Reproducible add with flag

pkg/executor/build.go

@@ -224,7 +224,7 @@ func (s *stageBuilder) build() error {
 	}
 	// Take initial snapshot
 	t := timing.Start("Initial FS snapshot")
-	if err := s.snapshotter.Init(); err != nil {
+	if err := s.snapshotter.Init(s.opts.Reproducible); err != nil {
 		return err
 	}
 	timing.DefaultRun.Stop(t)
@@ -290,7 +290,7 @@ func (s *stageBuilder) takeSnapshot(files []string) (string, error) {
 	var err error
 	t := timing.Start("Snapshotting FS")
 	if files == nil || s.opts.SingleSnapshot {
-		snapshot, err = s.snapshotter.TakeSnapshotFS()
+		snapshot, err = s.snapshotter.TakeSnapshotFS(s.opts.Reproducible)
 	} else {
 		// Volumes are very weird. They get snapshotted in the next command.
 		files = append(files, util.Volumes()...)

pkg/snapshot/snapshot.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"path/filepath"
+	"sort"
 	"syscall"
 
 	"github.com/GoogleContainerTools/kaniko/pkg/timing"
@@ -47,8 +48,8 @@ func NewSnapshotter(l *LayeredMap, d string) *Snapshotter {
 }
 
 // Init initializes a new snapshotter
-func (s *Snapshotter) Init() error {
-	_, _, err := s.scanFullFilesystem()
+func (s *Snapshotter) Init(reproducible bool) error {
+	_, _, err := s.scanFullFilesystem(reproducible)
 	return err
 }
 
@@ -94,7 +95,7 @@ func (s *Snapshotter) TakeSnapshot(files []string) (string, error) {
 
 // TakeSnapshotFS takes a snapshot of the filesystem, avoiding directories in the whitelist, and creates
 // a tarball of the changed files.
-func (s *Snapshotter) TakeSnapshotFS() (string, error) {
+func (s *Snapshotter) TakeSnapshotFS(reproducible bool) (string, error) {
 	f, err := ioutil.TempFile(snapshotPathPrefix, "")
 	if err != nil {
 		return "", err
@@ -103,7 +104,7 @@ func (s *Snapshotter) TakeSnapshotFS() (string, error) {
 	t := util.NewTar(f)
 	defer t.Close()
 
-	filesToAdd, filesToWhiteOut, err := s.scanFullFilesystem()
+	filesToAdd, filesToWhiteOut, err := s.scanFullFilesystem(reproducible)
 	if err != nil {
 		return "", err
 	}
@@ -115,7 +116,7 @@ func (s *Snapshotter) TakeSnapshotFS() (string, error) {
 	return f.Name(), nil
 }
 
-func (s *Snapshotter) scanFullFilesystem() ([]string, []string, error) {
+func (s *Snapshotter) scanFullFilesystem(reproducible bool) ([]string, []string, error) {
 	logrus.Info("Taking snapshot of full filesystem...")
 
 	// Some of the operations that follow (e.g. hashing) depend on the file system being synced,
@@ -186,6 +187,10 @@ func (s *Snapshotter) scanFullFilesystem() ([]string, []string, error) {
 	// Also add parent directories to keep the permission of them correctly.
 	filesToAdd = filesWithParentDirs(filesToAdd)
 
+	if reproducible {
+		sort.Strings(filesToAdd)
+	}
+
 	// Add files to the layered map
 	for _, file := range filesToAdd {
 		if err := s.l.Add(file); err != nil {

pkg/snapshot/snapshot_test.go

@@ -44,7 +44,7 @@ func TestSnapshotFSFileChange(t *testing.T) {
 		t.Fatalf("Error setting up fs: %s", err)
 	}
 	// Take another snapshot
-	tarPath, err := snapshotter.TakeSnapshotFS()
+	tarPath, err := snapshotter.TakeSnapshotFS(false)
 	if err != nil {
 		t.Fatalf("Error taking snapshot of fs: %s", err)
 	}
@@ -87,6 +87,45 @@ func TestSnapshotFSFileChange(t *testing.T) {
 	}
 }
 
+func TestSnapshotFSIsReproducible(t *testing.T) {
+	testDir, snapshotter, cleanup, err := setUpTestDir()
+	defer cleanup()
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Make some changes to the filesystem
+	newFiles := map[string]string{
+		"foo":     "newbaz1",
+		"bar/bat": "baz",
+	}
+	if err := testutil.SetupFiles(testDir, newFiles); err != nil {
+		t.Fatalf("Error setting up fs: %s", err)
+	}
+	// Take another snapshot
+	tarPath, err := snapshotter.TakeSnapshotFS(true)
+	if err != nil {
+		t.Fatalf("Error taking snapshot of fs: %s", err)
+	}
+
+	f, err := os.Open(tarPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Check contents of the snapshot, make sure contents are sorted by name
+	tr := tar.NewReader(f)
+	var filesInTar []string
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		filesInTar = append(filesInTar, hdr.Name)
+	}
+	if !sort.StringsAreSorted(filesInTar) {
+		t.Fatalf("Expected the file in the tar archive were sorted, actual list was not sorted: %v", filesInTar)
+	}
+}
+
 func TestSnapshotFSChangePermissions(t *testing.T) {
 	testDir, snapshotter, cleanup, err := setUpTestDir()
 	defer cleanup()
@@ -99,7 +138,7 @@ func TestSnapshotFSChangePermissions(t *testing.T) {
 		t.Fatalf("Error changing permissions on %s: %v", batPath, err)
 	}
 	// Take another snapshot
-	tarPath, err := snapshotter.TakeSnapshotFS()
+	tarPath, err := snapshotter.TakeSnapshotFS(false)
 	if err != nil {
 		t.Fatalf("Error taking snapshot of fs: %s", err)
 	}
@@ -192,7 +231,7 @@ func TestEmptySnapshotFS(t *testing.T) {
 	defer cleanup()
 
 	// Take snapshot with no changes
-	tarPath, err := snapshotter.TakeSnapshotFS()
+	tarPath, err := snapshotter.TakeSnapshotFS(false)
 	if err != nil {
 		t.Fatalf("Error taking snapshot of fs: %s", err)
 	}
@@ -234,7 +273,7 @@ func setUpTestDir() (string, *Snapshotter, func(), error) {
 	// Take the initial snapshot
 	l := NewLayeredMap(util.Hasher(), util.CacheHasher())
 	snapshotter := NewSnapshotter(l, testDir)
-	if err := snapshotter.Init(); err != nil {
+	if err := snapshotter.Init(false); err != nil {
 		return "", nil, nil, errors.Wrap(err, "initializing snapshotter")
 	}