Extend sealer save to support multi-image-archive and tmp-dir

feature: Extend the save flag option and function

Signed-off-by: Xinwei Xiong(cubxxw) <[email protected]>

Author: cubxxw

cmd/sealer/cmd/image/load.go

@@ -24,13 +24,17 @@ import (
 	"github.com/sealerio/sealer/pkg/imageengine"
 )
 
-var loadOpts *options.LoadOptions
+var (
+	loadOpts *options.LoadOptions
 
-var longNewLoadCmdDescription = `Load a sealer image from a tar archive`
+	longNewLoadCmdDescription = `
+  Load a sealer image from a tar archive
+  Save an image to docker-archive or oci-archive on the local machine. Default is docker-archive.`
 
-var exampleForLoadCmd = `
+	exampleForLoadCmd = `
   sealer load -i kubernetes.tar
-`
+  sealer save abc:v1 -o my.tar --tmp-dir /root/my-tmp`
+)
 
 // NewLoadCmd loadCmd represents the load command
 func NewLoadCmd() *cobra.Command {
@@ -58,7 +62,7 @@ func NewLoadCmd() *cobra.Command {
 	flags := loadCmd.Flags()
 	flags.StringVarP(&loadOpts.Input, "input", "i", "", "Load image from file")
 	flags.BoolVarP(&loadOpts.Quiet, "quiet", "q", false, "Suppress the output")
-	flags.StringVar(&loadOpts.TmpDir, "tmp-dir", "", "set temporary directory when load image. if not set, use system`s temporary directory")
+	flags.StringVar(&loadOpts.TmpDir, "tmp-dir", "", "Set temporary directory when load image. if not set, use system temporary directory(`/var/tmp/`)")
 	if err := loadCmd.MarkFlagRequired("input"); err != nil {
 		logrus.Errorf("failed to init flag: %v", err)
 		os.Exit(1)

cmd/sealer/cmd/image/save.go

@@ -15,8 +15,6 @@
 package image
 
 import (
-	"os"
-
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 
@@ -25,14 +23,24 @@ import (
 	"github.com/sealerio/sealer/pkg/imageengine/buildah"
 )
 
-var saveOpts *options.SaveOptions
+var (
+	saveOpts *options.SaveOptions
+
+	longNewSaveCmdDescription = `
+  sealer save -o [output file name] [image name]
+  Save an image to docker-archive or oci-archive on the local machine. Default is docker-archive.`
+
+	exampleForSaveCmd = `
+  sealer save docker.io/sealerio/kubernetes:v1-22-15-sealerio-2 
 
-var longNewSaveCmdDescription = `sealer save -o [output file name] [image name]`
+Image to kubernetes.tar file, and specify the temporary load directory:
 
-var exampleForSaveCmd = `
-save docker.io/sealerio/kubernetes:v1-22-15-sealerio-2 image to kubernetes.tar file:
+  sealer save docker.io/sealerio/kubernetes:v1.22.15  -o kubernetes.tar --tmp-dir /root/tmp`
+)
 
-  sealer save -o kubernetes.tar docker.io/sealerio/kubernetes:v1-22-15-sealerio-2`
+var (
+	containerConfig = buildah.NewPodmanConfig()
+)
 
