Function newImageSource

sif/src.go:67–167

newImageSource returns an ImageSource for reading from an existing directory. newImageSource extracts SIF objects and saves them in a temp directory.

(ctx context.Context, sys *types.SystemContext, ref sifReference)

// newImageSource returns an ImageSource for reading from an existing directory.
// newImageSource extracts SIF objects and saves them in a temp directory.
func newImageSource(ctx context.Context, sys *types.SystemContext, ref sifReference) (private.ImageSource, error) {
	sifImg, err := sif.LoadContainerFromPath(ref.file, sif.OptLoadWithFlag(os.O_RDONLY))
	if err != nil {
		return nil, fmt.Errorf("loading SIF file: %w", err)
	}
	defer func() {
		_ = sifImg.UnloadContainer()
	}()

	workDir, err := tmpdir.MkDirBigFileTemp(sys, "sif")
	if err != nil {
		return nil, fmt.Errorf("creating temp directory: %w", err)
	}
	succeeded := false
	defer func() {
		if !succeeded {
			os.RemoveAll(workDir)
		}
	}()

	layerPath, commandLine, err := convertSIFToElements(ctx, sifImg, workDir)
	if err != nil {
		return nil, fmt.Errorf("converting rootfs from SquashFS to Tarball: %w", err)
	}

	layerDigest, layerSize, err := getBlobInfo(layerPath)
	if err != nil {
		return nil, fmt.Errorf("gathering blob information: %w", err)
	}

	created := sifImg.ModifiedAt()
	config := imgspecv1.Image{
		Created: &created,
		Platform: imgspecv1.Platform{
			Architecture: sifImg.PrimaryArch(),
			OS:           "linux",
		},
		Config: imgspecv1.ImageConfig{
			Cmd: commandLine,
		},
		RootFS: imgspecv1.RootFS{
			Type:    "layers",
			DiffIDs: []digest.Digest{layerDigest},
		},
		History: []imgspecv1.History{
			{
				Created:   &created,
				CreatedBy: fmt.Sprintf("/bin/sh -c #(nop) ADD file:%s in %c", layerDigest.Encoded(), os.PathSeparator),
				Comment:   "imported from SIF, uuid: " + sifImg.ID(),
			},
			{
				Created:    &created,
				CreatedBy:  "/bin/sh -c #(nop) CMD [\"bash\"]",
				EmptyLayer: true,
			},
		},
	}
	configBytes, err := json.Marshal(&config)