Switch to go mod

vendor/github.com/mudler/docker-companion/api/download.go

@@ -0,0 +1,155 @@
+package api
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/heroku/docker-registry-client/registry"
+	jww "github.com/spf13/jwalterweatherman"
+)
+
+const defaultRegistryBase = "https://registry-1.docker.io"
+
+type DownloadOpts struct {
+	RegistryBase string
+	KeepLayers   bool
+	UnpackMode   string
+}
+
+func DownloadAndUnpackImage(sourceImage, output string, opts *DownloadOpts) error {
+
+	if opts.RegistryBase == "" {
+		opts.RegistryBase = defaultRegistryBase
+	}
+
+	var TempDir = os.Getenv("TEMP_LAYER_FOLDER")
+	if TempDir == "" {
+		TempDir = "layers"
+	}
+	err := os.MkdirAll(TempDir, os.ModePerm)
+	if err != nil {
+		return err
+	}
+	if opts.KeepLayers == false {
+		defer os.RemoveAll(TempDir)
+	}
+
+	if sourceImage != "" && strings.Contains(sourceImage, ":") {
+		parts := strings.Split(sourceImage, ":")
+		if parts[0] == "" || parts[1] == "" {
+			return fmt.Errorf("Bad usage. Image should be in this format: foo/my-image:latest")
+		}
+	}
+
+	tagPart := "latest"
+	repoPart := sourceImage
+	parts := strings.Split(sourceImage, ":")
+	if len(parts) > 1 {
+		repoPart = parts[0]
+		tagPart = parts[1]
+	}
+
+	jww.INFO.Println("Unpacking", repoPart, "tag", tagPart, "in", output)
+	os.MkdirAll(output, os.ModePerm)
+	username := "" // anonymous
+	password := "" // anonymous
+	hub, err := registry.New(opts.RegistryBase, username, password)
+	if err != nil {
+		jww.ERROR.Fatalln(err)
+		return err
+	}
+	manifest, err := hub.Manifest(repoPart, tagPart)
+	if err != nil {
+		jww.ERROR.Fatalln(err)
+		return err
+	}
+	layers := manifest.FSLayers
+	layers_sha := make([]string, 0)
+	for _, l := range layers {
+		jww.INFO.Println("Layer ", l)
+		// or obtain the digest from an existing manifest's FSLayer list
+		s := string(l.BlobSum)
+		i := strings.Index(s, ":")
+		enc := s[i+1:]
+		reader, err := hub.DownloadBlob(repoPart, l.BlobSum)
+		layers_sha = append(layers_sha, enc)
+
+		if reader != nil {
+			defer reader.Close()
+		}
+		if err != nil {
+			return err
+		}
+
+		where := path.Join(TempDir, enc)
+		err = os.MkdirAll(where, os.ModePerm)
+		if err != nil {
+			jww.ERROR.Println(err)
+			return err
+		}
+
+		out, err := os.Create(path.Join(where, "layer.tar"))
+		if err != nil {
+			return err
+		}
+		defer out.Close()
+		if _, err := io.Copy(out, reader); err != nil {
+			fmt.Println(err)
+			return err
+		}
+	}
+
+	jww.INFO.Println("Download complete")
+
+	export, err := CreateExport(TempDir)
+	if err != nil {
+		fmt.Println(err)
+		return err
+	}
+
+	jww.INFO.Println("Unpacking...")
+
+	err = export.UnPackLayers(layers_sha, output, opts.UnpackMode)
+	if err != nil {
+		jww.INFO.Fatal(err)
+		return err
+	}
+
+	jww.INFO.Println("Done")
+	return nil
+}
+
+func CreateExport(layers string) (*Export, error) {
+
+	export := &Export{
+		Entries: map[string]*ExportedImage{},
+		Path:    layers,
+	}
+
+	dirs, err := ioutil.ReadDir(export.Path)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, dir := range dirs {
+
+		if !dir.IsDir() {
+			continue
+		}
+
+		entry := &ExportedImage{
+			Path:         filepath.Join(export.Path, dir.Name()),
+			LayerTarPath: filepath.Join(export.Path, dir.Name(), "layer.tar"),
+			LayerDirPath: filepath.Join(export.Path, dir.Name(), "layer"),
+		}
+
+		export.Entries[dir.Name()] = entry
+	}
+
+	return export, err
+}