Refactor: move cache calls into separate functions

Need to split out the caching functions, from the loading/copying.

Also need to make the lists accessible from outside the functions.

cmd/minikube/cmd/cache.go

@@ -66,20 +66,31 @@ var deleteCacheCmd = &cobra.Command{
 	},
 }
 
-// LoadCachedImagesInConfigFile loads the images currently in the config file (minikube start)
-func LoadCachedImagesInConfigFile() error {
+func imagesInConfigFile() ([]string, error) {
 	configFile, err := config.ReadConfig()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	if values, ok := configFile[constants.Cache]; ok {
 		var images []string
 		for key := range values.(map[string]interface{}) {
 			images = append(images, key)
 		}
-		return machine.CacheAndLoadImages(images)
+		return images, nil
 	}
-	return nil
+	return []string{}, nil
+}
+
+// LoadCachedImagesInConfigFile loads the images currently in the config file (minikube start)
+func LoadCachedImagesInConfigFile() error {
+	images, err := imagesInConfigFile()
+	if err != nil {
+		return err
+	}
+	if len(images) == 0 {
+		return nil
+	}
+	return machine.CacheAndLoadImages(images)
 }
 
 func init() {

pkg/minikube/bootstrapper/kubeadm/kubeadm.go

@@ -466,19 +466,16 @@ func (k *Bootstrapper) UpdateCluster(cfg config.KubernetesConfig) error {
 	}
 
 	var g errgroup.Group
-	for _, bin := range []string{"kubelet", "kubeadm"} {
+	for _, bin := range constants.GetKubeadmCachedBinaries() {
 		bin := bin
 		g.Go(func() error {
-			path, err := maybeDownloadAndCache(bin, cfg.KubernetesVersion)
+			path, err := CacheBinary(bin, cfg.KubernetesVersion)
 			if err != nil {
 				return errors.Wrapf(err, "downloading %s", bin)
 			}
-			f, err := assets.NewFileAsset(path, "/usr/bin", bin, "0641")
+			err = CopyBinary(k.c, bin, path)
 			if err != nil {
-				return errors.Wrap(err, "new file asset")
-			}
-			if err := k.c.Copy(f); err != nil {
-				return errors.Wrapf(err, "copy")
+				return errors.Wrapf(err, "copying %s", bin)
 			}
 			return nil
 		})
@@ -584,13 +581,17 @@ func generateConfig(k8s config.KubernetesConfig, r cruntime.Manager) (string, er
 	return b.String(), nil
 }
 
-func maybeDownloadAndCache(binary, version string) (string, error) {
+// CacheBinary will cache a binary on the host
+func CacheBinary(binary, version string) (string, error) {
 	targetDir := constants.MakeMiniPath("cache", version)
 	targetFilepath := path.Join(targetDir, binary)
 
+	url := constants.GetKubernetesReleaseURL(binary, version)
+
 	_, err := os.Stat(targetFilepath)
 	// If it exists, do no verification and continue
 	if err == nil {
+		glog.Infof("Not caching binary, using %s", url)
 		return targetFilepath, nil
 	}
 	if !os.IsNotExist(err) {
@@ -601,7 +602,6 @@ func maybeDownloadAndCache(binary, version string) (string, error) {
 		return "", errors.Wrapf(err, "mkdir %s", targetDir)
 	}
 
-	url := constants.GetKubernetesReleaseURL(binary, version)
 	options := download.FileOptions{
 		Mkdirs: download.MkdirAll,
 	}
@@ -615,3 +615,15 @@ func maybeDownloadAndCache(binary, version string) (string, error) {
 	}
 	return targetFilepath, nil
 }
+
+// CopyBinary copies previously cached binaries into the path
+func CopyBinary(cr bootstrapper.CommandRunner, binary, path string) error {
+	f, err := assets.NewFileAsset(path, "/usr/bin", binary, "0641")
+	if err != nil {
+		return errors.Wrap(err, "new file asset")
+	}
+	if err := cr.Copy(f); err != nil {
+		return errors.Wrapf(err, "copy")
+	}
+	return nil
+}

pkg/minikube/cluster/cluster.go

@@ -58,6 +58,16 @@ func init() {
 	ssh.SetDefaultClient(ssh.Native)
 }
 
+// CacheISO downloads and caches ISO.
+func CacheISO(config cfg.MachineConfig) error {
+	if config.VMDriver != "none" {
+		if err := config.Downloader.CacheMinikubeISOFromURL(config.MinikubeISO); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // StartHost starts a host VM.
 func StartHost(api libmachine.API, config cfg.MachineConfig) (*host.Host, error) {
 	exists, err := api.Exists(cfg.GetMachineName())
@@ -280,10 +290,9 @@ func createHost(api libmachine.API, config cfg.MachineConfig) (*host.Host, error
 		exit.WithError("error getting driver", err)
 	}
 
-	if config.VMDriver != "none" {
-		if err := config.Downloader.CacheMinikubeISOFromURL(config.MinikubeISO); err != nil {
-			return nil, errors.Wrap(err, "unable to cache ISO")
-		}
+	err = CacheISO(config)
+	if err != nil {
+		return nil, errors.Wrap(err, "unable to cache ISO")
 	}
 
 	driver := def.ConfigCreator(config)

pkg/minikube/constants/constants.go

@@ -224,6 +224,11 @@ const DriverNone = "none"
 // FileScheme is the file scheme
 const FileScheme = "file"
 
+// GetKubeadmCachedBinaries gets the binaries to cache for kubeadm
+func GetKubeadmCachedBinaries() []string {
+	return []string{"kubelet", "kubeadm"}
+}
+
 // GetKubeadmCachedImages gets the images to cache for kubeadm for a version
 func GetKubeadmCachedImages(imageRepository string, kubernetesVersionStr string) (string, []string) {
 	minikubeRepository := imageRepository