backup: hide files from status which are read completely but not saved

As the FileSaver is asynchronously waiting for all blobs of a file to be
stored, the number of active files is higher than the number of files
from which restic is reading concurrently. Thus to not confuse users,
only display files in the status from which restic is currently reading.

internal/archiver/archiver.go

@@ -68,6 +68,9 @@ type Archiver struct {
 	// be in the snapshot after saving. s contains some statistics about this
 	// particular file/dir.
 	//
+	// Once reading a file has completed successfully (but not saving it yet),
+	// CompleteItem will be called with current == nil.
+	//
 	// CompleteItem may be called asynchronously from several different
 	// goroutines!
 	CompleteItem func(item string, previous, current *restic.Node, s ItemStats, d time.Duration)
@@ -431,6 +434,8 @@ func (arch *Archiver) Save(ctx context.Context, snPath, target string, previous
 		// Save will close the file, we don't need to do that
 		fn = arch.fileSaver.Save(ctx, snPath, target, file, fi, func() {
 			arch.StartFile(snPath)
+		}, func() {
+			arch.CompleteItem(snPath, nil, nil, ItemStats{}, 0)
 		}, func(node *restic.Node, stats ItemStats) {
 			arch.CompleteItem(snPath, previous, node, stats, time.Since(start))
 		})

internal/archiver/archiver_test.go

@@ -53,6 +53,8 @@ func saveFile(t testing.TB, repo restic.Repository, filename string, filesystem
 	}
 
 	var (
+		completeReadingCallback bool
+
 		completeCallbackNode  *restic.Node
 		completeCallbackStats ItemStats
 		completeCallback      bool
@@ -60,6 +62,13 @@ func saveFile(t testing.TB, repo restic.Repository, filename string, filesystem
 		startCallback bool
 	)
 
+	completeReading := func() {
+		completeReadingCallback = true
+		if completeCallback {
+			t.Error("callbacks called in wrong order")
+		}
+	}
+
 	complete := func(node *restic.Node, stats ItemStats) {
 		completeCallback = true
 		completeCallbackNode = node
@@ -80,7 +89,7 @@ func saveFile(t testing.TB, repo restic.Repository, filename string, filesystem
 		t.Fatal(err)
 	}
 
-	res := arch.fileSaver.Save(ctx, "/", filename, file, fi, start, complete)
+	res := arch.fileSaver.Save(ctx, "/", filename, file, fi, start, completeReading, complete)
 
 	fnr := res.take(ctx)
 	if fnr.err != nil {
@@ -101,6 +110,10 @@ func saveFile(t testing.TB, repo restic.Repository, filename string, filesystem
 		t.Errorf("start callback did not happen")
 	}
 
+	if !completeReadingCallback {
+		t.Errorf("completeReading callback did not happen")
+	}
+
 	if !completeCallback {
 		t.Errorf("complete callback did not happen")
 	}

internal/archiver/file_saver.go

@@ -67,17 +67,21 @@ func (s *FileSaver) TriggerShutdown() {
 type CompleteFunc func(*restic.Node, ItemStats)
 
 // Save stores the file f and returns the data once it has been completed. The
-// file is closed by Save.
+// file is closed by Save. completeReading is only called if the file was read
-func (s *FileSaver) Save(ctx context.Context, snPath string, target string, file fs.File, fi os.FileInfo, start func(), complete CompleteFunc) FutureNode {
+// successfully. complete is always called. If completeReading is called, then
+// this will always happen before calling complete.
+func (s *FileSaver) Save(ctx context.Context, snPath string, target string, file fs.File, fi os.FileInfo, start func(), completeReading func(), complete CompleteFunc) FutureNode {
 	fn, ch := newFutureNode()
 	job := saveFileJob{
 		snPath: snPath,
 		target: target,
 		file:   file,
 		fi:     fi,
-		start:    start,
-		complete: complete,
 		ch:     ch,
+
+		start:           start,
+		completeReading: completeReading,
+		complete:        complete,
 	}
 
 	select {
@@ -97,12 +101,14 @@ type saveFileJob struct {
 	file   fs.File
 	fi     os.FileInfo
 	ch     chan<- futureNodeResult
-	complete CompleteFunc
+
 	start           func()
+	completeReading func()
+	complete        CompleteFunc
 }
 
 // saveFile stores the file f in the repo, then closes it.
-func (s *FileSaver) saveFile(ctx context.Context, chnker *chunker.Chunker, snPath string, target string, f fs.File, fi os.FileInfo, start func(), finish func(res futureNodeResult)) {
+func (s *FileSaver) saveFile(ctx context.Context, chnker *chunker.Chunker, snPath string, target string, f fs.File, fi os.FileInfo, start func(), finishReading func(), finish func(res futureNodeResult)) {
 	start()
 
 	fnr := futureNodeResult{
@@ -227,6 +233,7 @@ func (s *FileSaver) saveFile(ctx context.Context, chnker *chunker.Chunker, snPat
 	// after reaching the end of this method
 	remaining += idx + 1
 	lock.Unlock()
+	finishReading()
 	completeBlob()
 }
 
@@ -246,7 +253,11 @@ func (s *FileSaver) worker(ctx context.Context, jobs <-chan saveFileJob) {
 			}
 		}
 
-		s.saveFile(ctx, chnker, job.snPath, job.target, job.file, job.fi, job.start, func(res futureNodeResult) {
+		s.saveFile(ctx, chnker, job.snPath, job.target, job.file, job.fi, job.start, func() {
+			if job.completeReading != nil {
+				job.completeReading()
+			}
+		}, func(res futureNodeResult) {
 			if job.complete != nil {
 				job.complete(res.node, res.stats)
 			}

internal/archiver/file_saver_test.go

@@ -60,6 +60,7 @@ func TestFileSaver(t *testing.T) {
 	defer cleanup()
 
 	startFn := func() {}
+	completeReadingFn := func() {}
 	completeFn := func(*restic.Node, ItemStats) {}
 
 	testFs := fs.Local{}
@@ -78,7 +79,7 @@ func TestFileSaver(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		ff := s.Save(ctx, filename, filename, f, fi, startFn, completeFn)
+		ff := s.Save(ctx, filename, filename, f, fi, startFn, completeReadingFn, completeFn)
 		results = append(results, ff)
 	}