Log changed files after backup

internal/service/service.go

@@ -586,6 +586,11 @@ func (s *Service) executeBackup(ctx context.Context, run model.Run) (result mode
 			result.Status, result.ErrorCode, result.Message = "warning", "connectivity", result.Message+"; repository unmount failed: "+err.Error()
 		}
 	}()
+	previousSnapshot, previousSnapshotOK, previousSnapshotErr := s.latestJobSnapshot(ctx, mounted.Repository, job.ID)
+	if previousSnapshotErr != nil {
+		appendLiveLog(&live, "Änderungsliste: vorheriger Snapshot konnte nicht ermittelt werden: "+previousSnapshotErr.Error())
+		s.updateActive(live)
+	}
 	prepared, err := s.workloads.Prepare(ctx, job)
 	if err != nil {
 		return failedError(run, err)
@@ -671,6 +676,10 @@ func (s *Service) executeBackup(ctx context.Context, run model.Run) (result mode
 		failedRun.LiveLog = live.LiveLog
 		return failedRun
 	}
+	if previousSnapshotOK && summary.SnapshotID != "" {
+		s.appendBackupDiffLog(ctx, &live, mounted.Repository, previousSnapshot, summary.SnapshotID)
+		s.updateActive(live)
+	}
 	appendLiveLog(&live, "Backup-Daten übertragen; Aufbewahrung wird angewendet")
 	s.updateActive(live)
 	if err := s.restic.Forget(ctx, mounted.Repository, job); err != nil {
@@ -692,6 +701,69 @@ func (s *Service) executeBackup(ctx context.Context, run model.Run) (result mode
 	return run
 }
 
+func (s *Service) latestJobSnapshot(ctx context.Context, repo model.Repository, jobID string) (model.Snapshot, bool, error) {
+	snapshots, err := s.restic.Snapshots(ctx, repo)
+	if err != nil {
+		return model.Snapshot{}, false, err
+	}
+	tag := "job:" + jobID
+	var latest model.Snapshot
+	found := false
+	for _, snapshot := range snapshots {
+		if !hasTag(snapshot.Tags, tag) || hasTag(snapshot.Tags, "usb-image") {
+			continue
+		}
+		if !found || snapshot.Time.After(latest.Time) {
+			latest = snapshot
+			found = true
+		}
+	}
+	return latest, found, nil
+}
+
+func hasTag(tags []string, wanted string) bool {
+	for _, tag := range tags {
+		if tag == wanted {
+			return true
+		}
+	}
+	return false
+}
+
+func (s *Service) appendBackupDiffLog(ctx context.Context, run *model.Run, repo model.Repository, previous model.Snapshot, currentSnapshotID string) {
+	const limit = 50
+	diff, err := s.restic.Diff(ctx, repo, previous.ID, currentSnapshotID, limit)
+	if err != nil {
+		appendLiveLog(run, "Änderungsliste konnte nicht erstellt werden: "+err.Error())
+		return
+	}
+	if diff.Total == 0 {
+		appendLiveLog(run, "Änderungsliste gegenüber "+shortID(previous.ID)+": keine geänderten Pfade erkannt")
+		return
+	}
+	if diff.Total > len(diff.Entries) {
+		appendLiveLog(run, fmt.Sprintf("Änderungsliste gegenüber %s: letzte %d von %d geänderten Pfaden", shortID(previous.ID), len(diff.Entries), diff.Total))
+	} else {
+		appendLiveLog(run, fmt.Sprintf("Änderungsliste gegenüber %s: %d geänderte Pfade", shortID(previous.ID), diff.Total))
+	}
+	for _, entry := range diff.Entries {
+		appendLiveLog(run, fmt.Sprintf("%s %s", diffKindLabel(entry.Kind), entry.Path))
+	}
+}
+
+func diffKindLabel(kind string) string {
+	switch kind {
+	case "new":
+		return "NEU"
+	case "removed":
+		return "GELÖSCHT"
+	case "modified":
+		return "GEÄNDERT"
+	default:
+		return strings.ToUpper(kind)
+	}
+}
+
 func (s *Service) updateActive(run model.Run) {
 	s.queue.UpdateActive(run.ID, func(active *model.Run) {
 		active.ProgressPercent, active.ProgressBytes, active.ProgressTotal = run.ProgressPercent, run.ProgressBytes, run.ProgressTotal