Do not cache image handler.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/helpers.go

@@ -25,6 +25,7 @@ import (
 	"strings"
 
 	"github.com/BurntSushi/toml"
+	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/containers"
 	"github.com/containerd/containerd/runtime/linux/runctypes"
 	runcoptions "github.com/containerd/containerd/runtime/v2/runc/options"
@@ -254,6 +255,15 @@ func (c *criService) localResolve(refOrID string) (imagestore.Image, error) {
 	return c.imageStore.Get(imageID)
 }
 
+// toContainerdImage converts an image object in image store to containerd image handler.
+func (c *criService) toContainerdImage(ctx context.Context, image imagestore.Image) (containerd.Image, error) {
+	// image should always have at least one reference.
+	if len(image.References) == 0 {
+		return nil, errors.Errorf("invalid image with no reference %q", image.ID)
+	}
+	return c.client.GetImage(ctx, image.References[0])
+}
+
 // getUserFromImage gets uid or user name of the image user.
 // If user is numeric, it will be treated as uid; or else, it is treated as user name.
 func getUserFromImage(user string) (*int64, string) {