Merge pull request #4705 from MichaelEischer/snapshot-statistics

Store snapshot statistics & print snapshot size

internal/archiver/archiver.go

@@ -8,6 +8,7 @@ import (
 	"runtime"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/restic/restic/internal/debug"
@@ -41,6 +42,18 @@ type ItemStats struct {
 	TreeSizeInRepo uint64 // sum of the bytes added to the repo (including compression and crypto overhead)
 }
 
+type ChangeStats struct {
+	New       uint
+	Changed   uint
+	Unchanged uint
+}
+
+type Summary struct {
+	Files, Dirs    ChangeStats
+	ProcessedBytes uint64
+	ItemStats
+}
+
 // Add adds other to the current ItemStats.
 func (s *ItemStats) Add(other ItemStats) {
 	s.DataBlobs += other.DataBlobs
@@ -62,6 +75,8 @@ type Archiver struct {
 	blobSaver *BlobSaver
 	fileSaver *FileSaver
 	treeSaver *TreeSaver
+	mu        sync.Mutex
+	summary   *Summary
 
 	// Error is called for all errors that occur during backup.
 	Error ErrorFunc
@@ -183,6 +198,44 @@ func (arch *Archiver) error(item string, err error) error {
 	return errf
 }
 
+func (arch *Archiver) trackItem(item string, previous, current *restic.Node, s ItemStats, d time.Duration) {
+	arch.CompleteItem(item, previous, current, s, d)
+
+	arch.mu.Lock()
+	defer arch.mu.Unlock()
+
+	arch.summary.ItemStats.Add(s)
+
+	if current != nil {
+		arch.summary.ProcessedBytes += current.Size
+	} else {
+		// last item or an error occurred
+		return
+	}
+
+	switch current.Type {
+	case "dir":
+		switch {
+		case previous == nil:
+			arch.summary.Dirs.New++
+		case previous.Equals(*current):
+			arch.summary.Dirs.Unchanged++
+		default:
+			arch.summary.Dirs.Changed++
+		}
+
+	case "file":
+		switch {
+		case previous == nil:
+			arch.summary.Files.New++
+		case previous.Equals(*current):
+			arch.summary.Files.Unchanged++
+		default:
+			arch.summary.Files.Changed++
+		}
+	}
+}
+
 // nodeFromFileInfo returns the restic node from an os.FileInfo.
 func (arch *Archiver) nodeFromFileInfo(snPath, filename string, fi os.FileInfo) (*restic.Node, error) {
 	node, err := restic.NodeFromFileInfo(filename, fi)
@@ -231,9 +284,9 @@ func (arch *Archiver) wrapLoadTreeError(id restic.ID, err error) error {
 	return err
 }
 
-// SaveDir stores a directory in the repo and returns the node. snPath is the
+// saveDir stores a directory in the repo and returns the node. snPath is the
 // path within the current snapshot.
-func (arch *Archiver) SaveDir(ctx context.Context, snPath string, dir string, fi os.FileInfo, previous *restic.Tree, complete CompleteFunc) (d FutureNode, err error) {
+func (arch *Archiver) saveDir(ctx context.Context, snPath string, dir string, fi os.FileInfo, previous *restic.Tree, complete CompleteFunc) (d FutureNode, err error) {
 	debug.Log("%v %v", snPath, dir)
 
 	treeNode, err := arch.nodeFromFileInfo(snPath, dir, fi)
@@ -259,7 +312,7 @@ func (arch *Archiver) SaveDir(ctx context.Context, snPath string, dir string, fi
 		pathname := arch.FS.Join(dir, name)
 		oldNode := previous.Find(name)
 		snItem := join(snPath, name)
-		fn, excluded, err := arch.Save(ctx, snItem, pathname, oldNode)
+		fn, excluded, err := arch.save(ctx, snItem, pathname, oldNode)
 
 		// return error early if possible
 		if err != nil {
@@ -343,14 +396,14 @@ func (arch *Archiver) allBlobsPresent(previous *restic.Node) bool {
 	return true
 }
 
