Add support for Alpine (apk)

differs/apk_diff.go

@@ -0,0 +1,167 @@
+/*
+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 (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	pkgutil "github.com/GoogleContainerTools/container-diff/pkg/util"
+	"github.com/GoogleContainerTools/container-diff/util"
+	"github.com/sirupsen/logrus"
+)
+
+// APK package database location
+const apkInstalledDbFile string = "lib/apk/db/installed"
+
+type ApkAnalyzer struct {
+}
+
+func (a ApkAnalyzer) Name() string {
+	return "ApkAnalyzer"
+}
+
+// ApkDiff compares the packages installed by apt-get.
+func (a ApkAnalyzer) Diff(image1, image2 pkgutil.Image) (util.Result, error) {
+	diff, err := singleVersionDiff(image1, image2, a)
+	return diff, err
+}
+
+func (a ApkAnalyzer) Analyze(image pkgutil.Image) (util.Result, error) {
+	analysis, err := singleVersionAnalysis(image, a)
+	return analysis, err
+}
+
+func (a ApkAnalyzer) getPackages(image pkgutil.Image) (map[string]util.PackageInfo, error) {
+	return apkReadInstalledDbFile(image.FSPath)
+}
+
+type ApkLayerAnalyzer struct {
+}
+
+func (a ApkLayerAnalyzer) Name() string {
+	return "ApkLayerAnalyzer"
+}
+
+// ApkDiff compares the packages installed by apt-get.
+func (a ApkLayerAnalyzer) Diff(image1, image2 pkgutil.Image) (util.Result, error) {
+	diff, err := singleVersionLayerDiff(image1, image2, a)
+	return diff, err
+}
+
+func (a ApkLayerAnalyzer) Analyze(image pkgutil.Image) (util.Result, error) {
+	analysis, err := singleVersionLayerAnalysis(image, a)
+	return analysis, err
+}
+
+func (a ApkLayerAnalyzer) getPackages(image pkgutil.Image) ([]map[string]util.PackageInfo, error) {
+	var packages []map[string]util.PackageInfo
+	if _, err := os.Stat(image.FSPath); err != nil {
+		// invalid image directory path
+		return packages, err
+	}
+	installedDbFile := filepath.Join(image.FSPath, apkInstalledDbFile)
+	if _, err := os.Stat(installedDbFile); err != nil {
+		// installed DB file does not exist in this image
+		return packages, nil
+	}
+	for _, layer := range image.Layers {
+		layerPackages, err := apkReadInstalledDbFile(layer.FSPath)
+		if err != nil {
+			return packages, err
+		}
+		packages = append(packages, layerPackages)
+	}
+
+	return packages, nil
+}
+
+func apkReadInstalledDbFile(root string) (map[string]util.PackageInfo, error) {
+	packages := make(map[string]util.PackageInfo)
+	if _, err := os.Stat(root); err != nil {
+		// invalid image directory path
+		return packages, err
+	}
+	installedDbFile := filepath.Join(root, apkInstalledDbFile)
+	if _, err := os.Stat(installedDbFile); err != nil {
+		// installed DB file does not exist in this layer
+		return packages, nil
+	}
+	if file, err := os.Open(installedDbFile); err == nil {
+		// make sure it gets closed
+		defer file.Close()
+
+		// create a new scanner and read the file line by line
+		scanner := bufio.NewScanner(file)
+		var currPackage string
+		for scanner.Scan() {
+			currPackage = apkParseLine(scanner.Text(), currPackage, packages)
+		}
+	} else {
+		return packages, err
+	}
+
+	return packages, nil
+}
+
+func apkParseLine(text string, currPackage string, packages map[string]util.PackageInfo) string {
+	line := strings.Split(text, ":")
+	if len(line) == 2 {
+		key := line[0]
+		value := line[1]
+
+		switch key {
+		case "P":
+			return value
+		case "V":
+			if packages[currPackage].Version != "" {
+				logrus.Warningln("Multiple versions of same package detected.  Diffing such multi-versioning not yet supported.")
+				return currPackage
+			}
+			currPackageInfo, ok := packages[currPackage]
+			if !ok {
+				currPackageInfo = util.PackageInfo{}
+			}
+			currPackageInfo.Version = value
+			packages[currPackage] = currPackageInfo
+			return currPackage
+
+		case "I":
+			currPackageInfo, ok := packages[currPackage]
+			if !ok {
+				currPackageInfo = util.PackageInfo{}
+			}
+			var size int64
+			var err error
+			size, err = strconv.ParseInt(value, 10, 64)
+			if err != nil {
+				logrus.Errorf("Could not get size for %s: %s", currPackage, err)
+				size = -1
+			}
+			// I is in bytes, so *no* conversion needed to keep consistent with the tool's size units
+			currPackageInfo.Size = size
+			packages[currPackage] = currPackageInfo
+			return currPackage
+		default:
+			return currPackage
+		}
+	}
+	return currPackage
+}

