add label flags to ctr import, add integration tests

Signed-off-by: roman-kiselenko <roman.kiselenko.dev@gmail.com>

client/import.go

@@ -38,6 +38,7 @@ type importOpts struct {
 	compress        bool
 	discardLayers   bool
 	skipMissing     bool
+	imageLabels     map[string]string
 }
 
 // ImportOpt allows the caller to specify import specific options
@@ -52,6 +53,14 @@ func WithImageRefTranslator(f func(string) string) ImportOpt {
 	}
 }
 
+// WithImageLabels are the image labels to apply to a new image
+func WithImageLabels(labels map[string]string) ImportOpt {
+	return func(c *importOpts) error {
+		c.imageLabels = labels
+		return nil
+	}
+}
+
 // WithDigestRef is used to create digest images for each
 // manifest in the index.
 func WithDigestRef(f func(digest.Digest) string) ImportOpt {
@@ -223,7 +232,12 @@ func (c *Client) Import(ctx context.Context, reader io.Reader, opts ...ImportOpt
 	}
 
 	for i := range imgs {
-		img, err := is.Update(ctx, imgs[i], "target")
+		fieldsPath := []string{"target"}
+		if iopts.imageLabels != nil {
+			fieldsPath = append(fieldsPath, "labels")
+			imgs[i].Labels = iopts.imageLabels
+		}
+		img, err := is.Update(ctx, imgs[i], fieldsPath...)
 		if err != nil {
 			if !errdefs.IsNotFound(err) {
 				return nil, err