// Restore is the main entry point for backup restore. If there is no
// appropriate backup on the BackupStorage, Restore logs an error
// and returns ErrNoBackup. Any other error is returned.
func Restore(
ctx context.Context,
mysqld MysqlDaemon,
dir string,
restoreConcurrency int,
hookExtraEnv map[string]string,
localMetadata map[string]string,
logger logutil.Logger,
deleteBeforeRestore bool) (replication.Position, error) {
// find the right backup handle: most recent one, with a MANIFEST
logger.Infof("Restore: looking for a suitable backup to restore")
bs, err := backupstorage.GetBackupStorage()
if err != nil {
return replication.Position{}, err
}
defer bs.Close()
bhs, err := bs.ListBackups(dir)
if err != nil {
return replication.Position{}, fmt.Errorf("ListBackups failed: %v", err)
}
var bh backupstorage.BackupHandle
var bm BackupManifest
var toRestore int
for toRestore = len(bhs) - 1; toRestore >= 0; toRestore-- {
bh = bhs[toRestore]
rc, err := bh.ReadFile(backupManifest)
if err != nil {
log.Warningf("Possibly incomplete backup %v in directory %v on BackupStorage: can't read MANIFEST: %v)", bh.Name(), dir, err)
continue
}
err = json.NewDecoder(rc).Decode(&bm)
rc.Close()
if err != nil {
log.Warningf("Possibly incomplete backup %v in directory %v on BackupStorage (cannot JSON decode MANIFEST: %v)", bh.Name(), dir, err)
continue
}
logger.Infof("Restore: found backup %v %v to restore with %v files", bh.Directory(), bh.Name(), len(bm.FileEntries))
break
}
if toRestore < 0 {
logger.Errorf("No backup to restore on BackupStorage for directory %v. Starting up empty.", dir)
if err = populateLocalMetadata(mysqld, localMetadata); err == nil {
err = ErrNoBackup
}
return replication.Position{}, err
}
if !deleteBeforeRestore {
logger.Infof("Restore: checking no existing data is present")
ok, err := checkNoDB(ctx, mysqld)
if err != nil {
return replication.Position{}, err
}
if !ok {
logger.Infof("Auto-restore is enabled, but mysqld already contains data. Assuming vttablet was just restarted.")
if err = populateLocalMetadata(mysqld, localMetadata); err == nil {
err = ErrExistingDB
}
return replication.Position{}, err
}
}
logger.Infof("Restore: shutdown mysqld")
err = mysqld.Shutdown(ctx, true)
if err != nil {
return replication.Position{}, err
}
logger.Infof("Restore: deleting existing files")
if err := removeExistingFiles(mysqld.Cnf()); err != nil {
return replication.Position{}, err
}
logger.Infof("Restore: reinit config file")
err = mysqld.ReinitConfig(ctx)
if err != nil {
return replication.Position{}, err
}
logger.Infof("Restore: copying all files")
if err := restoreFiles(mysqld.Cnf(), bh, bm.FileEntries, restoreConcurrency); err != nil {
return replication.Position{}, err
}
// mysqld needs to be running in order for mysql_upgrade to work.
// If we've just restored from a backup from previous MySQL version then mysqld
// may fail to start due to a different structure of mysql.* tables. The flag
// --skip-grant-tables ensures that these tables are not read until mysql_upgrade
// is executed. And since with --skip-grant-tables anyone can connect to MySQL
// without password, we are passing --skip-networking to greatly reduce the set
// of those who can connect.
logger.Infof("Restore: starting mysqld for mysql_upgrade")
err = mysqld.Start(ctx, "--skip-grant-tables", "--skip-networking")
if err != nil {
return replication.Position{}, err
}
logger.Infof("Restore: running mysql_upgrade")
if err := mysqld.RunMysqlUpgrade(); err != nil {
return replication.Position{}, fmt.Errorf("mysql_upgrade failed: %v", err)
}
// Populate local_metadata before starting without --skip-networking,
// so it's there before we start announcing ourselves.
