[2.1a2] errors during network observation processes can result in a process leak

[Gavin Panella]

2016-09-06 09:55:28 [-] unexpected error in processEnded
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/twisted/internet/process.py", line 960, in maybeCallProcessEnded
    self.reapProcess()
  File "/usr/lib/python3/dist-packages/twisted/internet/process.py", line 335, in reapProcess
    self.processEnded(status)
  File "/usr/lib/python3/dist-packages/twisted/internet/_baseprocess.py", line 52, in processEnded
    self.maybeCallProcessEnded()
  File "/usr/lib/python3/dist-packages/twisted/internet/process.py", line 962, in maybeCallProcessEnded
    _BaseProcess.maybeCallProcessEnded(self)
--- <exception caught here> ---
  File "/usr/lib/python3/dist-packages/twisted/internet/_baseprocess.py", line 64, in maybeCallProcessEnded
    proto.processEnded(Failure(reason))
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/services.py", line 109, in processEnded
    self.done.errback(reason)
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 434, in errback
    self._startRunCallbacks(fail)
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 494, in _startRunCallbacks
    raise AlreadyCalledError
twisted.internet.defer.AlreadyCalledError:

Using 2.1.0~alpha2+bzr5321-0ubuntu1~16.04.2.

[Mike Pontillo (mpontillo)]

Thanks; clearly some additional testing is needed around the process lifecycle.