-// Save saves a target (file or directory) to the repo. If the item is
+// save saves a target (file or directory) to the repo. If the item is
 // excluded, this function returns a nil node and error, with excluded set to
 // true.
 //
 // Errors and completion needs to be handled by the caller.
 //
 // snPath is the path within the current snapshot.
-func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous *restic.Node) (fn FutureNode, excluded bool, err error) {
+func (arch *Archiver) save(ctx context.Context, snPath, target string, previous *restic.Node) (fn FutureNode, excluded bool, err error) {
 	start := time.Now()
 
 	debug.Log("%v target %q, previous %v", snPath, target, previous)
@@ -389,7 +442,7 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
 		if previous != nil && !fileChanged(fi, previous, arch.ChangeIgnoreFlags) {
 			if arch.allBlobsPresent(previous) {
 				debug.Log("%v hasn't changed, using old list of blobs", target)
-				arch.CompleteItem(snPath, previous, previous, ItemStats{}, time.Since(start))
+				arch.trackItem(snPath, previous, previous, ItemStats{}, time.Since(start))
 				arch.CompleteBlob(previous.Size)
 				node, err := arch.nodeFromFileInfo(snPath, target, fi)
 				if err != nil {
@@ -454,9 +507,9 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
 		fn = arch.fileSaver.Save(ctx, snPath, target, file, fi, func() {
 			arch.StartFile(snPath)
 		}, func() {
-			arch.CompleteItem(snPath, nil, nil, ItemStats{}, 0)
+			arch.trackItem(snPath, nil, nil, ItemStats{}, 0)
 		}, func(node *restic.Node, stats ItemStats) {
-			arch.CompleteItem(snPath, previous, node, stats, time.Since(start))
+			arch.trackItem(snPath, previous, node, stats, time.Since(start))
 		})
 
 	case fi.IsDir():
@@ -471,9 +524,9 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
 			return FutureNode{}, false, err
 		}
 
-		fn, err = arch.SaveDir(ctx, snPath, target, fi, oldSubtree,
+		fn, err = arch.saveDir(ctx, snPath, target, fi, oldSubtree,
 			func(node *restic.Node, stats ItemStats) {
-				arch.CompleteItem(snItem, previous, node, stats, time.Since(start))
+				arch.trackItem(snItem, previous, node, stats, time.Since(start))
 			})
 		if err != nil {
 			debug.Log("SaveDir for %v returned error: %v", snPath, err)
@@ -554,9 +607,9 @@ func (arch *Archiver) statDir(dir string) (os.FileInfo, error) {
 	return fi, nil
 }
 
-// SaveTree stores a Tree in the repo, returned is the tree. snPath is the path
+// saveTree stores a Tree in the repo, returned is the tree. snPath is the path
 // within the current snapshot.
-func (arch *Archiver) SaveTree(ctx context.Context, snPath string, atree *Tree, previous *restic.Tree, complete CompleteFunc) (FutureNode, int, error) {
+func (arch *Archiver) saveTree(ctx context.Context, snPath string, atree *Tree, previous *restic.Tree, complete CompleteFunc) (FutureNode, int, error) {
 
 	var node *restic.Node
 	if snPath != "/" {
@@ -594,7 +647,7 @@ func (arch *Archiver) SaveTree(ctx context.Context, snPath string, atree *Tree,
 
 		// this is a leaf node
 		if subatree.Leaf() {
-			fn, excluded, err := arch.Save(ctx, join(snPath, name), subatree.Path, previous.Find(name))
+			fn, excluded, err := arch.save(ctx, join(snPath, name), subatree.Path, previous.Find(name))
 
 			if err != nil {
 				err = arch.error(subatree.Path, err)
@@ -628,8 +681,8 @@ func (arch *Archiver) SaveTree(ctx context.Context, snPath string, atree *Tree,
 		}
 
 		// not a leaf node, archive subtree
-		fn, _, err := arch.SaveTree(ctx, join(snPath, name), &subatree, oldSubtree, func(n *restic.Node, is ItemStats) {
-			arch.CompleteItem(snItem, oldNode, n, is, time.Since(start))
+		fn, _, err := arch.saveTree(ctx, join(snPath, name), &subatree, oldSubtree, func(n *restic.Node, is ItemStats) {
+			arch.trackItem(snItem, oldNode, n, is, time.Since(start))
 		})
 		if err != nil {
 			return FutureNode{}, 0, err
@@ -697,6 +750,7 @@ type SnapshotOptions struct {
 	Tags           restic.TagList
 	Hostname       string
 	Excludes       []string
+	BackupStart    time.Time
 	Time           time.Time
 	ParentSnapshot *restic.Snapshot
 	ProgramVersion string
@@ -747,15 +801,17 @@ func (arch *Archiver) stopWorkers() {
 }
 
