code: func (s *IndicesRolloverService) buildURL() (string, url.Values, error) {
  	// Build URL
  	var err error
  	var path string
  	if s.newIndex != "" {
  		path, err = uritemplates.Expand("/{alias}/_rollover/{new_index}", map[string]string{
  			"alias":     s.alias,
  			"new_index": s.newIndex,
  		})
  	} else {
  		path, err = uritemplates.Expand("/{alias}/_rollover", map[string]string{
  			"alias": s.alias,
  		})
  	}
  	if err != nil {
  		return "", url.Values{}, err
  	}
  
  	// Add query string parameters
  	params := url.Values{}
  	if s.pretty {
  		params.Set("pretty", "true")
  	}
  	if s.dryRun {
  		params.Set("dry_run", "true")
  	}
  	if s.masterTimeout != "" {
  		params.Set("master_timeout", s.masterTimeout)
  	}
  	if s.timeout != "" {
  		params.Set("timeout", s.timeout)
  	}
  	if s.waitForActiveShards != "" {
  		params.Set("wait_for_active_shards", s.waitForActiveShards)
  	}
  	return path, params, nil
  }
docs: // buildURL builds the URL for the operation.