Moves files

internal/migrations/doc.go

@@ -0,0 +1,2 @@
+// Package migrations contains migrations that can be applied to a repository and/or backend.
+package migrations

internal/migrations/interface.go

@@ -0,0 +1,21 @@
+package migrations
+
+import (
+	"context"
+	"restic"
+)
+
+// Migration implements a data migration.
+type Migration interface {
+	// Check returns true if the migration can be applied to a repo.
+	Check(context.Context, restic.Repository) (bool, error)
+
+	// Apply runs the migration.
+	Apply(context.Context, restic.Repository) error
+
+	// Name returns a short name.
+	Name() string
+
+	// Descr returns a description what the migration does.
+	Desc() string
+}

internal/migrations/list.go

@@ -0,0 +1,8 @@
+package migrations
+
+// All contains all migrations.
+var All []Migration
+
+func register(m Migration) {
+	All = append(All, m)
+}

internal/migrations/s3_layout.go

@@ -0,0 +1,118 @@
+package migrations
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path"
+	"restic"
+	"restic/backend"
+	"restic/backend/s3"
+	"restic/debug"
+	"restic/errors"
+)
+
+func init() {
+	register(&S3Layout{})
+}
+
+// S3Layout migrates a repository on an S3 backend from the "s3legacy" to the
+// "default" layout.
+type S3Layout struct{}
+
+// Check tests whether the migration can be applied.
+func (m *S3Layout) Check(ctx context.Context, repo restic.Repository) (bool, error) {
+	be, ok := repo.Backend().(*s3.Backend)
+	if !ok {
+		debug.Log("backend is not s3")
+		return false, nil
+	}
+
+	if be.Layout.Name() != "s3legacy" {
+		debug.Log("layout is not s3legacy")
+		return false, nil
+	}
+
+	return true, nil
+}
+
+func retry(max int, fail func(err error), f func() error) error {
+	var err error
+	for i := 0; i < max; i++ {
+		err = f()
+		if err == nil {
+			return err
+		}
+		if fail != nil {
+			fail(err)
+		}
+	}
+	return err
+}
+
+// maxErrors for retrying renames on s3.
+const maxErrors = 20
+
+func (m *S3Layout) moveFiles(ctx context.Context, be *s3.Backend, l backend.Layout, t restic.FileType) error {
+	printErr := func(err error) {
+		fmt.Fprintf(os.Stderr, "renaming file returned error: %v\n", err)
+	}
+
+	for name := range be.List(ctx, t) {
+		h := restic.Handle{Type: t, Name: name}
+		debug.Log("move %v", h)
+
+		retry(maxErrors, printErr, func() error {
+			return be.Rename(h, l)
+		})
+	}
+
+	return nil
+}
+
+// Apply runs the migration.
+func (m *S3Layout) Apply(ctx context.Context, repo restic.Repository) error {
+	be, ok := repo.Backend().(*s3.Backend)
+	if !ok {
+		debug.Log("backend is not s3")
+		return errors.New("backend is not s3")
+	}
+
+	oldLayout := &backend.S3LegacyLayout{
+		Path: be.Path(),
+		Join: path.Join,
+	}
+
+	newLayout := &backend.DefaultLayout{
+		Path: be.Path(),
+		Join: path.Join,
+	}
+
+	be.Layout = oldLayout
+
+	for _, t := range []restic.FileType{
+		restic.SnapshotFile,
+		restic.DataFile,
+		restic.KeyFile,
+		restic.LockFile,
+	} {
+		err := m.moveFiles(ctx, be, newLayout, t)
+		if err != nil {
+			return err
+		}
+	}
+
+	be.Layout = newLayout
+
+	return nil
+}
+
+// Name returns the name for this migration.
+func (m *S3Layout) Name() string {
+	return "s3_layout"
+}
+
+// Desc returns a short description what the migration does.
+func (m *S3Layout) Desc() string {
+	return "move files from 's3legacy' to the 'default' repository layout"
+}