 // Snapshot saves several targets and returns a snapshot.
-func (arch *Archiver) Snapshot(ctx context.Context, targets []string, opts SnapshotOptions) (*restic.Snapshot, restic.ID, error) {
+func (arch *Archiver) Snapshot(ctx context.Context, targets []string, opts SnapshotOptions) (*restic.Snapshot, restic.ID, *Summary, error) {
+	arch.summary = &Summary{}
+
 	cleanTargets, err := resolveRelativeTargets(arch.FS, targets)
 	if err != nil {
-		return nil, restic.ID{}, err
+		return nil, restic.ID{}, nil, err
 	}
 
 	atree, err := NewTree(arch.FS, cleanTargets)
 	if err != nil {
-		return nil, restic.ID{}, err
+		return nil, restic.ID{}, nil, err
 	}
 
 	var rootTreeID restic.ID
@@ -771,8 +827,8 @@ func (arch *Archiver) Snapshot(ctx context.Context, targets []string, opts Snaps
 			arch.runWorkers(wgCtx, wg)
 
 			debug.Log("starting snapshot")
-			fn, nodeCount, err := arch.SaveTree(wgCtx, "/", atree, arch.loadParentTree(wgCtx, opts.ParentSnapshot), func(_ *restic.Node, is ItemStats) {
-				arch.CompleteItem("/", nil, nil, is, time.Since(start))
+			fn, nodeCount, err := arch.saveTree(wgCtx, "/", atree, arch.loadParentTree(wgCtx, opts.ParentSnapshot), func(_ *restic.Node, is ItemStats) {
+				arch.trackItem("/", nil, nil, is, time.Since(start))
 			})
 			if err != nil {
 				return err
@@ -808,12 +864,12 @@ func (arch *Archiver) Snapshot(ctx context.Context, targets []string, opts Snaps
 	})
 	err = wgUp.Wait()
 	if err != nil {
-		return nil, restic.ID{}, err
+		return nil, restic.ID{}, nil, err
 	}
 
 	sn, err := restic.NewSnapshot(targets, opts.Tags, opts.Hostname, opts.Time)
 	if err != nil {
-		return nil, restic.ID{}, err
+		return nil, restic.ID{}, nil, err
 	}
 
 	sn.ProgramVersion = opts.ProgramVersion
@@ -822,11 +878,28 @@ func (arch *Archiver) Snapshot(ctx context.Context, targets []string, opts Snaps
 		sn.Parent = opts.ParentSnapshot.ID()
 	}
 	sn.Tree = &rootTreeID
+	sn.Summary = &restic.SnapshotSummary{
+		BackupStart: opts.BackupStart,
+		BackupEnd:   time.Now(),
+
+		FilesNew:            arch.summary.Files.New,
+		FilesChanged:        arch.summary.Files.Changed,
+		FilesUnmodified:     arch.summary.Files.Unchanged,
+		DirsNew:             arch.summary.Dirs.New,
+		DirsChanged:         arch.summary.Dirs.Changed,
+		DirsUnmodified:      arch.summary.Dirs.Unchanged,
+		DataBlobs:           arch.summary.ItemStats.DataBlobs,
+		TreeBlobs:           arch.summary.ItemStats.TreeBlobs,
+		DataAdded:           arch.summary.ItemStats.DataSize + arch.summary.ItemStats.TreeSize,
+		DataAddedPacked:     arch.summary.ItemStats.DataSizeInRepo + arch.summary.ItemStats.TreeSizeInRepo,
+		TotalFilesProcessed: arch.summary.Files.New + arch.summary.Files.Changed + arch.summary.Files.Unchanged,
+		TotalBytesProcessed: arch.summary.ProcessedBytes,
+	}
 
 	id, err := restic.SaveSnapshot(ctx, arch.Repo, sn)
 	if err != nil {
-		return nil, restic.ID{}, err
+		return nil, restic.ID{}, nil, err
 	}
 
-	return sn, id, nil
+	return sn, id, arch.summary, nil
 }

internal/archiver/archiver_test.go

@@ -227,8 +227,9 @@ func TestArchiverSave(t *testing.T) {
 				return err
 			}
 			arch.runWorkers(ctx, wg)
+			arch.summary = &Summary{}
 
