code: func (s *Store) NodeService(nodeName string, serviceID string) (uint64, *structs.NodeService, error) {
  	tx := s.db.Txn(false)
  	defer tx.Abort()
  
  	// Get the table index.
  	idx := maxIndexTxn(tx, "services")
  
  	// Query the service
  	service, err := s.getNodeServiceTxn(tx, nodeName, serviceID)
  	if err != nil {
  		return 0, nil, fmt.Errorf("failed querying service for node %q: %s", nodeName, err)
  	}
  
  	return idx, service, nil
  }
docs: // NodeService is used to retrieve a specific service associated with the given
  // node.