latest oslo.middleware causes: TypeError: 'NoneType' object is not iterable

[Dan Prince]

Using the latest oslo.middleware I'm now seeing the following errors when starting services like nova-api:

2015-11-19 22:44:48.348 29177 CRITICAL nova [-] TypeError: 'NoneType' object is not iterable
2015-11-19 22:44:48.348 29177 ERROR nova Traceback (most recent call last):
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/bin/nova-api", line 10, in <module>
2015-11-19 22:44:48.348 29177 ERROR nova sys.exit(main())
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/nova/cmd/api.py", line 55, in main
2015-11-19 22:44:48.348 29177 ERROR nova server = service.WSGIService(api, use_ssl=should_use_ssl)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/nova/service.py", line 353, in __init__
2015-11-19 22:44:48.348 29177 ERROR nova self.app = self.loader.load_app(name)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/nova/wsgi.py", line 544, in load_app
2015-11-19 22:44:48.348 29177 ERROR nova return deploy.loadapp("config:%s" % self.config_path, name=name)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 247, in loadapp
2015-11-19 22:44:48.348 29177 ERROR nova return loadobj(APP, uri, name=name, **kw)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 272, in loadobj
2015-11-19 22:44:48.348 29177 ERROR nova return context.create()
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 710, in create
2015-11-19 22:44:48.348 29177 ERROR nova return self.object_type.invoke(self)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 144, in invoke
2015-11-19 22:44:48.348 29177 ERROR nova **context.local_conf)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/util.py", line 59, in fix_call
2015-11-19 22:44:48.348 29177 ERROR nova reraise(*exc_info)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/compat.py", line 22, in reraise
2015-11-19 22:44:48.348 29177 ERROR nova exec('raise t, e, tb', dict(t=t, e=e, tb=tb))
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/util.py", line 56, in fix_call
2015-11-19 22:44:48.348 29177 ERROR nova val = callable(*args, **kw)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/nova/api/openstack/urlmap.py", line 160, in urlmap_factory
2015-11-19 22:44:48.348 29177 ERROR nova app = loader.get_app(app_name, global_conf=global_conf)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 350, in get_app
2015-11-19 22:44:48.348 29177 ERROR nova name=name, global_conf=global_conf).create()
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 710, in create
2015-11-19 22:44:48.348 29177 ERROR nova return self.object_type.invoke(self)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/loadwsgi.py", line 144, in invoke
2015-11-19 22:44:48.348 29177 ERROR nova **context.local_conf)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/util.py", line 59, in fix_call
2015-11-19 22:44:48.348 29177 ERROR nova reraise(*exc_info)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/compat.py", line 22, in reraise
2015-11-19 22:44:48.348 29177 ERROR nova exec('raise t, e, tb', dict(t=t, e=e, tb=tb))
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/paste/deploy/util.py", line 56, in fix_call
2015-11-19 22:44:48.348 29177 ERROR nova val = callable(*args, **kw)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/nova/api/auth.py", line 79, in pipeline_factory_v21
2015-11-19 22:44:48.348 29177 ERROR nova return _load_pipeline(loader, local_conf[CONF.auth_strategy].split())
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/nova/api/auth.py", line 62, in _load_pipeline
2015-11-19 22:44:48.348 29177 ERROR nova app = filter(app)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/oslo_middleware/base.py", line 47, in middleware_filter
2015-11-19 22:44:48.348 29177 ERROR nova return cls(app, conf)
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/oslo_middleware/cors.py", line 89, in __init__
2015-11-19 22:44:48.348 29177 ERROR nova self._init_conf()
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/oslo_middleware/cors.py", line 168, in _init_conf
2015-11-19 22:44:48.348 29177 ERROR nova self.add_origin(**self.oslo_conf[section])
2015-11-19 22:44:48.348 29177 ERROR nova File "/usr/lib/python2.7/site-packages/oslo_middleware/cors.py", line 183, in add_origin
2015-11-19 22:44:48.348 29177 ERROR nova for origin in allowed_origin:
2015-11-19 22:44:48.348 29177 ERROR nova TypeError: 'NoneType' object is not iterable
2015-11-19 22:44:48.348 29177 ERROR nova

----

The issue seems to be that in c4957606cb290a639a4a02fbf648044242c5c207 we made allowed_origin a list... but not all of the oslo.middleware checks respect the default value being None.

[ChangBo Guo(gcb) (glongwave)]

oslo.middleware Fix Proposed in https://review.openstack.org/#/c/247831/