Cumulocity - CumulocityLongPollingTransport空闲

Question

我使用7.40.0 Cumulocity Java客户端SDK订阅实时通知。我可以获得通知，但在让客户端运行一段时间后，它似乎停止了侦听，并且我不再能够检索通知。

有没有人遇到过这种情况？

WARN  2017-01-03 08:44:49,727 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.ConnectionHeartBeatWatcher: canceling the long poll request because of inactivity
DEBUG 2017-01-03 08:44:49,727 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: canceling [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=16, connectionType=long-polling}]
DEBUG 2017-01-03 08:44:49,727 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: stopping heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=16, connectionType=long-polling}]
DEBUG 2017-01-03 08:44:50,728 [pool-21-thread-1] com.cumulocity.sdk.client.notification.CumulocityLongPollingTransport.1365985548: sending messages [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=19, connectionType=long-polling}] 
DEBUG 2017-01-03 08:44:50,728 [pool-21-thread-1] com.cumulocity.sdk.client.notification.MessageExchange: starting heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=19, connectionType=long-polling}]
DEBUG 2017-01-03 08:44:51,710 [CumulocityLongPollingTransport-scheduler-1] com.cumulocity.sdk.client.notification.MessageExchange: wait for response headers [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=19, connectionType=long-polling}]
DEBUG 2017-01-03 08:44:51,710 [CumulocityLongPollingTransport-scheduler-1] com.cumulocity.sdk.client.notification.MessageExchange: recived response headers [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=19, connectionType=long-polling}] 
DEBUG 2017-01-03 08:44:51,710 [CumulocityLongPollingTransport-scheduler-1] com.cumulocity.sdk.client.notification.MessageExchange: getting heartbeants  POST https://msc.cumulocity.com//cep/realtime returned a response status of 200 OK
DEBUG 2017-01-03 08:44:51,710 [CumulocityLongPollingTransport-scheduler-1] com.cumulocity.sdk.client.notification.MessageExchange: new messages recived
DEBUG 2017-01-03 08:44:51,711 [CumulocityLongPollingTransport-scheduler-1] com.cumulocity.sdk.client.notification.MessageExchange: Received messages [{channel=/meta/connect, id=19, advice={reconnect=retry, interval=0, timeout=5400000}, successful=true}]
DEBUG 2017-01-03 08:44:51,711 [CumulocityLongPollingTransport-scheduler-1] com.cumulocity.sdk.client.notification.MessageExchange: stopping heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=19, connectionType=long-polling}]
DEBUG 2017-01-03 08:44:51,711 [pool-21-thread-1] com.cumulocity.sdk.client.notification.CumulocityLongPollingTransport.1365985548: sending messages [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=23, connectionType=long-polling}] 
DEBUG 2017-01-03 08:44:51,711 [pool-21-thread-1] com.cumulocity.sdk.client.notification.MessageExchange: starting heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=23, connectionType=long-polling}]
DEBUG 2017-01-03 08:56:51,711 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: canceling [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=23, connectionType=long-polling}]
DEBUG 2017-01-03 08:56:51,711 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: stopping heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=23, connectionType=long-polling}]
DEBUG 2017-01-03 08:56:52,711 [pool-21-thread-1] com.cumulocity.sdk.client.notification.CumulocityLongPollingTransport.1365985548: sending messages [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=26, connectionType=long-polling}] 
DEBUG 2017-01-03 08:56:52,712 [pool-21-thread-1] com.cumulocity.sdk.client.notification.MessageExchange: starting heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=26, connectionType=long-polling}]
DEBUG 2017-01-03 08:56:53,659 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: wait for response headers [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=26, connectionType=long-polling}]
DEBUG 2017-01-03 08:56:53,659 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: recived response headers [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=26, connectionType=long-polling}] 
DEBUG 2017-01-03 08:56:53,659 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: getting heartbeants  POST https://msc.cumulocity.com//cep/realtime returned a response status of 200 OK
DEBUG 2017-01-03 08:56:53,660 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: new messages recived
DEBUG 2017-01-03 08:56:53,661 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: Received messages [{channel=/meta/connect, id=26, advice={reconnect=retry, interval=0, timeout=5400000}, successful=true}]
DEBUG 2017-01-03 08:56:53,661 [CumulocityLongPollingTransport-scheduler-0] com.cumulocity.sdk.client.notification.MessageExchange: stopping heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, advice={timeout=0}, channel=/meta/connect, id=26, connectionType=long-polling}]
DEBUG 2017-01-03 08:56:53,661 [pool-21-thread-1] com.cumulocity.sdk.client.notification.CumulocityLongPollingTransport.1365985548: sending messages [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=28, connectionType=long-polling}] 
DEBUG 2017-01-03 08:56:53,661 [pool-21-thread-1] com.cumulocity.sdk.client.notification.MessageExchange: starting heartbeat watcher [{clientId=4b11irnlptb55g4rs3hauu1ctjpy, channel=/meta/connect, id=28, connectionType=long-polling}]

Answer 1

当您的中间网络设备配置为丢弃或减少网络流量以实现持久连接时，可能会出现这种情况。公司HTTP代理就是一个例子，但移动网络提供商也可能具有这样的配置。

这很难排除，通常您必须使用低级别的wireshark或网络协议方法。我们在以下机制方面取得了成功：

• 使用不同的网络，例如，直接DSL线，而不是公司Intranet.
• Raise与您的IT或网络提供商的票证，以避免过早切断连接或不丢弃数据包。
• 如果您自己正在运行Cumulocity，则可以将其配置为更频繁地发送服务器端检测信号。这使得中间网络设备将连接视为实时连接，但代价是所有客户端的额外流量。
• 使用MQTT并设置更高的ping速率。

很抱歉这里没有简单的答案:-)

Answer 2

我也有过同样的经历。显然，在我们的例子中，一些中间盒在服务器发送keepalive数据包之前丢弃了长轮询TCP连接(默认情况下是在10分钟后)。

此外，当使用7.26版本的Java参考代理进行测试时，我们看到，如果代理没有接收到服务器端的keepalives，它会在三次尝试后停止重新建立长轮询连接。我还没有检查这在以后的版本中是否发生了变化。

我们运行自己的Cumulocity实例，并且能够配置服务器端的keepalive计时器。我们将keepalive计时器设置为3分钟，解决了这个问题。