engine.py 文件源码

def start(self):
        """Start the Engine greenlets.

        Returns:
             [Greenlet]: A list of Greenlets to be joined
        """
        if self._started:
            return []

        self._started = True

        self._leaser_loop = gevent.spawn(self.lease.acquire)
        self._runner_loop = gevent.spawn(self._run)
        self._machine_loop = gevent.spawn(self._machine_heartbeat)

        return [self._machine_loop, self._runner_loop, self._leaser_loop]