repository: replace StartPackUploader+Flush with WithBlobUploader

The new method combines both step into a single wrapper function. Thus
it ensures that both are always called in pairs. As an additional
benefit this slightly reduces the boilerplate to upload blobs.

cmd/restic/cmd_debug.go

@@ -352,13 +352,7 @@ func loadBlobs(ctx context.Context, opts DebugExamineOptions, repo restic.Reposi
 		return err
 	}
 
-	wg, ctx := errgroup.WithContext(ctx)
-
-	if opts.ReuploadBlobs {
-		repo.StartPackUploader(ctx, wg)
-	}
-
-	wg.Go(func() error {
+	err = repo.WithBlobUploader(ctx, func(ctx context.Context) error {
 		for _, blob := range list {
 			printer.S("      loading blob %v at %v (length %v)", blob.ID, blob.Offset, blob.Length)
 			if int(blob.Offset+blob.Length) > len(pack) {
@@ -423,14 +417,9 @@ func loadBlobs(ctx context.Context, opts DebugExamineOptions, repo restic.Reposi
 				printer.S("         uploaded %v %v", blob.Type, id)
 			}
 		}
-
-		if opts.ReuploadBlobs {
-			return repo.Flush(ctx)
-		}
 		return nil
 	})
-
-	return wg.Wait()
+	return err
 }
 
 func storePlainBlob(id restic.ID, prefix string, plain []byte, printer progress.Printer) error {

cmd/restic/cmd_recover.go

@@ -12,7 +12,6 @@ import (
 	"github.com/restic/restic/internal/ui"
 	"github.com/restic/restic/internal/ui/progress"
 	"github.com/spf13/cobra"
-	"golang.org/x/sync/errgroup"
 )
 
 func newRecoverCommand(globalOptions *GlobalOptions) *cobra.Command {
@@ -152,24 +151,15 @@ func runRecover(ctx context.Context, gopts GlobalOptions, term ui.Terminal) erro
 		}
 	}
 
-	wg, wgCtx := errgroup.WithContext(ctx)
-	repo.StartPackUploader(wgCtx, wg)
-
 	var treeID restic.ID
-	wg.Go(func() error {
+	err = repo.WithBlobUploader(ctx, func(ctx context.Context) error {
 		var err error
-		treeID, err = data.SaveTree(wgCtx, repo, tree)
+		treeID, err = data.SaveTree(ctx, repo, tree)
 		if err != nil {
 			return errors.Fatalf("unable to save new tree to the repository: %v", err)
 		}
-
-		err = repo.Flush(wgCtx)
-		if err != nil {
-			return errors.Fatalf("unable to save blobs to the repository: %v", err)
-		}
 		return nil
 	})
-	err = wg.Wait()
 	if err != nil {
 		return err
 	}

cmd/restic/cmd_rewrite.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
-	"golang.org/x/sync/errgroup"
 
 	"github.com/restic/restic/internal/data"
 	"github.com/restic/restic/internal/debug"
@@ -192,21 +191,13 @@ func rewriteSnapshot(ctx context.Context, repo *repository.Repository, sn *data.
 func filterAndReplaceSnapshot(ctx context.Context, repo restic.Repository, sn *data.Snapshot,
 	filter rewriteFilterFunc, dryRun bool, forget bool, newMetadata *snapshotMetadata, addTag string, printer progress.Printer) (bool, error) {
 
-	wg, wgCtx := errgroup.WithContext(ctx)
-	repo.StartPackUploader(wgCtx, wg)
-
 	var filteredTree restic.ID
 	var summary *data.SnapshotSummary
-	wg.Go(func() error {
+	err := repo.WithBlobUploader(ctx, func(ctx context.Context) error {
 		var err error
 		filteredTree, summary, err = filter(ctx, sn)
-		if err != nil {
-			return err
-		}
-
-		return repo.Flush(wgCtx)
+		return err
 	})
-	err := wg.Wait()
 	if err != nil {
 		return false, err
 	}