 // NewSaveCmd saveCmd represents the save command
 func NewSaveCmd() *cobra.Command {
@@ -59,14 +67,26 @@ func NewSaveCmd() *cobra.Command {
 	}
 	saveOpts = &options.SaveOptions{}
 	flags := saveCmd.Flags()
-	flags.StringVar(&saveOpts.Format, "format", buildah.OCIArchive, "Save image to oci-archive, oci-dir (directory with oci manifest type), docker-archive, docker-dir (directory with v2s2 manifest type)")
-	flags.StringVarP(&saveOpts.Output, "output", "o", "", "Write image to a specified file")
+
+	formatFlagName := "format"
+	flags.StringVar(&saveOpts.Format, formatFlagName, buildah.OCIArchive, "Save image to oci-archive, oci-dir (directory with oci manifest type), docker-archive, docker-dir (directory with v2s2 manifest type)")
+
+	outputFlagName := "output"
+	flags.StringVarP(&saveOpts.Output, outputFlagName, "o", "", "Write to a specified file (default: stdout, which must be redirected)")
+
+	// TODO: Waiting for implementation, not yet supported
+	flags.StringVar(&loadOpts.TmpDir, "tmp-dir", "", "Set temporary directory when load image. use system temporary directory(/var/tmp/) if not present.")
+
 	flags.BoolVarP(&saveOpts.Quiet, "quiet", "q", false, "Suppress the output")
-	flags.StringVar(&saveOpts.TmpDir, "tmp-dir", "", "set temporary directory when save image. if not set, use system`s temporary directory")
-	flags.BoolVar(&saveOpts.Compress, "compress", false, "Compress tarball image layers when saving to a directory using the 'dir' transport. (default is same compression type as source)")
+
+	compressFlagName := "compress"
+	flags.BoolVar(&saveOpts.Compress, compressFlagName, false, "Compress tarball image layers when saving to a directory using the 'dir' transport. (default is same compression type as source)")
+
+	MultiImageArchiveFlagName := "multi-image-archive"
+	flags.BoolVarP(&saveOpts.MultiImageArchive, MultiImageArchiveFlagName, "m", containerConfig.ContainersConfDefaultsRO.Engine.MultiImageArchive, "Interpret additional arguments as images not tags and create a multi-image-archive (only for docker-archive)")
+
 	if err := saveCmd.MarkFlagRequired("output"); err != nil {
-		logrus.Errorf("failed to init flag: %v", err)
-		os.Exit(1)
+		logrus.WithError(err).Fatal("failed to mark flag as required")
 	}
 
 	return saveCmd

pkg/define/options/options.go

@@ -120,15 +120,16 @@ type ImagesOptions struct {
 	JSON      bool
 }
 
+// SaveOptions provide options for saving images.
 type SaveOptions struct {
-	Compress bool
-	Format   string
-	// don't support currently
-	MultiImageArchive bool
-	Output            string
-	Quiet             bool
-	ImageNameOrID     string
-	TmpDir            string
+	Compress          bool   // Whether or not to compress the image layers when saving to a directory. Default is false.
+	Format            string // The format to save the image in. Possible values are oci-archive, oci-dir, docker-archive, and docker-dir. Default is oci-archive.
+	MultiImageArchive bool   // Whether or not to save multiple images into a single archive file. Default is false.
+	Output            string // The file or directory to save the image to. If not set, output will go to stdout.
+	Quiet             bool   // Whether or not to suppress output when saving the image. Default is false.
+	ImageNameOrID     string // The name or ID of the image to save.
+	// // TODO: unrealized, Set temporary directory when save image. if not set, use system temporary directory(`/var/tmp/`)
+	TmpDir string
 }
 
 type LoadOptions struct {

pkg/image/save/save.go

@@ -71,22 +71,22 @@ func (is *DefaultImageSaver) SaveImages(images []string, dir string, platform v1
 		}
 	}()
 
-	//handle image name
+	// handle image name
 	for _, image := range images {
 		named, err := ParseNormalizedNamed(image, "")
 		if err != nil {
 			return fmt.Errorf("failed to parse image name:: %v", err)
 		}
 
-		//check if image exist
+		// check if image exist
 		if err := is.isImageExist(named, dir, platform); err == nil {
 			continue
 		}
 		is.domainToImages[named.domain+named.repo] = append(is.domainToImages[named.domain+named.repo], named)
 		progress.Message(is.progressOut, "", fmt.Sprintf("Pulling image: %s", named.FullName()))
 	}
 
-	//perform image save ability
+	// perform image save ability
 	eg, _ := errgroup.WithContext(context.Background())
 	numCh := make(chan struct{}, maxPullGoroutineNum)
 	for _, nameds := range is.domainToImages {

pkg/imageengine/buildah/from.go

@@ -38,6 +38,15 @@ type fromFlagsWrapper struct {
 	*buildahcli.NameSpaceResults
 }
 
+type BuildahConfig struct {
+	ContainersConfDefaultsRO config.Config
+}
+
+func NewPodmanConfig() *BuildahConfig {
+	var buildOptions BuildahConfig
+	return &buildOptions
+}
+
 // createContainerFromImage create a working container. This function is copied from
 // "buildah from". This function takes args([]string{"$image"}), and create a working container
 // based on $image, this will generate an empty dictionary, not a real rootfs. And this container is a fake container.

pkg/imageengine/buildah/load.go

@@ -62,9 +62,8 @@ func (engine *Engine) Load(opts *options.LoadOptions) error {
 	}
 
 	defer func() {
-		err = os.RemoveAll(tempDir)
-		if err != nil {
-			logrus.Errorf("failed to delete %s: %v", tempDir, err)
+		if err = os.RemoveAll(tempDir); err != nil {
+			logrus.Warnf("failed to delete %s: %v", tempDir, err)
 		}
 	}()
 

pkg/imageengine/buildah/save.go

@@ -22,6 +22,7 @@ import (
 	"path/filepath"
 
