func (ta *TabletActor) updateReplicationGraphForPromotedSlave(tablet *topo.TabletInfo, actionNode *ActionNode) error {
// Remove tablet from the replication graph if this is not already the master.
if tablet.Parent.Uid != topo.NO_TABLET {
err := ta.ts.DeleteReplicationPath(tablet.Keyspace, tablet.Shard, tablet.ReplicationPath())
if err != nil && err != topo.ErrNoNode {
return err
}
}
// Update tablet regardless - trend towards consistency.
tablet.State = topo.STATE_READ_WRITE
tablet.Type = topo.TYPE_MASTER
tablet.Parent.Cell = ""
tablet.Parent.Uid = topo.NO_TABLET
err := topo.UpdateTablet(ta.ts, tablet)
if err != nil {
return err
}
// NOTE(msolomon) A serving graph update is required, but in order for the
// shard to be consistent the master must be scrapped first. That is
// externally coordinated by the wrangler reparent action.
// Insert the new tablet location in the replication graph now that
// we've updated the tablet.
err = ta.ts.CreateReplicationPath(tablet.Keyspace, tablet.Shard, tablet.ReplicationPath())
if err != nil && err != topo.ErrNodeExists {
return err
}
return nil
}