AttributeError: 'AsyncResult' object has no attribute 'link'

[timothykang]

Encountered on PlatformHistorianAgent start:

Traceback (most recent call last):
  File "~/volttron/env/lib/python2.7/site-packages/gevent/greenlet.py", line 327, in run
    result = self._run(*self.args, **self.kwargs)
  File "~/.volttron/agents/bba29e1b-6510-495f-811b-15257baad78c/platform_historianagent-0.1/platform_historian/agent.py", line 98, in starting
    self.vip.pubsub.subscribe('pubsub', '/platform', self.__platform)
  File "~/volttron/volttron/platform/vipagent/subsystems/pubsub.py", line 278, in subscribe
    result.link(finish)
AttributeError: 'AsyncResult' object has no attribute 'link'
<Greenlet at 0x1090a0410: <bound method SQLiteHistorianAgent.starting of <platform_historian.agent.SQLiteHistorianAgent object at 0x109092810>>(<volttron.platform.vipagent.core.Core object at 0x)> failed with AttributeError

[craig8]

This issue happens when attempting to register a listener (i.e. subscribe) to the topic /platform on the pubsub peer.

Currently the work around is to make sure that there is a platform agent running on the volttron instance before starting the historian service. Then the code in question should not get triggered.

With that being said the issue is that the subscription to the /platform topic is not being handled properly and that will need to be investigated. I am composing an email to @hashstat for this and a broader issue that might have to do with this issue as well.

[hashstat]

Fixed by 31308042f8367cbf1645cd7d07dd004c3d9636ab.