Add support for dir transport to kpod save

kpod save can now save images to directories using the
dir transport. Manifest conversion is also possible.
To save with the oci manifest type set --format to oci-dir
and to save with the v2s2(docker) manifest type, set --format
to docker-dir.
The layers can be compressed as well when saving to a directory
using the --compress flag.
Added functionality to kpod load to be able to load image from
a directory

Signed-off-by: umohnani8 <umohnani@redhat.com>

Closes: #137
Approved by: rhatdan

1 files changed, 31 insertions, 3 deletions

diff --git a/cmd/kpod/save.go b/cmd/kpod/save.go
index 0f5fcfa4d..85a8c7930 100644
--- a/cmd/kpod/save.go
+++ b/cmd/kpod/save.go
@@ -3,15 +3,27 @@ package main
 import (
 	"io"
 	"os"
+	"strings"
 
+	"github.com/containers/image/manifest"
+	imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"github.com/projectatomic/libpod/libpod"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli"
 )
 
+const (
+	ociManifestDir  = "oci-dir"
+	v2s2ManifestDir = "docker-dir"
+)
+
 var (
 	saveFlags = []cli.Flag{
+		cli.BoolFlag{
+			Name:  "compress",
+			Usage: "compress tarball image layers when saving to a directory using the 'dir' transport. (default is same compression type as source)",
+		},
 		cli.StringFlag{
 			Name:  "output, o",
 			Usage: "Write to a file, default is STDOUT",
@@ -23,7 +35,7 @@ var (
 		},
 		cli.StringFlag{
 			Name:  "format",
-			Usage: "Save image to oci-archive",
+			Usage: "Save image to oci-archive, oci-dir (directory with oci manifest type), docker-dir (directory with v2s2 manifest type)",
 		},
 	}
 	saveDescription = `
@@ -56,6 +68,10 @@ func saveCmd(c *cli.Context) error {
 	}
 	defer runtime.Shutdown(false)
 
+	if c.IsSet("compress") && (c.String("format") != ociManifestDir && c.String("format") != v2s2ManifestDir && c.String("format") == "") {
+		return errors.Errorf("--compress can only be set when --format is either 'oci-dir' or 'docker-dir'")
+	}
+
 	var writer io.Writer
 	if !c.Bool("quiet") {
 		writer = os.Stdout
@@ -69,10 +85,16 @@ func saveCmd(c *cli.Context) error {
 		}
 	}
 
-	var dst string
+	var dst, manifestType string
 	switch c.String("format") {
 	case libpod.OCIArchive:
 		dst = libpod.OCIArchive + ":" + output
+	case "oci-dir":
+		dst = libpod.DirTransport + ":" + output
+		manifestType = imgspecv1.MediaTypeImageManifest
+	case "docker-dir":
+		dst = libpod.DirTransport + ":" + output
+		manifestType = manifest.DockerV2Schema2MediaType
 	case libpod.DockerArchive:
 		fallthrough
 	case "":
@@ -84,12 +106,18 @@ func saveCmd(c *cli.Context) error {
 	saveOpts := libpod.CopyOptions{
 		SignaturePolicyPath: "",
 		Writer:              writer,
+		ManifestMIMEType:    manifestType,
+		ForceCompress:       c.Bool("compress"),
 	}
 
 	// only one image is supported for now
 	// future pull requests will fix this
 	for _, image := range args {
-		dest := dst + ":" + image
+		dest := dst
+		// need dest to be in the format transport:path:reference for the following transports
+		if strings.Contains(dst, libpod.OCIArchive) || strings.Contains(dst, libpod.DockerArchive) {
+			dest = dst + ":" + image
+		}
 		if err := runtime.PushImage(image, dest, saveOpts); err != nil {
 			if err2 := os.Remove(output); err2 != nil {
 				logrus.Errorf("error deleting %q: %v", output, err)