code: func (r *Client) GetDatasourceTypes() (map[string]DatasourceType, error) {
  	var (
  		raw     []byte
  		dsTypes = make(map[string]DatasourceType)
  		code    int
  		err     error
  	)
  	if raw, code, err = r.get("api/datasources/plugins", nil); err != nil {
  		return nil, err
  	}
  	if code != 200 {
  		return nil, fmt.Errorf("HTTP error %d: returns %s", code, raw)
  	}
  	err = json.Unmarshal(raw, &dsTypes)
  	return dsTypes, err
  }
docs: // GetDatasourceTypes gets all available plugins for the datasources.
  // It reflects GET /api/datasources/plugins API call.