def start(self): """ Start elric master. Select all due jobs from jobstore and enqueue them into redis queue. Then update due jobs' information into jobstore. :return: """ if self.running: raise AlreadyRunningException self._stopped = False self.log.debug('eric master start...') while True: now = datetime.now(self.timezone) wait_seconds = None with self.jobstore_lock: for job_id, job_key, serialized_job in self.jobstore.get_due_jobs(now): # enqueue due job into redis queue self._enqueue_job(job_key, serialized_job) # update job's information, such as next_run_time job_in_dict = Job.deserialize_to_dict(serialized_job) last_run_time = Job.get_serial_run_times(job_in_dict, now) if last_run_time: next_run_time = Job.get_next_trigger_time(job_in_dict, last_run_time[-1]) if next_run_time: job_in_dict['next_run_time'] = next_run_time self.update_job(job_id, job_key, next_run_time, Job.dict_to_serialization(job_in_dict)) else: # if job has no next run time, then remove it from jobstore self.remove_job(job_id=job_id) # get next closet run time job from jobstore and set it to be wake up time closest_run_time = self.jobstore.get_closest_run_time() if closest_run_time is not None: wait_seconds = max(timedelta_seconds(closest_run_time - now), 0) self.log.debug('Next wakeup is due at %s (in %f seconds)' % (closest_run_time, wait_seconds)) self._event.wait(wait_seconds if wait_seconds is not None else self.MAX_WAIT_TIME) self._event.clear()