code: func (s *Store) EnsureNode(idx uint64, node *structs.Node) error {
  	tx := s.db.Txn(true)
  	defer tx.Abort()
  
  	// Call the node upsert
  	if err := s.ensureNodeTxn(tx, idx, node); err != nil {
  		return err
  	}
  
  	tx.Commit()
  	return nil
  }
docs: // EnsureNode is used to upsert node registration or modification.