restic/internal/migrations/upgrade_repo_v2.go

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package migrations
import (
"context"
"fmt"
"io"
"os"
"path/filepath"
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"github.com/restic/restic/internal/restic"
)
func init() {
register(&UpgradeRepoV2{})
}
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type UpgradeRepoV2Error struct {
UploadNewConfigError error
ReuploadOldConfigError error
BackupFilePath string
}
func (err *UpgradeRepoV2Error) Error() string {
if err.ReuploadOldConfigError != nil {
return fmt.Sprintf("error uploading config (%v), re-uploading old config filed failed as well (%v), but there is a backup of the config file in %v", err.UploadNewConfigError, err.ReuploadOldConfigError, err.BackupFilePath)
}
return fmt.Sprintf("error uploading config (%v), re-uploaded old config was successful, there is a backup of the config file in %v", err.UploadNewConfigError, err.BackupFilePath)
}
func (err *UpgradeRepoV2Error) Unwrap() error {
// consider the original upload error as the primary cause
return err.UploadNewConfigError
}
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type UpgradeRepoV2 struct{}
func (*UpgradeRepoV2) Name() string {
return "upgrade_repo_v2"
}
func (*UpgradeRepoV2) Desc() string {
return "upgrade a repository to version 2"
}
func (*UpgradeRepoV2) Check(_ context.Context, repo restic.Repository) (bool, string, error) {
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isV1 := repo.Config().Version == 1
reason := ""
if !isV1 {
reason = fmt.Sprintf("repository is already upgraded to version %v", repo.Config().Version)
}
return isV1, reason, nil
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}
func (*UpgradeRepoV2) RepoCheck() bool {
return true
}
func (*UpgradeRepoV2) upgrade(ctx context.Context, repo restic.Repository) error {
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h := restic.Handle{Type: restic.ConfigFile}
if !repo.Backend().HasAtomicReplace() {
// remove the original file for backends which do not support atomic overwriting
err := repo.Backend().Remove(ctx, h)
if err != nil {
return fmt.Errorf("remove config failed: %w", err)
}
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}
// upgrade config
cfg := repo.Config()
cfg.Version = 2
err := restic.SaveConfig(ctx, repo, cfg)
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if err != nil {
return fmt.Errorf("save new config file failed: %w", err)
}
return nil
}
func (m *UpgradeRepoV2) Apply(ctx context.Context, repo restic.Repository) error {
tempdir, err := os.MkdirTemp("", "restic-migrate-upgrade-repo-v2-")
if err != nil {
return fmt.Errorf("create temp dir failed: %w", err)
}
h := restic.Handle{Type: restic.ConfigFile}
// read raw config file and save it to a temp dir, just in case
var rawConfigFile []byte
err = repo.Backend().Load(ctx, h, 0, 0, func(rd io.Reader) (err error) {
rawConfigFile, err = io.ReadAll(rd)
return err
})
if err != nil {
return fmt.Errorf("load config file failed: %w", err)
}
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backupFileName := filepath.Join(tempdir, "config")
err = os.WriteFile(backupFileName, rawConfigFile, 0600)
if err != nil {
return fmt.Errorf("write config file backup to %v failed: %w", tempdir, err)
}
// run the upgrade
err = m.upgrade(ctx, repo)
if err != nil {
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// build an error we can return to the caller
repoError := &UpgradeRepoV2Error{
UploadNewConfigError: err,
BackupFilePath: backupFileName,
}
// try contingency methods, reupload the original file
_ = repo.Backend().Remove(ctx, h)
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err = repo.Backend().Save(ctx, h, restic.NewByteReader(rawConfigFile, nil))
if err != nil {
repoError.ReuploadOldConfigError = err
}
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return repoError
}
_ = os.Remove(backupFileName)
_ = os.Remove(tempdir)
return nil
}