg/testutil"
+	"github.com/go-check/check"
+)
+
+func (s *DockerSuite) TestSessionCreate(c *check.C) {
+	testRequires(c, ExperimentalDaemon)
+
+	res, body, err := request.Post("/session", func(r *http.Request) error {
+		r.Header.Set("X-Docker-Expose-Session-Uuid", "testsessioncreate") // so we don't block default name if something else is using it
+		r.Header.Set("Upgrade", "h2c")
+		return nil
+	})
+	c.Assert(err, checker.IsNil)
+	c.Assert(res.StatusCode, checker.Equals, http.StatusSwitchingProtocols)
+	c.Assert(res.Header.Get("Upgrade"), checker.Equals, "h2c")
+	c.Assert(body.Close(), checker.IsNil)
+}
+
+func (s *DockerSuite) TestSessionCreateWithBadUpgrade(c *check.C) {
+	testRequires(c, ExperimentalDaemon)
+
+	res, body, err := request.Post("/session")
+	c.Assert(err, checker.IsNil)
+	c.Assert(res.StatusCode, checker.Equals, http.StatusBadRequest)
+	buf, err := testutil.ReadBody(body)
+	c.Assert(err, checker.IsNil)
+
+	out := string(buf)
+	c.Assert(out, checker.Contains, "no upgrade")
+
+	res, body, err = request.Post("/session", func(r *http.Request) error {
+		r.Header.Set("Upgrade", "foo")
+		return nil
+	})
+	c.Assert(err, checker.IsNil)
+	c.Assert(res.StatusCode, checker.Equals, http.StatusBadRequest)
+	buf, err = testutil.ReadBody(body)
+	c.Assert(err, checker.IsNil)
+
+	out = string(buf)
+	c.Assert(out, checker.Contains, "not supported")
+}

vendor/google.golang.org/grpc/health/health.go

@@ -0,0 +1,52 @@
+// Package health provides some utility functions to health-check a server. The implementation
+// is based on protobuf. Users need to write their own implementations if other IDLs are used.
+package health
+
+import (
+	"sync"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+)
+
+// Server implements `service Health`.
+type Server struct {
+	mu sync.Mutex
+	// statusMap stores the serving status of the services this Server monitors.
+	statusMap map[string]healthpb.HealthCheckResponse_ServingStatus
+}
+
+// NewServer returns a new Server.
+func NewServer() *Server {
+	return &Server{
+		statusMap: make(map[string]healthpb.HealthCheckResponse_ServingStatus),
+	}
+}
+
+// Check implements `service Health`.
+func (s *Server) Check(ctx context.Context, in *healthpb.HealthCheckRequest) (*healthpb.HealthCheckResponse, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if in.Service == "" {
+		// check the server overall health status.
+		return &healthpb.HealthCheckResponse{
+			Status: healthpb.HealthCheckResponse_SERVING,
+		}, nil
+	}
+	if status, ok := s.statusMap[in.Service]; ok {
+		return &healthpb.HealthCheckResponse{
+			Status: status,
+		}, nil
+	}
+	return nil, grpc.Errorf(codes.NotFound, "unknown service")
+}
+
+// SetServingStatus is called when need to reset the serving status of a service
+// or insert a new service entry into the statusMap.
+func (s *Server) SetServingStatus(service string, status healthpb.HealthCheckResponse_ServingStatus) {
+	s.mu.Lock()
+	s.statusMap[service] = status
+	s.mu.Unlock()
+}