feat: support ermerge packages analyzer

Signed-off-by: Lexus Lee <[email protected]>

Author: thehackercat

differs/differs.go

@@ -36,6 +36,7 @@ const rpmAnalyzer = "rpm"
 const rpmLayerAnalyzer = "rpmlayer"
 const pipAnalyzer = "pip"
 const nodeAnalyzer = "node"
+const emergeAnalyzer = "emerge"
 
 type DiffRequest struct {
 	Image1    pkgutil.Image
@@ -67,6 +68,7 @@ var Analyzers = map[string]Analyzer{
 	rpmLayerAnalyzer:  RPMLayerAnalyzer{},
 	pipAnalyzer:       PipAnalyzer{},
 	nodeAnalyzer:      NodeAnalyzer{},
+	emergeAnalyzer:    EmergeAnalyzer{},
 }
 
 var LayerAnalyzers = [...]string{layerAnalyzer, sizeLayerAnalyzer, aptLayerAnalyzer, rpmLayerAnalyzer}

differs/emerge_diff.go

@@ -0,0 +1,123 @@
+/*
+Copyright 2018 Google, Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package differs
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	pkgutil "github.com/GoogleContainerTools/container-diff/pkg/util"
+	"github.com/GoogleContainerTools/container-diff/util"
+	"github.com/sirupsen/logrus"
+)
+
+//Emerge package database location
+const emergePkgFile string = "/var/db/pkg"
+
+type EmergeAnalyzer struct {
+}
+
+func (em EmergeAnalyzer) Name() string {
+	return "EmergeAnalyzer"
+}
+
+// Diff compares the packages installed by emerge.
+func (em EmergeAnalyzer) Diff(image1, image2 pkgutil.Image) (util.Result, error) {
+	diff, err := singleVersionDiff(image1, image2, em)
+	return diff, err
+}
+
+func (em EmergeAnalyzer) Analyze(image pkgutil.Image) (util.Result, error) {
+	analysis, err := singleVersionAnalysis(image, em)
+	return analysis, err
+}
+
+func (em EmergeAnalyzer) getPackages(image pkgutil.Image) (map[string]util.PackageInfo, error) {
+	var path string
+	path = image.FSPath
+	switch path {
+	case "":
+		path = emergePkgFile
+	default:
+		path = filepath.Join(path, emergePkgFile)
+	}
+	packages := make(map[string]util.PackageInfo)
+	if _, err := os.Stat(path); err != nil {
+		// invalid image directory path
+		logrus.Errorf("Invalid image directory path %s", path)
+		return packages, err
+	}
+
+	contents, err := ioutil.ReadDir(path)
+	if err != nil {
+		logrus.Errorf("Non-content in image directory path %s", path)
+		return packages, err
+	}
+
+	for i := 0; i < len(contents); i++ {
+		c := contents[i]
+		pkgPrefix := c.Name()
+		pkgContents, err := ioutil.ReadDir(filepath.Join(path, pkgPrefix))
+		if err != nil {
+			return packages, err
+		}
+		for j := 0; j < len(pkgContents); j++ {
+			c := pkgContents[j]
+			pkgRawName := c.Name()
+			// in usual, name of package installed by emerge is formatted as '{pkgName}-{version}' e.g.(pymongo-3.9.0)
+			s := strings.Split(pkgRawName, "-")
+			if len(s) != 2 {
+				continue
+			}
+			pkgName, version := s[0], s[1]
+			pkgPath := filepath.Join(path, pkgPrefix, pkgRawName, "SIZE")
+			size, err := getPkgSize(pkgPath)
+			if err != nil {
+				return packages, err
+			}
+			currPackage := util.PackageInfo{Version: version, Size: size}
+			fullPackageName := strings.Join([]string{pkgPrefix, pkgName}, "/")
+			packages[fullPackageName] = currPackage
+		}
+	}
+
+	return packages, nil
+}
+
+// emerge will count the total size of a package and store it as a SIZE file in pkg metadata directory
+// getPkgSize read this SIZE file of a given package
+func getPkgSize(pkgPath string) (int64, error) {
+	var sizeFile *os.File
+	var err error
+	sizeFile, err = os.Open(pkgPath)
+	if err != nil {
+		logrus.Debugf("unable to open SIZE file for pkg %s", pkgPath)
+		return 0, err
+	}
+	defer sizeFile.Close()
+	fileBody, err := ioutil.ReadAll(sizeFile)
+	if err != nil {
+		logrus.Debugf("unable to read SIZE file for pkg %s", pkgPath)
+		return 0, err
+	}
+	strFileBody := strings.Replace(string(fileBody), "\n", "", -1)
+	size, _ := strconv.ParseInt(strFileBody, 10, 64)
+	return size, nil
+}

differs/emerge_diff_test.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2018 Google, Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package differs
+
+import (
+	"reflect"
+	"testing"
+
+	pkgutil "github.com/GoogleContainerTools/container-diff/pkg/util"
+	"github.com/GoogleContainerTools/container-diff/util"
+)
+
+func TestGetEmergePackages(t *testing.T) {
+	testCases := []struct {
+		descrip  string
+		path     string
+		expected map[string]util.PackageInfo
+		err      bool
+	}{
+		{
+			descrip:  "no directory",
+			path:     "testDirs/notThere",
+			expected: map[string]util.PackageInfo{},
+			err:      true,
+		},
+		{
+			descrip:  "no packages",
+			path:     "testDirs/noPackages",
+			expected: map[string]util.PackageInfo{},
+		},
+		{
+			descrip: "packages in expected location",
+			path:    "testDirs/packageEmerge",
+			expected: map[string]util.PackageInfo{
+				"dev-python/pkg1": {Version: "0.0.1", Size: 167112},
+				"dev-python/pkg2": {Version: "0.0.2", Size: 167112},
+				"sys-libs/pkg3":   {Version: "0.0.3", Size: 167112}},
+		},
+	}
+	for _, test := range testCases {
+		d := EmergeAnalyzer{}
+		image := pkgutil.Image{FSPath: test.path}
+		packages, err := d.getPackages(image)
+		if err != nil && !test.err {
+			t.Errorf("Got unexpected error: %s", err)
+		}
+		if err == nil && test.err {
+			t.Errorf("Expected error but got none.")
+		}
+		if !reflect.DeepEqual(packages, test.expected) {
+			t.Errorf("Expected: %v but got: %v", test.expected, packages)
+		}
+	}
+}

differs/testDirs/noPackages/var/db/pkg/dir/file

@@ -0,0 +1 @@
+167112

differs/testDirs/packageEmerge/var/db/pkg/dev-python/pkg1-0.0.1/SIZE

@@ -0,0 +1 @@
+167112

differs/testDirs/packageEmerge/var/db/pkg/dev-python/pkg2-0.0.2/SIZE

@@ -0,0 +1 @@
+167112