differs/apk_diff_test.go

@@ -0,0 +1,128 @@
+/*
+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 TestApkParseLine(t *testing.T) {
+	testCases := []struct {
+		description string
+		line        string
+		packages    map[string]util.PackageInfo
+		currPackage string
+		expPackage  string
+		expected    map[string]util.PackageInfo
+	}{
+		{
+			description: "Not applicable line",
+			line:        "G:garbage info",
+			packages:    map[string]util.PackageInfo{},
+			expPackage:  "",
+			expected:    map[string]util.PackageInfo{},
+		},
+		{
+			description: "Package line",
+			line:        "P:musl",
+			currPackage: "foo",
+			expPackage:  "musl",
+			packages:    map[string]util.PackageInfo{},
+			expected:    map[string]util.PackageInfo{},
+		},
+		{
+			description: "Version line",
+			line:        "V:1.2.2-r1",
+			packages:    map[string]util.PackageInfo{},
+			currPackage: "musl",
+			expPackage:  "musl",
+			expected:    map[string]util.PackageInfo{"musl": {Version: "1.2.2-r1"}},
+		},
+		{
+			description: "Size line",
+			line:        "I:622592",
+			packages:    map[string]util.PackageInfo{},
+			currPackage: "musl",
+			expPackage:  "musl",
+			expected:    map[string]util.PackageInfo{"musl": {Size: 622592}},
+		},
+		{
+			description: "Pre-existing PackageInfo struct",
+			line:        "I:622592",
+			packages:    map[string]util.PackageInfo{"musl": {Version: "1.2.2-r1"}},
+			currPackage: "musl",
+			expPackage:  "musl",
+			expected:    map[string]util.PackageInfo{"musl": {Version: "1.2.2-r1", Size: 622592}},
+		},
+	}
+
+	for _, test := range testCases {
+		currPackage := apkParseLine(test.line, test.currPackage, test.packages)
+		if currPackage != test.expPackage {
+			t.Errorf("Expected current package to be: %s, but got: %s.", test.expPackage, currPackage)
+		}
+		if !reflect.DeepEqual(test.packages, test.expected) {
+			t.Errorf("Expected: %v but got: %v", test.expected, test.packages)
+		}
+	}
+}
+
+func TestGetApkPackages(t *testing.T) {
+	testCases := []struct {
+		description string
+		path        string
+		expected    map[string]util.PackageInfo
+		err         bool
+	}{
+		{
+			description: "no directory",
+			path:        "testDirs/notThere",
+			expected:    map[string]util.PackageInfo{},
+			err:         true,
+		},
+		{
+			description: "no packages",
+			path:        "testDirs/noPackages",
+			expected:    map[string]util.PackageInfo{},
+		},
+		{
+			description: "packages in expected location",
+			path:        "testDirs/packageOne",
+			expected: map[string]util.PackageInfo{
+				"musl":    {Version: "1.2.2-r1", Size: 622592},
+				"busybox": {Version: "1.32.1-r7", Size: 946176}},
+		},
+	}
+	for _, test := range testCases {
+		d := ApkAnalyzer{}
+		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/differs.go

