vendor: add buildkit

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

vendor/github.com/moby/buildkit/session/manager.go

@@ -0,0 +1,218 @@
+package session
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/pkg/errors"
+	"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")
+	}
+
+	id := r.Header.Get(headerSessionID)
+
+	proto := r.Header.Get("Upgrade")
+
+	sm.mu.Lock()
+	if _, ok := sm.sessions[id]; ok {
+		sm.mu.Unlock()
+		return errors.Errorf("session %s already exists", id)
+	}
+
+	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)
+
+	return sm.handleConn(ctx, conn, r.Header)
+}
+
+// HandleConn handles an incoming raw connection
+func (sm *Manager) HandleConn(ctx context.Context, conn net.Conn, opts map[string][]string) error {
+	sm.mu.Lock()
+	return sm.handleConn(ctx, conn, opts)
+}
+
+// caller needs to take lock, this function will release it
+func (sm *Manager) handleConn(ctx context.Context, conn net.Conn, opts map[string][]string) error {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	opts = canonicalHeaders(opts)
+
+	h := http.Header(opts)
+	id := h.Get(headerSessionID)
+	name := h.Get(headerSessionName)
+	sharedKey := h.Get(headerSessionSharedKey)
+
+	ctx, cc, err := grpcClientConn(ctx, conn)
+	if err != nil {
+		sm.mu.Unlock()
+		return err
+	}
+
+	c := &client{
+		Session: Session{
+			id:        id,
+			name:      name,
+			sharedKey: sharedKey,
+			ctx:       ctx,
+			cancelCtx: cancel,
+			done:      make(chan struct{}),
+		},
+		cc:        cc,
+		supported: make(map[string]struct{}),
+	}
+
+	for _, m := range opts[headerSessionMethod] {
+		c.supported[strings.ToLower(m)] = struct{}{}
+	}
+	sm.sessions[id] = c
+	sm.updateCondition.Broadcast()
+	sm.mu.Unlock()
+
+	defer func() {
+		sm.mu.Lock()
+		delete(sm.sessions, id)
+		sm.mu.Unlock()
+	}()
+
+	<-c.ctx.Done()
+	conn.Close()
+	close(c.done)
+
+	return nil
+}
+
+// Get returns a session by ID
+func (sm *Manager) Get(ctx context.Context, id string) (Caller, error) {
+	// session prefix is used to identify vertexes with different contexts so
+	// they would not collide, but for lookup we don't need the prefix
+	if p := strings.SplitN(id, ":", 2); len(p) == 2 && len(p[1]) > 0 {
+		id = p[1]
+	}
+
+	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", id)
+		default:
+		}
+		var ok bool
+		c, ok = sm.sessions[id]
+		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
+}
+
+func canonicalHeaders(in map[string][]string) map[string][]string {
+	out := map[string][]string{}
+	for k := range in {
+		out[http.CanonicalHeaderKey(k)] = in[k]
+	}
+	return out
+}