-			node, excluded, err := arch.Save(ctx, "/", filepath.Join(tempdir, "file"), nil)
+			node, excluded, err := arch.save(ctx, "/", filepath.Join(tempdir, "file"), nil)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -304,8 +305,9 @@ func TestArchiverSaveReaderFS(t *testing.T) {
 				return err
 			}
 			arch.runWorkers(ctx, wg)
+			arch.summary = &Summary{}
 
-			node, excluded, err := arch.Save(ctx, "/", filename, nil)
+			node, excluded, err := arch.save(ctx, "/", filename, nil)
 			t.Logf("Save returned %v %v", node, err)
 			if err != nil {
 				t.Fatal(err)
@@ -832,6 +834,7 @@ func TestArchiverSaveDir(t *testing.T) {
 
 			arch := New(repo, fs.Track{FS: fs.Local{}}, Options{})
 			arch.runWorkers(ctx, wg)
+			arch.summary = &Summary{}
 
 			chdir := tempdir
 			if test.chdir != "" {
@@ -846,7 +849,7 @@ func TestArchiverSaveDir(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			ft, err := arch.SaveDir(ctx, "/", test.target, fi, nil, nil)
+			ft, err := arch.saveDir(ctx, "/", test.target, fi, nil, nil)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -913,13 +916,14 @@ func TestArchiverSaveDirIncremental(t *testing.T) {
 
 		arch := New(repo, fs.Track{FS: fs.Local{}}, Options{})
 		arch.runWorkers(ctx, wg)
+		arch.summary = &Summary{}
 
 		fi, err := fs.Lstat(tempdir)
 		if err != nil {
 			t.Fatal(err)
 		}
 
-		ft, err := arch.SaveDir(ctx, "/", tempdir, fi, nil, nil)
+		ft, err := arch.saveDir(ctx, "/", tempdir, fi, nil, nil)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -983,9 +987,9 @@ func TestArchiverSaveDirIncremental(t *testing.T) {
 
 // bothZeroOrNeither fails the test if only one of exp, act is zero.
 func bothZeroOrNeither(tb testing.TB, exp, act uint64) {
+	tb.Helper()
 	if (exp == 0 && act != 0) || (exp != 0 && act == 0) {
-		_, file, line, _ := runtime.Caller(1)
-		tb.Fatalf("\033[31m%s:%d:\n\n\texp: %#v\n\n\tgot: %#v\033[39m\n\n", filepath.Base(file), line, exp, act)
+		restictest.Equals(tb, exp, act)
 	}
 }
 
@@ -1005,7 +1009,7 @@ func TestArchiverSaveTree(t *testing.T) {
 		prepare func(t testing.TB)
 		targets []string
 		want    TestDir
-		stat    ItemStats
+		stat    Summary
 	}{
 		{
 			src: TestDir{
@@ -1015,7 +1019,12 @@ func TestArchiverSaveTree(t *testing.T) {
 			want: TestDir{
 				"targetfile": TestFile{Content: string("foobar")},
 			},
-			stat: ItemStats{1, 6, 32 + 6, 0, 0, 0},
+			stat: Summary{
+				ItemStats:      ItemStats{1, 6, 32 + 6, 0, 0, 0},
+				ProcessedBytes: 6,
+				Files:          ChangeStats{1, 0, 0},
+				Dirs:           ChangeStats{0, 0, 0},
+			},
 		},
 		{
 			src: TestDir{
@@ -1027,7 +1036,12 @@ func TestArchiverSaveTree(t *testing.T) {
 				"targetfile":  TestFile{Content: string("foobar")},
 				"filesymlink": TestSymlink{Target: "targetfile"},
 			},
-			stat: ItemStats{1, 6, 32 + 6, 0, 0, 0},
+			stat: Summary{
+				ItemStats:      ItemStats{1, 6, 32 + 6, 0, 0, 0},
+				ProcessedBytes: 6,
+				Files:          ChangeStats{1, 0, 0},
+				Dirs:           ChangeStats{0, 0, 0},
+			},
 		},
 		{
 			src: TestDir{
@@ -1047,7 +1061,12 @@ func TestArchiverSaveTree(t *testing.T) {
 					"symlink": TestSymlink{Target: "subdir"},
 				},
 			},
-			stat: ItemStats{0, 0, 0, 1, 0x154, 0x16a},
+			stat: Summary{
+				ItemStats:      ItemStats{0, 0, 0, 1, 0x154, 0x16a},
+				ProcessedBytes: 0,
+				Files:          ChangeStats{0, 0, 0},
+				Dirs:           ChangeStats{1, 0, 0},
+			},
 		},
 		{
 			src: TestDir{
@@ -1071,7 +1090,12 @@ func TestArchiverSaveTree(t *testing.T) {
 					},
 				},
 			},
-			stat: ItemStats{1, 6, 32 + 6, 3, 0x47f, 0x4c1},
+			stat: Summary{
+				ItemStats:      ItemStats{1, 6, 32 + 6, 3, 0x47f, 0x4c1},
+				ProcessedBytes: 6,
+				Files:          ChangeStats{1, 0, 0},
+				Dirs:           ChangeStats{3, 0, 0},
+			},
 		},
 	}
 