@@ -30,6 +30,8 @@ const fileAnalyzer = "file"
 const layerAnalyzer = "layer"
 const sizeAnalyzer = "size"
 const sizeLayerAnalyzer = "sizelayer"
+const apkAnalyzer = "apk"
+const apkLayerAnalyzer = "apklayer"
 const aptAnalyzer = "apt"
 const aptLayerAnalyzer = "aptlayer"
 const rpmAnalyzer = "rpm"
@@ -62,6 +64,8 @@ var Analyzers = map[string]Analyzer{
 	layerAnalyzer:     FileLayerAnalyzer{},
 	sizeAnalyzer:      SizeAnalyzer{},
 	sizeLayerAnalyzer: SizeLayerAnalyzer{},
+	apkAnalyzer:       ApkAnalyzer{},
+	apkLayerAnalyzer:  ApkLayerAnalyzer{},
 	aptAnalyzer:       AptAnalyzer{},
 	aptLayerAnalyzer:  AptLayerAnalyzer{},
 	rpmAnalyzer:       RPMAnalyzer{},

differs/testDirs/packageOne/lib/apk/db/installed

@@ -0,0 +1,78 @@
+C:Q1PLxH/xkzg+5Ny+Sid1STPEHi8e8=
+P:musl
+V:1.2.2-r1
+A:x86_64
+S:382799
+I:622592
+T:the musl c library (libc) implementation
+U:https://musl.libc.org/
+L:MIT
+o:musl
+m:Timo Teräs <timo.teras@iki.fi>
+t:1623058830
+c:bbbf656a5c008cd72af26290e7933a515af7f11f
+p:so:libc.musl-x86_64.so.1=1
+F:lib
+R:ld-musl-x86_64.so.1
+a:0:0:755
+Z:Q1YVYdCRbKnapM6sWXMBeIM5V6azc=
+R:libc.musl-x86_64.so.1
+a:0:0:777
+Z:Q17yJ3JFNypA4mxhJJr0ou6CzsJVI=
+
+C:Q1URbAAbfw05cknLVZMabtNfnjbtA=
+P:busybox
+V:1.32.1-r7
+A:x86_64
+S:497882
+I:946176
+T:Size optimized toolbox of many common UNIX utilities
+U:https://busybox.net/
+L:GPL-2.0-only
+o:busybox
+m:Natanael Copa <ncopa@alpinelinux.org>
+t:1636715120
+c:c434d5ff440c3e8bea3dbe139875e98a8c112202
+D:so:libc.musl-x86_64.so.1
+p:/bin/sh cmd:busybox cmd:sh
+r:busybox-initscripts
+F:bin
+R:busybox
+a:0:0:755
+Z:Q1PtQZENNCmILe4Zi742XWtTRj+iw=
+R:sh
+a:0:0:777
+Z:Q1pcfTfDNEbNKQc2s1tia7da05M8Q=
+F:etc
+R:securetty
+Z:Q1mB95Hq2NUTZ599RDiSsj9w5FrOU=
+R:udhcpd.conf
+Z:Q1UAiPZcDIW1ClRzobfggcCQ77V28=
+F:etc/logrotate.d
+R:acpid
+Z:Q1TylyCINVmnS+A/Tead4vZhE7Bks=
+F:etc/network
+F:etc/network/if-down.d
+F:etc/network/if-post-down.d
+F:etc/network/if-post-up.d
+F:etc/network/if-pre-down.d
+F:etc/network/if-pre-up.d
+F:etc/network/if-up.d
+R:dad
+a:0:0:775
+Z:Q1hlxd3qExrihH8bYxDQ3i7TsM/44=
+F:sbin
+F:tmp
+M:0:0:1777
+F:usr
+F:usr/sbin
+F:usr/share
+F:usr/share/udhcpc
+R:default.script
+a:0:0:755
+Z:Q1t9vir/ZrX3nbSIYT9BDLWZenkVQ=
+F:var
+F:var/cache
+F:var/cache/misc
+F:var/lib
+F:var/lib/udhcpd