 	"github.com/containers/common/libimage"
+	"github.com/containers/common/pkg/auth"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 
@@ -34,42 +35,54 @@ import (
 
 // Save image as tar file, if image is multi-arch image, will save all its instances and manifest name as tar file.
 func (engine *Engine) Save(opts *options.SaveOptions) error {
-	imageNameOrID := opts.ImageNameOrID
-	imageTar := opts.Output
+	var (
+		imageNameOrID = opts.ImageNameOrID
+		output        = opts.Output
+		format        = opts.Format
+		tmpDir        = opts.TmpDir
+		compress      = opts.Compress
+	)
+
+	systemCxt := engine.SystemContext()
+	if err := auth.CheckAuthFile(systemCxt.AuthFilePath); err != nil {
+		return err
+	}
+
+	systemCxt.BigFilesTemporaryDir = tmpDir
 
 	if len(imageNameOrID) == 0 {
-		return errors.New("image name or id must be specified")
+		return errors.New("failed to save image, image name or id is empty")
 	}
-	if opts.Compress && (opts.Format != OCIManifestDir && opts.Format != V2s2ManifestDir) {
+
+	if compress && (format != OCIManifestDir && format != V2s2ManifestDir) {
 		return errors.New("--compress can only be set when --format is either 'oci-dir' or 'docker-dir'")
 	}
 
-	img, _, err := engine.ImageRuntime().LookupImage(imageNameOrID, &libimage.LookupImageOptions{
-		ManifestList: true,
-	})
+	img, _, err := engine.ImageRuntime().LookupImage(imageNameOrID,
+		&libimage.LookupImageOptions{
+			ManifestList: true,
+		})
 	if err != nil {
 		return err
 	}
 
-	isManifest, err := img.IsManifestList(getContext())
-	if err != nil {
+	// checks if the image is a manifest list or an image index, and saves the image if it is not
+	if isManifest, err := img.IsManifestList(getContext()); err != nil {
 		return err
-	}
-
-	if !isManifest {
-		return engine.saveOneImage(imageNameOrID, opts.Format, imageTar, opts.Compress)
+	} else if !isManifest {
+		return engine.saveOneImage(imageNameOrID, format, output, compress)
 	}
 
 	// save multi-arch images :including each platform images and manifest.
-	var pathsToCompress []string
+	pathsToCompress := []string{}
 
-	if err := fs.FS.MkdirAll(filepath.Dir(imageTar)); err != nil {
-		return fmt.Errorf("failed to create %s, err: %v", imageTar, err)
+	if err := fs.FS.MkdirAll(filepath.Dir(output)); err != nil {
+		return fmt.Errorf("failed to create %s, err: %v", output, err)
 	}
 
-	file, err := os.Create(filepath.Clean(imageTar))
+	file, err := os.Create(filepath.Clean(output))
 	if err != nil {
-		return fmt.Errorf("failed to create %s, err: %v", imageTar, err)
+		return fmt.Errorf("failed to create %s, err: %v", output, err)
 	}
 
 	defer func() {
@@ -78,14 +91,13 @@ func (engine *Engine) Save(opts *options.SaveOptions) error {
 		}
 	}()
 
-	tempDir, err := os.MkdirTemp(opts.TmpDir, "sealer-save-tmp")
+	tempDir, err := os.MkdirTemp(tmpDir, "sealer-save-tmp")
 	if err != nil {
 		return fmt.Errorf("failed to create %s, err: %v", tempDir, err)
 	}
 
 	defer func() {
-		err = os.RemoveAll(tempDir)
-		if err != nil {
+		if err = os.RemoveAll(tempDir); err != nil {
 			logrus.Warnf("failed to delete %s: %v", tempDir, err)
 		}
 	}()
@@ -110,7 +122,7 @@ func (engine *Engine) Save(opts *options.SaveOptions) error {
 		}
 
 		instanceTar := filepath.Join(tempDir, instance.ID()+".tar")
-		err = engine.saveOneImage(instance.ID(), opts.Format, instanceTar, opts.Compress)
+		err = engine.saveOneImage(instance.ID(), format, instanceTar, compress)
 		if err != nil {
 			return err
 		}