def run_once(self):
        '''comsume queues and feed tasks to fetcher, once'''

        self._update_projects()
        self._check_task_done()
        self._check_request()
        while self._check_cronjob():
            pass
        self._check_select()
        self._check_delete()
        self._try_dump_cnt()
comsume queues and feed tasks to fetcher, once
pyspider/scheduler/scheduler.py