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 ( headerSessionID = "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 { id 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) { id := stringid.GenerateRandomID() s := &Session{ id: id, 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) } // ID returns unique identifier for the session func (s *Session) ID() string { return s.id } // 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[headerSessionID] = []string{s.id} 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.grpcServer.Stop() 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 }