containerd-shim-kata-v2: add the service Pause support

Add the Pause api support to pause a container running
in the pod.

Signed-off-by: ZeroMagic <anthonyliu@zju.edu.cn>

containerd-shim-v2/service.go

@@ -497,7 +497,28 @@ func (s *service) State(ctx context.Context, r *taskAPI.StateRequest) (*taskAPI.
 
 // Pause the container
 func (s *service) Pause(ctx context.Context, r *taskAPI.PauseRequest) (*ptypes.Empty, error) {
-	return nil, errdefs.ErrNotImplemented
+	s.Lock()
+	defer s.Unlock()
+
+	c, err := s.getContainer(r.ID)
+	if err != nil {
+		return nil, err
+	}
+
+	c.status = task.StatusPausing
+
+	err = s.sandbox.PauseContainer(r.ID)
+	if err == nil {
+		c.status = task.StatusPaused
+		return empty, nil
+	}
+
+	c.status, err = s.getContainerStatus(c.id)
+	if err != nil {
+		c.status = task.StatusUnknown
+	}
+
+	return empty, err
 }
 
 // Resume the container
@@ -678,3 +699,24 @@ func (s *service) getContainer(id string) (*container, error) {
 
 	return c, nil
 }
+
+func (s *service) getContainerStatus(containerID string) (task.Status, error) {
+	cStatus, err := s.sandbox.StatusContainer(containerID)
+	if err != nil {
+		return task.StatusUnknown, err
+	}
+
+	var status task.Status
+	switch cStatus.State.State {
+	case vc.StateReady:
+		status = task.StatusCreated
+	case vc.StateRunning:
+		status = task.StatusRunning
+	case vc.StatePaused:
+		status = task.StatusPaused
+	case vc.StateStopped:
+		status = task.StatusStopped
+	}
+
+	return status, nil
+}