@@ -1083,18 +1107,11 @@ func TestArchiverSaveTree(t *testing.T) {
 
 			arch := New(repo, testFS, Options{})
 
-			var stat ItemStats
-			lock := &sync.Mutex{}
-			arch.CompleteItem = func(item string, previous, current *restic.Node, s ItemStats, d time.Duration) {
-				lock.Lock()
-				defer lock.Unlock()
-				stat.Add(s)
-			}
-
 			wg, ctx := errgroup.WithContext(context.TODO())
 			repo.StartPackUploader(ctx, wg)
 
 			arch.runWorkers(ctx, wg)
+			arch.summary = &Summary{}
 
 			back := restictest.Chdir(t, tempdir)
 			defer back()
@@ -1108,7 +1125,7 @@ func TestArchiverSaveTree(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			fn, _, err := arch.SaveTree(ctx, "/", atree, nil, nil)
+			fn, _, err := arch.saveTree(ctx, "/", atree, nil, nil)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -1135,11 +1152,15 @@ func TestArchiverSaveTree(t *testing.T) {
 				want = test.src
 			}
 			TestEnsureTree(context.TODO(), t, "/", repo, treeID, want)
+			stat := arch.summary
 			bothZeroOrNeither(t, uint64(test.stat.DataBlobs), uint64(stat.DataBlobs))
 			bothZeroOrNeither(t, uint64(test.stat.TreeBlobs), uint64(stat.TreeBlobs))
 			bothZeroOrNeither(t, test.stat.DataSize, stat.DataSize)
 			bothZeroOrNeither(t, test.stat.DataSizeInRepo, stat.DataSizeInRepo)
 			bothZeroOrNeither(t, test.stat.TreeSizeInRepo, stat.TreeSizeInRepo)
+			restictest.Equals(t, test.stat.ProcessedBytes, stat.ProcessedBytes)
+			restictest.Equals(t, test.stat.Files, stat.Files)
+			restictest.Equals(t, test.stat.Dirs, stat.Dirs)
 		})
 	}
 }
@@ -1396,7 +1417,7 @@ func TestArchiverSnapshot(t *testing.T) {
 			}
 
 			t.Logf("targets: %v", targets)
-			sn, snapshotID, err := arch.Snapshot(ctx, targets, SnapshotOptions{Time: time.Now()})
+			sn, snapshotID, _, err := arch.Snapshot(ctx, targets, SnapshotOptions{Time: time.Now()})
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -1544,7 +1565,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 			defer back()
 
 			targets := []string{"."}
-			_, snapshotID, err := arch.Snapshot(ctx, targets, SnapshotOptions{Time: time.Now()})
+			_, snapshotID, _, err := arch.Snapshot(ctx, targets, SnapshotOptions{Time: time.Now()})
 			if test.err != "" {
 				if err == nil {
 					t.Fatalf("expected error not found, got %v, wanted %q", err, test.err)
@@ -1617,17 +1638,85 @@ func (f MockFile) Read(p []byte) (int, error) {
 	return n, err
 }
 
