// ReparentShard creates the reparenting action and launches a goroutine
// to coordinate the procedure.
//
//
// leaveMasterReadOnly: leave the master in read-only mode, even
// though all the other necessary updates have been made.
// forceReparentToCurrentMaster: mostly for test setups, this can
// cause data loss.
func (wr *Wrangler) ReparentShard(keyspace, shard string, masterElectTabletAlias topo.TabletAlias, leaveMasterReadOnly, forceReparentToCurrentMaster bool) error {
// lock the shard
actionNode := actionnode.ReparentShard(masterElectTabletAlias)
lockPath, err := wr.lockShard(keyspace, shard, actionNode)
if err != nil {
return err
}
// do the work
err = wr.reparentShardLocked(keyspace, shard, masterElectTabletAlias, leaveMasterReadOnly, forceReparentToCurrentMaster)
// and unlock
return wr.unlockShard(keyspace, shard, actionNode, lockPath, err)
}
// EmergencyReparentShard will make the provided tablet the master for
// the shard, when the old master is completely unreachable.
func (wr *Wrangler) EmergencyReparentShard(ctx context.Context, keyspace, shard string, masterElectTabletAlias *pb.TabletAlias, waitSlaveTimeout time.Duration) error {
// lock the shard
actionNode := actionnode.ReparentShard(emergencyReparentShardOperation, masterElectTabletAlias)
lockPath, err := wr.lockShard(ctx, keyspace, shard, actionNode)
if err != nil {
return err
}
// Create reusable Reparent event with available info
ev := &events.Reparent{}
// do the work
err = wr.emergencyReparentShardLocked(ctx, ev, keyspace, shard, masterElectTabletAlias, waitSlaveTimeout)
if err != nil {
event.DispatchUpdate(ev, "failed EmergencyReparentShard: "+err.Error())
} else {
event.DispatchUpdate(ev, "finished EmergencyReparentShard")
}
// and unlock
return wr.unlockShard(ctx, keyspace, shard, actionNode, lockPath, err)
}