fix: fix empty tarball when generating image save

Author: ComradeProgrammer

pkg/minikube/cruntime/containerd.go

@@ -265,7 +265,7 @@ func (r *Containerd) Disable() error {
 // ImageExists checks if image exists based on image name and optionally image sha
 func (r *Containerd) ImageExists(name string, sha string) bool {
 	klog.Infof("Checking existence of image with name %q and sha %q", name, sha)
-	c := exec.Command("sudo", "ctr", "-n=k8s.io", "images", "check")
+	c := exec.Command("sudo", "ctr", "-n=k8s.io", "images", "ls", fmt.Sprintf("name==%s", name))
 	// note: image name and image id's sha can be on different lines in ctr output
 	if rr, err := r.Runner.RunCmd(c); err != nil ||
 		!strings.Contains(rr.Output(), name) ||

pkg/minikube/cruntime/docker.go

@@ -292,7 +292,7 @@ func (r *Docker) ListImages(ListImagesOptions) ([]ListImage, error) {
 		result = append(result, ListImage{
 			ID:          strings.TrimPrefix(jsonImage.ID, "sha256:"),
 			RepoDigests: []string{},
-			RepoTags:    []string{addDockerIO(repoTag)},
+			RepoTags:    []string{AddDockerIO(repoTag)},
 			Size:        fmt.Sprintf("%d", size),
 		})
 	}
@@ -696,10 +696,13 @@ func dockerImagesPreloaded(runner command.Runner, images []string) bool {
 }
 
 // Add docker.io prefix
-func addDockerIO(name string) string {
+func AddDockerIO(name string) string {
 	var reg, usr, img string
 	p := strings.SplitN(name, "/", 2)
-	if len(p) > 1 && strings.Contains(p[0], ".") {
+	// containing . means that it is a valid url for registry(e.g. xxx.io)
+	// containing : means it contains some port number (e.g. xxx:5432)
+	// it may also start with localhost, which is also regarded as a valid registry
+	if len(p) > 1 && (strings.Contains(p[0], ".") || strings.Contains(p[0], ":") || strings.Contains(p[0], "localhost")) {
 		reg = p[0]
 		img = p[1]
 	} else {

pkg/minikube/machine/cache_images.go

@@ -474,7 +474,11 @@ func transferAndSaveImage(cr command.Runner, k8s config.KubernetesConfig, dst st
 	}
 
 	if !r.ImageExists(imgName, "") {
-		return errors.Errorf("image %s not found", imgName)
+		imgName = cruntime.AddDockerIO(imgName)
+		// we add the image name with default prefix docker.io if it doesn't specify a registry
+		if !r.ImageExists(imgName, "") {
+			return errors.Errorf("image %s not found", imgName)
+		}
 	}
 
 	klog.Infof("Saving image to: %s", dst)

test/integration/functional_test.go

@@ -57,7 +57,7 @@ import (
 	"golang.org/x/build/kubernetes/api"
 )
 
-const echoServerImg = "docker.io/kicbase/echo-server"
+const echoServerImg = "kicbase/echo-server"
 
 // validateFunc are for subtests that share a single setup
 type validateFunc func(context.Context, *testing.T, string)