+func checkSnapshotStats(t *testing.T, sn *restic.Snapshot, stat Summary) {
+	restictest.Equals(t, stat.Files.New, sn.Summary.FilesNew)
+	restictest.Equals(t, stat.Files.Changed, sn.Summary.FilesChanged)
+	restictest.Equals(t, stat.Files.Unchanged, sn.Summary.FilesUnmodified)
+	restictest.Equals(t, stat.Dirs.New, sn.Summary.DirsNew)
+	restictest.Equals(t, stat.Dirs.Changed, sn.Summary.DirsChanged)
+	restictest.Equals(t, stat.Dirs.Unchanged, sn.Summary.DirsUnmodified)
+	restictest.Equals(t, stat.ProcessedBytes, sn.Summary.TotalBytesProcessed)
+	restictest.Equals(t, stat.Files.New+stat.Files.Changed+stat.Files.Unchanged, sn.Summary.TotalFilesProcessed)
+	bothZeroOrNeither(t, uint64(stat.DataBlobs), uint64(sn.Summary.DataBlobs))
+	bothZeroOrNeither(t, uint64(stat.TreeBlobs), uint64(sn.Summary.TreeBlobs))
+	bothZeroOrNeither(t, uint64(stat.DataSize+stat.TreeSize), uint64(sn.Summary.DataAdded))
+	bothZeroOrNeither(t, uint64(stat.DataSizeInRepo+stat.TreeSizeInRepo), uint64(sn.Summary.DataAddedPacked))
+}
+
 func TestArchiverParent(t *testing.T) {
 	var tests = []struct {
-		src  TestDir
-		read map[string]int // tracks number of times a file must have been read
+		src         TestDir
+		modify      func(path string)
+		statInitial Summary
+		statSecond  Summary
 	}{
 		{
 			src: TestDir{
 				"targetfile": TestFile{Content: string(restictest.Random(888, 2*1024*1024+5000))},
 			},
-			read: map[string]int{
-				"targetfile": 1,
+			statInitial: Summary{
+				Files:          ChangeStats{1, 0, 0},
+				Dirs:           ChangeStats{0, 0, 0},
+				ProcessedBytes: 2102152,
+				ItemStats:      ItemStats{3, 0x201593, 0x201632, 1, 0, 0},
+			},
+			statSecond: Summary{
+				Files:          ChangeStats{0, 0, 1},
+				Dirs:           ChangeStats{0, 0, 0},
+				ProcessedBytes: 2102152,
+			},
+		},
+		{
+			src: TestDir{
+				"targetDir": TestDir{
+					"targetfile":  TestFile{Content: string(restictest.Random(888, 1234))},
+					"targetfile2": TestFile{Content: string(restictest.Random(888, 1235))},
+				},
+			},
+			statInitial: Summary{
+				Files:          ChangeStats{2, 0, 0},
+				Dirs:           ChangeStats{1, 0, 0},
+				ProcessedBytes: 2469,
+				ItemStats:      ItemStats{2, 0xe1c, 0xcd9, 2, 0, 0},
+			},
+			statSecond: Summary{
+				Files:          ChangeStats{0, 0, 2},
+				Dirs:           ChangeStats{0, 0, 1},
+				ProcessedBytes: 2469,
+			},
+		},
+		{
+			src: TestDir{
+				"targetDir": TestDir{
+					"targetfile": TestFile{Content: string(restictest.Random(888, 1234))},
+				},
+				"targetfile2": TestFile{Content: string(restictest.Random(888, 1235))},
+			},
+			modify: func(path string) {
+				remove(t, filepath.Join(path, "targetDir", "targetfile"))
+				save(t, filepath.Join(path, "targetfile2"), []byte("foobar"))
+			},
+			statInitial: Summary{
+				Files:          ChangeStats{2, 0, 0},
+				Dirs:           ChangeStats{1, 0, 0},
+				ProcessedBytes: 2469,
+				ItemStats:      ItemStats{2, 0xe13, 0xcf8, 2, 0, 0},
+			},
+			statSecond: Summary{
+				Files:          ChangeStats{0, 1, 0},
+				Dirs:           ChangeStats{0, 1, 0},
+				ProcessedBytes: 6,
+				ItemStats:      ItemStats{1, 0x305, 0x233, 2, 0, 0},
 			},
 		},
 	}
@@ -1649,7 +1738,7 @@ func TestArchiverParent(t *testing.T) {
 			back := restictest.Chdir(t, tempdir)
 			defer back()
 
-			firstSnapshot, firstSnapshotID, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
+			firstSnapshot, firstSnapshotID, summary, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -1674,33 +1763,33 @@ func TestArchiverParent(t *testing.T) {
 				}
 				return nil
 			})
+			restictest.Equals(t, test.statInitial.Files, summary.Files)
+			restictest.Equals(t, test.statInitial.Dirs, summary.Dirs)
+			restictest.Equals(t, test.statInitial.ProcessedBytes, summary.ProcessedBytes)
+			checkSnapshotStats(t, firstSnapshot, test.statInitial)
+
+			if test.modify != nil {
+				test.modify(tempdir)
+			}
 
 			opts := SnapshotOptions{
 				Time:           time.Now(),
 				ParentSnapshot: firstSnapshot,
 			}
-			_, secondSnapshotID, err := arch.Snapshot(ctx, []string{"."}, opts)
+			testFS.bytesRead = map[string]int{}
+			secondSnapshot, secondSnapshotID, summary, err := arch.Snapshot(ctx, []string{"."}, opts)
 			if err != nil {
 				t.Fatal(err)
 			}
 
