500 error during queues list when pool enabled and no queue

[Feilong Wang]

User will run into a 500 error when there is no queue under the tenant and pool enabled, see below error:

Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/usr/local/lib/python2.7/dist-packages/keystonemiddleware/auth_token.py", line 748, in __call__
    return self._call_app(env, start_response)
  File "/usr/local/lib/python2.7/dist-packages/keystonemiddleware/auth_token.py", line 684, in _call_app
    return self._app(env, _fake_start_response)
  File "/usr/local/lib/python2.7/dist-packages/falcon/api.py", line 96, in __call__
    responder(req, resp, **params) # pragma: no cover
  File "/usr/local/lib/python2.7/dist-packages/falcon/api_helpers.py", line 262, in do_before
    responder(req, resp, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/falcon/api_helpers.py", line 262, in do_before
    responder(req, resp, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/falcon/api_helpers.py", line 262, in do_before
    responder(req, resp, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/falcon/api_helpers.py", line 262, in do_before
    responder(req, resp, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/falcon/api_helpers.py", line 262, in do_before
    responder(req, resp, **kwargs)
  File "/home/feilong/MyWorkspace/workspace_community/zaqar/zaqar/transport/wsgi/v2_0/queues.py", line 148, in on_get
    kwargs['marker'] = next(results) or kwargs.get('marker', '')
  File "/home/feilong/MyWorkspace/workspace_community/zaqar/zaqar/storage/pooling.py", line 169, in _list
    yield marker_name['next']
KeyError: 'next'
127.0.0.1 - - [20/Jan/2015 13:57:30] "GET /v2/queues/ HTTP/1.1" 500 59

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/148396

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/148396
Committed: https://git.openstack.org/cgit/openstack/zaqar/commit/?id=2649062d80bb9b996ba82791d69a54497f5b9e81
Submitter: Jenkins
Branch: master

commit 2649062d80bb9b996ba82791d69a54497f5b9e81
Author: Fei Long Wang <email address hidden>
Date: Tue Jan 20 13:58:28 2015 +1300

    Check marker before accessing it

    When pool is enabled, current code will return marker_name['next']
    no matter if there is the key 'next' in it. Then user will run
    into a KeyError issue. This fix will change it and keep it
    consistent with the behaviour of no pool.

    Closes-Bug: #1412608

    Change-Id: Iea66f99482146c38615fccc3060ab56f7ff98d9e