Merge pull request #164 from vrothberg/fix-remote-rpm

RPMAnalzyer: download absent `remote://` images

Author: nkubala

differs/rpm_diff.go

@@ -80,6 +80,7 @@ func (a RPMAnalyzer) getPackages(image pkgutil.Image) (map[string]util.PackageIn
 	if _, err := os.Stat(rpmBinary); err != nil {
 		rpmBinary = filepath.Join(path, "usr/bin/rpm")
 		if _, err = os.Stat(rpmBinary); err != nil {
+			logrus.Errorf("Could not detect RPM binary in unpacked image %s", image.Source)
 			return packages, nil
 		}
 	}
@@ -99,7 +100,7 @@ func rpmDataFromContainer(image pkgutil.Image) (map[string]util.PackageInfo, err
 
 	// if image is a tar archive, we need to load it
 	imageName := image.Source
-	if pkgutil.IsTar(imageName) {
+	if image.IsTar() {
 		// NOTE: all work below is only required for multilayer tar
 		// archives generated by `docker save`.  Flat file-system
 		// archives generated by `docker create` can just be imported
@@ -123,6 +124,33 @@ func rpmDataFromContainer(image pkgutil.Image) (map[string]util.PackageInfo, err
 
 		defer client.RemoveImage(imageName)
 		defer logrus.Infof("Removing image %s", imageName)
+	} else if image.IsCloud() {
+		// if it's a remote image we pull it unconditionally and avoid
+		// name/tag conflicts by pulling it via its sha256 digest
+		var buf bytes.Buffer
+		digest, err := image.GetRemoteDigest()
+		if err != nil {
+			return packages, err
+		}
+		imageName = image.GetName() + "@" + digest
+		logrus.Infof("Pulling remote image %s", imageName)
+		pullOpts := godocker.PullImageOptions{
+			Repository:   imageName,
+			OutputStream: &buf,
+		}
+		if err := client.PullImage(pullOpts, godocker.AuthConfiguration{}); err != nil {
+			return packages, fmt.Errorf("Error pulling remote image %s: %s", imageName, err)
+		}
+		// log PullImage() output in debug mode
+		if logrus.GetLevel() == logrus.DebugLevel {
+			// log each line separately for consistency
+			for _, out := range strings.Split(buf.String(), "\n") {
+				if len(out) > 0 {
+					logrus.Debug(out)
+				}
+			}
+		}
+		defer client.RemoveImage(imageName)
 	}
 
 	contConf := godocker.Config{

pkg/util/BUILD.bazel

@@ -19,6 +19,7 @@ go_library(
         "//vendor/github.com/containers/image/docker:go_default_library",
         "//vendor/github.com/containers/image/docker/daemon:go_default_library",
         "//vendor/github.com/containers/image/docker/tarfile:go_default_library",
+        "//vendor/github.com/containers/image/manifest:go_default_library",
         "//vendor/github.com/containers/image/pkg/compression:go_default_library",
         "//vendor/github.com/containers/image/types:go_default_library",
         "//vendor/github.com/docker/docker/client:go_default_library",

pkg/util/cloud_prepper.go

@@ -38,7 +38,9 @@ func (p CloudPrepper) GetSource() string {
 }
 
 func (p CloudPrepper) GetImage() (Image, error) {
-	return getImage(p)
+	image, err := getImage(p)
+	image.Type = ImageTypeCloud
+	return image, err
 }
 
 func (p CloudPrepper) GetFileSystem() (string, error) {

pkg/util/daemon_prepper.go

@@ -41,7 +41,9 @@ func (p DaemonPrepper) GetSource() string {
 }
 
 func (p DaemonPrepper) GetImage() (Image, error) {
-	return getImage(p)
+	image, err := getImage(p)
+	image.Type = ImageTypeDaemon
+	return image, err
 }
 
 func (p DaemonPrepper) GetFileSystem() (string, error) {

pkg/util/image_prep_utils.go

@@ -27,6 +27,8 @@ import (
 	"strings"
 
 	"github.com/GoogleCloudPlatform/container-diff/pkg/cache"
+	"github.com/containers/image/docker"
+	"github.com/containers/image/manifest"
 	"github.com/containers/image/pkg/compression"
 	"github.com/containers/image/types"
 	"github.com/sirupsen/logrus"
@@ -40,10 +42,43 @@ type Prepper interface {
 	GetSource() string
 }
 
+type ImageType int
+
+const (
+	ImageTypeTar ImageType = iota
+	ImageTypeDaemon
+	ImageTypeCloud
+)
+
 type Image struct {
 	Source string
 	FSPath string
 	Config ConfigSchema
+	Type   ImageType
+}
+
+func (i *Image) IsTar() bool {
+	return i.Type == ImageTypeTar
+}
+
+func (i *Image) IsDaemon() bool {
+	return i.Type == ImageTypeDaemon
+}
+
+func (i *Image) IsCloud() bool {
+	return i.Type == ImageTypeCloud
+}
+
+func (i *Image) GetRemoteDigest() (string, error) {
+	ref, err := docker.ParseReference("//" + i.Source)
+	if err != nil {
+		return "", err
+	}
+	return getDigestFromReference(ref, i.Source)
+}
+
+func (i *Image) GetName() string {
+	return strings.Split(i.Source, ":")[0]
 }
 
 type ImageHistoryItem struct {
@@ -167,6 +202,29 @@ func getFileSystemFromReference(ref types.ImageReference, imageName string, cach
 	return path, nil
 }
 
+func getDigestFromReference(ref types.ImageReference, source string) (string, error) {
+	img, err := ref.NewImage(nil)
+	if err != nil {
+		logrus.Errorf("Error referencing image %s from registry: %s", source, err)
+		return "", errors.New("Could not obtain image digest")
+	}
+	defer img.Close()
+
+	rawManifest, _, err := img.Manifest()
+	if err != nil {
+		logrus.Errorf("Error referencing image %s from registry: %s", source, err)
+		return "", errors.New("Could not obtain image digest")
+	}
+
+	digest, err := manifest.Digest(rawManifest)
+	if err != nil {
+		logrus.Errorf("Error referencing image %s from registry: %s", source, err)
+		return "", errors.New("Could not obtain image digest")
+	}
+
+	return digest.String(), nil
+}
+
 func getConfigFromReference(ref types.ImageReference, source string) (ConfigSchema, error) {
 	img, err := ref.NewImage(nil)
 	if err != nil {

pkg/util/tar_prepper.go

@@ -44,7 +44,9 @@ func (p TarPrepper) GetSource() string {
 }
 
 func (p TarPrepper) GetImage() (Image, error) {
-	return getImage(p)
+	image, err := getImage(p)
+	image.Type = ImageTypeTar
+	return image, err
 }
 
 func (p TarPrepper) GetFileSystem() (string, error) {