-			// check that all files still been read exactly once
-			TestWalkFiles(t, ".", test.src, func(filename string, item interface{}) error {
-				file, ok := item.(TestFile)
-				if !ok {
-					return nil
-				}
-
-				n, ok := testFS.bytesRead[filename]
-				if !ok {
-					t.Fatalf("file %v was not read at all", filename)
-				}
-
-				if n != len(file.Content) {
-					t.Fatalf("file %v: read %v bytes, wanted %v bytes", filename, n, len(file.Content))
-				}
-				return nil
-			})
+			if test.modify == nil {
+				// check that no files were read this time
+				restictest.Equals(t, map[string]int{}, testFS.bytesRead)
+			}
+			restictest.Equals(t, test.statSecond.Files, summary.Files)
+			restictest.Equals(t, test.statSecond.Dirs, summary.Dirs)
+			restictest.Equals(t, test.statSecond.ProcessedBytes, summary.ProcessedBytes)
+			checkSnapshotStats(t, secondSnapshot, test.statSecond)
 
 			t.Logf("second backup saved as %v", secondSnapshotID.Str())
 			t.Logf("testfs: %v", testFS)
@@ -1815,7 +1904,7 @@ func TestArchiverErrorReporting(t *testing.T) {
 			arch := New(repo, fs.Track{FS: fs.Local{}}, Options{})
 			arch.Error = test.errFn
 
-			_, snapshotID, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
+			_, snapshotID, _, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
 			if test.mustError {
 				if err != nil {
 					t.Logf("found expected error (%v), skipping further checks", err)
@@ -1888,7 +1977,7 @@ func TestArchiverContextCanceled(t *testing.T) {
 
 	arch := New(repo, fs.Track{FS: fs.Local{}}, Options{})
 
-	_, snapshotID, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
+	_, snapshotID, _, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
 
 	if err != nil {
 		t.Logf("found expected error (%v)", err)
@@ -2027,7 +2116,7 @@ func TestArchiverAbortEarlyOnError(t *testing.T) {
 				SaveBlobConcurrency: 1,
 			})
 
-			_, _, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
+			_, _, _, err := arch.Snapshot(ctx, []string{"."}, SnapshotOptions{Time: time.Now()})
 			if !errors.Is(err, test.err) {
 				t.Errorf("expected error (%v) not found, got %v", test.err, err)
 			}
@@ -2055,7 +2144,7 @@ func snapshot(t testing.TB, repo restic.Repository, fs fs.FS, parent *restic.Sna
 		Time:           time.Now(),
 		ParentSnapshot: parent,
 	}
-	snapshot, _, err := arch.Snapshot(ctx, []string{filename}, sopts)
+	snapshot, _, _, err := arch.Snapshot(ctx, []string{filename}, sopts)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -2240,7 +2329,7 @@ func TestRacyFileSwap(t *testing.T) {
 	arch.runWorkers(ctx, wg)
 
 	// fs.Track will panic if the file was not closed
-	_, excluded, err := arch.Save(ctx, "/", tempfile, nil)
+	_, excluded, err := arch.save(ctx, "/", tempfile, nil)
 	if err == nil {
 		t.Errorf("Save() should have failed")
 	}

internal/archiver/testing.go

@@ -32,7 +32,7 @@ func TestSnapshot(t testing.TB, repo restic.Repository, path string, parent *res
 		}
 		opts.ParentSnapshot = sn
 	}
-	sn, _, err := arch.Snapshot(context.TODO(), []string{path}, opts)
+	sn, _, _, err := arch.Snapshot(context.TODO(), []string{path}, opts)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/archiver/testing_test.go

@@ -473,7 +473,7 @@ func TestTestEnsureSnapshot(t *testing.T) {
 				Hostname: "localhost",
 				Tags:     []string{"test"},
 			}
-			_, id, err := arch.Snapshot(ctx, []string{"."}, opts)
+			_, id, _, err := arch.Snapshot(ctx, []string{"."}, opts)
 			if err != nil {
 				t.Fatal(err)
 			}