def create_external_store(self, project_name, config):
        """ create log store 
        Unsuccessful opertaion will cause an LogException.

        :type project_name: string
        :param project_name: the Project name 

        :type config : ExternalStoreConfig
        :param config :external store config


        :return: CreateExternalStoreResponse
        
        :raise: LogException
        """
        params = {}
        resource = "/externalstores"
        headers = {"x-log-bodyrawsize": '0', "Content-Type": "application/json"}

        body_str = six.b(json.dumps(config.to_json()))

        (resp, header) = self._send("POST", project_name, body_str, resource, params, headers)
        return CreateExternalStoreResponse(header, resp)
create log store 
        Unsuccessful opertaion will cause an LogException.

        :type project_name: string
        :param project_name: the Project name 

        :type config : ExternalStoreConfig
        :param config :external store config


        :return: CreateExternalStoreResponse
        
        :raise: LogException