Implement activation service

Signed-off-by: Daniel Weiße <dw@edgeless.systems>

activation/server/server.go

@@ -0,0 +1,128 @@
+package server
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"net"
+	"time"
+
+	proto "github.com/edgelesssys/constellation/activation/activationproto"
+	"github.com/edgelesssys/constellation/internal/constants"
+	"github.com/edgelesssys/constellation/internal/file"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/status"
+	"k8s.io/klog/v2"
+
+	kubeadmv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
+)
+
+// Server implements the core logic of Constellation's node activation service.
+type Server struct {
+	file            file.Handler
+	joinTokenGetter joinTokenGetter
+	dataKeyGetter   dataKeyGetter
+	proto.UnimplementedAPIServer
+}
+
+// New initializes a new Server.
+func New(fileHandler file.Handler, joinTokenGetter joinTokenGetter, dataKeyGetter dataKeyGetter) *Server {
+	return &Server{
+		file:            fileHandler,
+		joinTokenGetter: joinTokenGetter,
+		dataKeyGetter:   dataKeyGetter,
+	}
+}
+
+// Run starts the gRPC server on the given port, using the provided tlsConfig.
+func (s *Server) Run(tlsConfig *tls.Config, port string) error {
+	grpcServer := grpc.NewServer(
+		grpc.Creds(credentials.NewTLS(tlsConfig)),
+		grpc.UnaryInterceptor(logGRPC),
+	)
+
+	proto.RegisterAPIServer(grpcServer, s)
+
+	lis, err := net.Listen("tcp", net.JoinHostPort("", port))
+	if err != nil {
+		return fmt.Errorf("failed to listen: %s", err)
+	}
+	klog.V(2).Infof("starting activation service on %s", lis.Addr().String())
+	return grpcServer.Serve(lis)
+}
+
+// ActivateNode handles activation requests of Constellation worker nodes.
+// A worker node will receive:
+// - stateful disk encryption key.
+// - Kubernetes join token.
+// - cluster and owner ID to taint the node as initialized.
+func (s *Server) ActivateNode(ctx context.Context, req *proto.ActivateNodeRequest) (*proto.ActivateNodeResponse, error) {
+	klog.V(4).Infof("ActivateNode: loading IDs")
+	var id id
+	if err := s.file.ReadJSON(constants.ActivationIDFilename, &id); err != nil {
+		klog.Errorf("unable to load IDs: %s", err)
+		return nil, status.Errorf(codes.Internal, "unable to load IDs: %s", err)
+	}
+
+	klog.V(4).Infof("ActivateNode: requesting disk encryption key")
+	stateDiskKey, err := s.dataKeyGetter.GetDataKey(ctx, req.DiskUuid, constants.StateDiskKeyLength)
+	if err != nil {
+		klog.Errorf("unable to get key for stateful disk: %s", err)
+		return nil, status.Errorf(codes.Internal, "unable to get key for stateful disk: %s", err)
+	}
+
+	klog.V(4).Infof("ActivateNode: creating Kubernetes join token")
+	kubeArgs, err := s.joinTokenGetter.GetJoinToken(constants.KubernetesJoinTokenTTL)
+	if err != nil {
+		klog.Errorf("unable to generate Kubernetes join arguments: %s", err)
+		return nil, status.Errorf(codes.Internal, "unable to generate Kubernetes join arguments: %s", err)
+	}
+
+	klog.V(4).Info("ActivateNode successful")
+
+	return &proto.ActivateNodeResponse{
+		StateDiskKey:             stateDiskKey,
+		ClusterId:                id.Cluster,
+		OwnerId:                  id.Owner,
+		ApiServerEndpoint:        kubeArgs.APIServerEndpoint,
+		Token:                    kubeArgs.Token,
+		DiscoveryTokenCaCertHash: kubeArgs.CACertHashes[0],
+	}, nil
+}
+
+// ActivateCoordinator handles activation requests of Constellation control-plane nodes.
+func (s *Server) ActivateCoordinator(ctx context.Context, req *proto.ActivateCoordinatorRequest) (*proto.ActivateCoordinatorResponse, error) {
+	panic("not implemented")
+}
+
+// joinTokenGetter returns Kubernetes bootstrap (join) tokens.
+type joinTokenGetter interface {
+	// GetJoinToken returns a bootstrap (join) token.
+	GetJoinToken(ttl time.Duration) (*kubeadmv1.BootstrapTokenDiscovery, error)
+}
+
+// dataKeyGetter interacts with Constellation's key management system to retrieve keys.
+type dataKeyGetter interface {
+	// GetDataKey returns a key derived from Constellation's KMS.
+	GetDataKey(ctx context.Context, uuid string, length int) ([]byte, error)
+}
+
+type id struct {
+	Cluster []byte `json:"cluster"`
+	Owner   []byte `json:"owner"`
+}
+
+// logGRPC writes a log with the name of every gRPC call or error it receives.
+func logGRPC(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
+	// log the requests method name
+	klog.V(2).Infof("GRPC call: %s", info.FullMethod)
+
+	// log errors, if any
+	resp, err := handler(ctx, req)
+	if err != nil {
+		klog.Errorf("GRPC error: %v", err)
+	}
+	return resp, err
+}