Add rpmlayer differ

This commit adds the rpmlayer differ that allows to perform analysis
at rpm package level on each layer. Lists new, deleted and modified
(different version) packages on each layer.

Signed-off-by: David Cassany <[email protected]>

Author: davidcassany

cmd/root.go

@@ -59,7 +59,7 @@ const (
 	RemotePrefix = "remote://"
 )
 
-var layerAnalyzers = [...]string{"layer", "aptlayer"}
+var layerAnalyzers = [...]string{"layer", "aptlayer", "rpmlayer"}
 
 var RootCmd = &cobra.Command{
 	Use:   "container-diff",

differs/differs.go

@@ -49,6 +49,7 @@ var Analyzers = map[string]Analyzer{
 	"apt":      AptAnalyzer{},
 	"aptlayer": AptLayerAnalyzer{},
 	"rpm":      RPMAnalyzer{},
+	"rpmlayer": RPMLayerAnalyzer{},
 	"pip":      PipAnalyzer{},
 	"node":     NodeAnalyzer{},
 }

differs/rpm_diff.go

@@ -34,6 +34,8 @@ import (
 	"github.com/google/go-containerregistry/pkg/name"
 	"github.com/google/go-containerregistry/pkg/v1"
 	"github.com/google/go-containerregistry/pkg/v1/daemon"
+	"github.com/google/go-containerregistry/pkg/v1/mutate"
+	"github.com/google/go-containerregistry/pkg/v1/random"
 
 	pkgutil "github.com/GoogleContainerTools/container-diff/pkg/util"
 	"github.com/GoogleContainerTools/container-diff/util"
@@ -101,7 +103,7 @@ func (a RPMAnalyzer) getPackages(image pkgutil.Image) (map[string]util.PackageIn
 	packages, err := rpmDataFromImageFS(image)
 	if err != nil {
 		logrus.Info("Running RPM binary from image in a container")
-		return rpmDataFromContainer(image)
+		return rpmDataFromContainer(image.Image)
 	}
 	return packages, err
 }
@@ -164,7 +166,7 @@ func rpmDBPath(rootFSPath string) (string, error) {
 
 // rpmDataFromContainer runs image in a container, queries the data of
 // installed rpm packages and returns a map of packages.
-func rpmDataFromContainer(image pkgutil.Image) (map[string]util.PackageInfo, error) {
+func rpmDataFromContainer(image v1.Image) (map[string]util.PackageInfo, error) {
 	packages := make(map[string]util.PackageInfo)
 
 	client, err := godocker.NewClientFromEnv()
@@ -175,7 +177,7 @@ func rpmDataFromContainer(image pkgutil.Image) (map[string]util.PackageInfo, err
 		return packages, err
 	}
 
-	imageName, err := loadImageToDaemon(image.Image)
+	imageName, err := loadImageToDaemon(image)
 
 	if err != nil {
 		return packages, fmt.Errorf("Error loading image: %s", err)
@@ -364,3 +366,115 @@ func unlock() error {
 	daemonMutex.Unlock()
 	return nil
 }
+
+type RPMLayerAnalyzer struct {
+}
+
+// Name returns the name of the analyzer.
+func (a RPMLayerAnalyzer) Name() string {
+	return "RPMLayerAnalyzer"
+}
+
+// Diff compares the installed rpm packages of image1 and image2 for each layer
+func (a RPMLayerAnalyzer) Diff(image1, image2 pkgutil.Image) (util.Result, error) {
+	diff, err := singleVersionLayerDiff(image1, image2, a)
+	return diff, err
+}
+
+// Analyze collects information of the installed rpm packages on each layer
+func (a RPMLayerAnalyzer) Analyze(image pkgutil.Image) (util.Result, error) {
+	analysis, err := singleVersionLayerAnalysis(image, a)
+	return analysis, err
+}
+
+// getPackages returns an array of maps of installed rpm packages on each layer
+func (a RPMLayerAnalyzer) getPackages(image pkgutil.Image) ([]map[string]util.PackageInfo, error) {
+	path := image.FSPath
+	var packages []map[string]util.PackageInfo
+	if _, err := os.Stat(path); err != nil {
+		// invalid image directory path
+		return packages, err
+	}
+
+	// try to find the rpm binary in bin/ or usr/bin/
+	rpmBinary := filepath.Join(path, "bin/rpm")
+	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
+		}
+	}
+
+	packages, err := rpmDataFromLayerFS(image)
+	if err != nil {
+		logrus.Info("Running RPM binary from image in a container")
+		return rpmDataFromLayeredContainers(image.Image)
+	}
+	return packages, err
+}
+
+// rpmDataFromLayerFS runs a local rpm binary, if any, to query the layer
+// rpmdb and returns an array of maps of installed packages.
+func rpmDataFromLayerFS(image pkgutil.Image) ([]map[string]util.PackageInfo, error) {
+	var packages []map[string]util.PackageInfo
+	// Check there is an executable rpm tool in host
+	if err := exec.Command("rpm", "--version").Run(); err != nil {
+		logrus.Warn("No RPM binary in host")
+		return packages, err
+	}
+	dbPath, err := rpmDBPath(image.FSPath)
+	if err != nil {
+		logrus.Warnf("Couldn't find RPM database: %s", err.Error())
+		return packages, err
+	}
+	for _, layer := range image.Layers {
+		layerPackages := make(map[string]util.PackageInfo)
+		//query only layers that include the rpm database
+		if _, err := os.Stat(filepath.Join(layer.FSPath, dbPath)); err == nil {
+			cmdArgs := append([]string{"--root", layer.FSPath, "--dbpath", dbPath}, rpmCmd[1:]...)
+			out, err := exec.Command(rpmCmd[0], cmdArgs...).Output()
+			if err != nil {
+				logrus.Warnf("RPM call failed: %s", err.Error())
+				return packages, err
+			}
+			layerPackages, err = parsePackageData(strings.Split(string(out), "\n"))
+			if err != nil {
+				return packages, err
+			}
+		}
+		packages = append(packages, layerPackages)
+	}
+
+	return packages, nil
+}
+
+// rpmDataFromLayeredContainers runs a tmp image in a container for each layer,
+// queries the data of installed rpm packages and returns an array of maps of
+// packages.
+func rpmDataFromLayeredContainers(image v1.Image) ([]map[string]util.PackageInfo, error) {
+	var packages []map[string]util.PackageInfo
+	tmpImage, err := random.Image(0, 0)
+	if err != nil {
+		return packages, err
+	}
+	layers, err := image.Layers()
+	if err != nil {
+		return packages, err
+	}
+	// Append layers one by one to an empty image and query rpm
+	// database on each iteration
+	for _, layer := range layers {
+		tmpImage, err = mutate.AppendLayers(tmpImage, layer)
+		if err != nil {
+			return packages, err
+		}
+		layerPackages, err := rpmDataFromContainer(tmpImage)
+		if err != nil {
+			return packages, err
+		}
+		packages = append(packages, layerPackages)
+	}
+
+	return packages, nil
+}