Question

我之前曾问过how to run several autobahn.ApplicationSession instances from within the same python process，没有让他们阻止。

问题已解决，但我遇到了一个新问题。

终止这些mp.Process个实例证明很难。我知道ApplicationRunner.run()中的代码会在KeyboardInterrupt上退出，但我无法正确触发此内容。

示例代码：

class PoloniexSession(ApplicationSession):

    @coroutine
    def onJoin(self, *args, **kwargs):
        channel = self.config.extra['channel']

        def onTicker(*args, **kwargs):
            self.config.extra['queue'].put((channel, (args, kwargs, time.time())))

        try:
            yield from self.subscribe(onTicker, self.config.extra['channel'])

        except Exception as e:
            raise


class PlnxEndpoint(mp.Process):
    def __init__(self, endpoint, q, **kwargs):
        super(PlnxEndpoint, self).__init__(name='%s Endpoint Process' %
                                                endpoint, **kwargs)
        self.endpoint = endpoint
        self.q = q

    def run(self):
        self.runner = ApplicationRunner("wss://api.poloniex.com:443", 'realm1',
                                   extra={'channel': self.endpoint, 
                                          'queue': self.q})
        self.runner.run(PoloniexSession)

    def join(self, *args, **kwargs):
        def sig_handler(x, y):
            pass
        signal.signal(signal.SIGINT, sig_handler)
        super(PlnxEndpoint, self).join(*args, **kwargs)


class PoloniexWSS(WSSAPI):
    def __init__(self, endpoints=None):
        super(PoloniexWSS, self).__init__(None, 'Poloniex')
        self.data_q = mp.Queue()
        self.connections = {}
        if endpoints:
            self.endpoints = endpoints
        else:
            r = requests.get('https://poloniex.com/public?command=returnTicker')
            self.endpoints = list(r.json().keys())
            self.endpoints.append('ticker')

        for endpoint in self.endpoints:
            self.connections[endpoint] = PlnxEndpoint(endpoint, self.data_q)

    def start(self):
        super(PoloniexWSS, self).start()
        for conn in self.connections:
            self.connections[conn].start()

    def stop(self):
        for conn in self.connections:
            self.connections[conn].join()
        super(PoloniexWSS, self).stop()

虽然这足以填充self.q，但是当我的子进程停止时仍然会收到错误：

RuntimeError: Event loop stopped before Future completed.
    Traceback (most recent call last):
  File "/home/nils/anaconda3/lib/python3.5/multiprocessing    /process.py", line 254, in _bootstrap
    self.run()
  File "/home/nils/git/tools/bitexwss/bitexws//api/poloniex.py", line 46, in run
    self.runner.run(PoloniexSession)
  File "/home/nils/anaconda3/lib/python3.5/site-packages/autobahn-0.14.1-py3.5.egg/autobahn/asyncio/wamp.py", line 172, in run
    loop.run_until_complete(protocol._session.leave())
  File "/home/nils/anaconda3/lib/python3.5/asyncio/base_events.py", line 335, in run_until_complete
    raise RuntimeError('Event loop stopped before Future completed.')

这让我相信我的signal.SIGINT并未在我想要的地方触发。

According to the source code of ApplicationRunner.run()，SIGINT / KeyboardInterrupt应优雅地结束serve_forever()方法。

手动关闭asyncio.event_loop也会导致上述错误：

class PlnxEndpoint(mp.Process):
#...
    def join(self, *args, **kwargs):
        loop = get_event_loop()
        loop.stop()
        super(PlnxEndpoint, self).join(*args, **kwargs)
#...

Answer 1

毕竟，一点点摆弄产生了一个相当简单的解决方案：

使用multiprocessing.Event()，我能够优雅地结束我的流程。

class PoloniexSession(ApplicationSession):

    @coroutine
    def onJoin(self, *args, **kwargs):
        channel = self.config.extra['channel']

        def onTicker(*args, **kwargs):
            self.config.extra['queue'].put((channel, (args, kwargs, time.time())))

        if self.config.extra['is_killed'].is_set():
            raise KeyboardInterrupt()
        try:
            yield from self.subscribe(onTicker, self.config.extra['channel'])

        except Exception as e:
            raise


class PlnxEndpoint(mp.Process):
    def __init__(self, endpoint, q, **kwargs):
        super(PlnxEndpoint, self).__init__(name='%s Endpoint Process' %
                                                endpoint, **kwargs)
        self.endpoint = endpoint
        self.q = q
        self.is_killed = mp.Event()

    def run(self):
        self.runner = ApplicationRunner("wss://api.poloniex.com:443", 'realm1',
                                   extra={'channel': self.endpoint,
                                          'queue': self.q,
                                          'is_killed': self.is_killed})
        self.runner.run(PoloniexSession)

    def join(self, *args, **kwargs):
        self.is_killed.set()
        super(PlnxEndpoint, self).join(*args, **kwargs)

使用signal.SIGINT正常终止Autobahn ApplicationRunner（）。run（）

1 个答案: