tabletmanager: Record local metadata values before changing tablet. (#2070)

The prior addition of a call to refreshTablet() before generating local
metadata values caused the values to change, since the tablet type has
been temporarily changed to RESTORE.

go/vt/tabletmanager/restore.go

@@ -37,6 +37,12 @@ func (agent *ActionAgent) RestoreData(ctx context.Context, logger logutil.Logger
 }
 
 func (agent *ActionAgent) restoreDataLocked(ctx context.Context, logger logutil.Logger, deleteBeforeRestore bool) error {
+	// Record local metadata values before we start changing the tablet record.
+	localMetadata, err := agent.getLocalMetadataValues()
+	if err != nil {
+		return err
+	}
+
 	// change type to RESTORE (using UpdateTabletFields so it's
 	// always authorized)
 	tablet := agent.Tablet()
@@ -57,10 +63,6 @@ func (agent *ActionAgent) restoreDataLocked(ctx context.Context, logger logutil.
 	// If we're not ok, return an error and the agent will log.Fatalf,
 	// causing the process to be restarted and the restore retried.
 	dir := fmt.Sprintf("%v/%v", tablet.Keyspace, tablet.Shard)
-	localMetadata, err := agent.getLocalMetadataValues()
-	if err != nil {
-		return err
-	}
 	pos, err := mysqlctl.Restore(ctx, agent.MysqlDaemon, dir, *restoreConcurrency, agent.hookExtraEnv(), localMetadata, logger, deleteBeforeRestore)
 	switch err {
 	case nil:

test/backup.py

@@ -187,6 +187,16 @@ class TestBackup(unittest.TestCase):
     # check the new slave has the data
     self._check_data(tablet_replica2, 2, 'replica2 tablet getting data')
 
+    # check that the restored slave has the right local_metadata
+    result = tablet_replica2.mquery('_vt', 'select * from local_metadata')
+    metadata = {}
+    for row in result:
+      metadata[row[0]] = row[1]
+    self.assertEqual(metadata['Alias'], 'test_nj-0000062346')
+    self.assertEqual(metadata['ClusterAlias'], 'test_keyspace.0')
+    self.assertEqual(metadata['DataCenter'], 'test_nj')
+    self.assertEqual(metadata['PromotionRule'], 'neutral')
+
     # check that the backup shows up in the listing
     backups = self._list_backups()
     logging.debug('list of backups: %s', backups)