restic/src/restic/migrations/s3_layout.go

package migrations

import (
	"context"
	"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 (m *S3Layout) moveFiles(ctx context.Context, be *s3.Backend, l backend.Layout, t restic.FileType) error {
	for name := range be.List(ctx, t) {
		h := restic.Handle{Type: t, Name: name}
		debug.Log("move %v", h)
		if err := be.Rename(h, l); err != nil {
			return err
		}
	}

	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.KeyFile,
		restic.SnapshotFile,
		restic.DataFile,
		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"
}