logger.Infof("Restore: populating local_metadata")
err = populateLocalMetadata(mysqld, localMetadata)
if err != nil {
return replication.Position{}, err
}
// The MySQL manual recommends restarting mysqld after running mysql_upgrade,
// so that any changes made to system tables take effect.
logger.Infof("Restore: restarting mysqld after mysql_upgrade")
err = mysqld.Shutdown(ctx, true)
if err != nil {
return replication.Position{}, err
}
err = mysqld.Start(ctx)
if err != nil {
return replication.Position{}, err
}
return bm.Position, nil
}
// Restore is the main entry point for backup restore. If there is no
// appropriate backup on the BackupStorage, Restore logs an error
// and returns ErrNoBackup. Any other error is returned.
func Restore(ctx context.Context, mysqld MysqlDaemon, dir string, restoreConcurrency int, hookExtraEnv map[string]string) (replication.Position, error) {
// find the right backup handle: most recent one, with a MANIFEST
log.Infof("Restore: looking for a suitable backup to restore")
bs, err := backupstorage.GetBackupStorage()
if err != nil {
return replication.Position{}, err
}
defer bs.Close()
bhs, err := bs.ListBackups(dir)
if err != nil {
return replication.Position{}, fmt.Errorf("ListBackups failed: %v", err)
}
var bh backupstorage.BackupHandle
var bm BackupManifest
var toRestore int
for toRestore = len(bhs) - 1; toRestore >= 0; toRestore-- {
bh = bhs[toRestore]
rc, err := bh.ReadFile(backupManifest)
if err != nil {
log.Warningf("Possibly incomplete backup %v in directory %v on BackupStorage: can't read MANIFEST: %v)", bh.Name(), dir, err)
continue
}
err = json.NewDecoder(rc).Decode(&bm)
rc.Close()
if err != nil {
log.Warningf("Possibly incomplete backup %v in directory %v on BackupStorage (cannot JSON decode MANIFEST: %v)", bh.Name(), dir, err)
continue
}
log.Infof("Restore: found backup %v %v to restore with %v files", bh.Directory(), bh.Name(), len(bm.FileEntries))
break
}
if toRestore < 0 {
log.Errorf("No backup to restore on BackupStorage for directory %v", dir)
return replication.Position{}, ErrNoBackup
}
log.Infof("Restore: checking no existing data is present")
ok, err := checkNoDB(ctx, mysqld)
if err != nil {
return replication.Position{}, err
}
if !ok {
return replication.Position{}, ErrExistingDB
}
log.Infof("Restore: shutdown mysqld")
err = mysqld.Shutdown(ctx, true)
if err != nil {
return replication.Position{}, err
}
log.Infof("Restore: deleting existing files")
if err := removeExistingFiles(mysqld.Cnf()); err != nil {
return replication.Position{}, err
}
log.Infof("Restore: copying all files")
if err := restoreFiles(mysqld.Cnf(), bh, bm.FileEntries, restoreConcurrency); err != nil {
return replication.Position{}, err
}
// mysqld needs to be running in order for mysql_upgrade to work.
log.Infof("Restore: starting mysqld for mysql_upgrade")
err = mysqld.Start(ctx)
if err != nil {
return replication.Position{}, err
}
log.Infof("Restore: running mysql_upgrade")
if err := mysqld.RunMysqlUpgrade(); err != nil {
return replication.Position{}, fmt.Errorf("mysql_upgrade failed: %v", err)
}
// The MySQL manual recommends restarting mysqld after running mysql_upgrade,
// so that any changes made to system tables take effect.
log.Infof("Restore: restarting mysqld after mysql_upgrade")
err = mysqld.Shutdown(ctx, true)
if err != nil {
return replication.Position{}, err
}
err = mysqld.Start(ctx)
if err != nil {
return replication.Position{}, err
}
return bm.Position, nil
}