podman-remote save [image]

Add the ability to save an image from the remote-host to the
remote-client.

Signed-off-by: baude <bbaude@redhat.com>

2 files changed, 93 insertions, 0 deletions

diff --git a/libpod/image/image.go b/libpod/image/image.go
index 028a795ea..547fb8994 100644
--- a/libpod/image/image.go
+++ b/libpod/image/image.go
@@ -5,14 +5,18 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"os"
 	"strings"
 	"syscall"
 	"time"
 
 	types2 "github.com/containernetworking/cni/pkg/types"
 	cp "github.com/containers/image/copy"
+	"github.com/containers/image/directory"
+	dockerarchive "github.com/containers/image/docker/archive"
 	"github.com/containers/image/docker/reference"
 	"github.com/containers/image/manifest"
+	ociarchive "github.com/containers/image/oci/archive"
 	is "github.com/containers/image/storage"
 	"github.com/containers/image/tarball"
 	"github.com/containers/image/transports"
@@ -26,6 +30,7 @@ import (
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/reexec"
 	digest "github.com/opencontainers/go-digest"
+	imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1"
 	ociv1 "github.com/opencontainers/image-spec/specs-go/v1"
 	opentracing "github.com/opentracing/opentracing-go"
 	"github.com/pkg/errors"
@@ -1084,3 +1089,65 @@ func (i *Image) Comment(ctx context.Context, manifestType string) (string, error
 	}
 	return ociv1Img.History[0].Comment, nil
 }
+
+// Save writes a container image to the filesystem
+func (i *Image) Save(ctx context.Context, source, format, output string, moreTags []string, quiet, compress bool) error {
+	var (
+		writer       io.Writer
+		destRef      types.ImageReference
+		manifestType string
+		err          error
+	)
+
+	if quiet {
+		writer = os.Stderr
+	}
+	switch format {
+	case "oci-archive":
+		destImageName := imageNameForSaveDestination(i, source)
+		destRef, err = ociarchive.NewReference(output, destImageName) // destImageName may be ""
+		if err != nil {
+			return errors.Wrapf(err, "error getting OCI archive ImageReference for (%q, %q)", output, destImageName)
+		}
+	case "oci-dir":
+		destRef, err = directory.NewReference(output)
+		if err != nil {
+			return errors.Wrapf(err, "error getting directory ImageReference for %q", output)
+		}
+		manifestType = imgspecv1.MediaTypeImageManifest
+	case "docker-dir":
+		destRef, err = directory.NewReference(output)
+		if err != nil {
+			return errors.Wrapf(err, "error getting directory ImageReference for %q", output)
+		}
+		manifestType = manifest.DockerV2Schema2MediaType
+	case "docker-archive", "":
+		dst := output
+		destImageName := imageNameForSaveDestination(i, source)
+		if destImageName != "" {
+			dst = fmt.Sprintf("%s:%s", dst, destImageName)
+		}
+		destRef, err = dockerarchive.ParseReference(dst) // FIXME? Add dockerarchive.NewReference
+		if err != nil {
+			return errors.Wrapf(err, "error getting Docker archive ImageReference for %q", dst)
+		}
+	default:
+		return errors.Errorf("unknown format option %q", format)
+	}
+	// supports saving multiple tags to the same tar archive
+	var additionaltags []reference.NamedTagged
+	if len(moreTags) > 0 {
+		additionaltags, err = GetAdditionalTags(moreTags)
+		if err != nil {
+			return err
+		}
+	}
+	if err := i.PushImageToReference(ctx, destRef, manifestType, "", "", writer, compress, SigningOptions{}, &DockerRegistryOptions{}, additionaltags); err != nil {
+		if err2 := os.Remove(output); err2 != nil {
+			logrus.Errorf("error deleting %q: %v", output, err)
+		}
+		return errors.Wrapf(err, "unable to save %q", source)
+	}
+
+	return nil
+}
diff --git a/libpod/image/utils.go b/libpod/image/utils.go
index 3585428ad..544796a4b 100644
--- a/libpod/image/utils.go
+++ b/libpod/image/utils.go
@@ -1,6 +1,7 @@
 package image
 
 import (
+	"fmt"
 	"io"
 	"net/url"
 	"regexp"
@@ -148,3 +149,28 @@ func IsValidImageURI(imguri string) (bool, error) {
 	}
 	return true, nil
 }
+
+// imageNameForSaveDestination returns a Docker-like reference appropriate for saving img,
+// which the user referred to as imgUserInput; or an empty string, if there is no appropriate
+// reference.
+func imageNameForSaveDestination(img *Image, imgUserInput string) string {
+	if strings.Contains(img.ID(), imgUserInput) {
+		return ""
+	}
+
+	prepend := ""
+	localRegistryPrefix := fmt.Sprintf("%s/", DefaultLocalRegistry)
+	if !strings.HasPrefix(imgUserInput, localRegistryPrefix) {
+		// we need to check if localhost was added to the image name in NewFromLocal
+		for _, name := range img.Names() {
+			// If the user is saving an image in the localhost registry,  getLocalImage need
+			// a name that matches the format localhost/<tag1>:<tag2> or localhost/<tag>:latest to correctly
+			// set up the manifest and save.
+			if strings.HasPrefix(name, localRegistryPrefix) && (strings.HasSuffix(name, imgUserInput) || strings.HasSuffix(name, fmt.Sprintf("%s:latest", imgUserInput))) {
+				prepend = localRegistryPrefix
+				break
+			}
+		}
+	}
+	return fmt.Sprintf("%s%s", prepend, imgUserInput)
+}