When specify token provoider as "pkiz" instead of full class path of token provider as "keystone.token.providers.[pkiz|pki|uuid].Provider" in keystone.conf I will get the following exception thrown in the log file.
2014-12-14 04:48:18.710721 Traceback (most recent call last):
2014-12-14 04:48:18.710732 File "/var/www/keystone/main", line 53, in <module>
2014-12-14 04:48:18.710798 drivers = backends.load_backends()
2014-12-14 04:48:18.710817 File "/opt/stack/keystone/keystone/backends.py", line 48, in load_backends
2014-12-14 04:48:18.710851 token_provider_api=token.provider.Manager())
2014-12-14 04:48:18.710867 File "/opt/stack/keystone/keystone/common/dependency.py", line 200, in wrapper
2014-12-14 04:48:18.710944 self.__wrapped_init__(*args, **kwargs)
2014-12-14 04:48:18.710950 File "/opt/stack/keystone/keystone/common/dependency.py", line 110, in __wrapped_init__
2014-12-14 04:48:18.710969 init(self, *args, **kwargs)
2014-12-14 04:48:18.710974 File "/opt/stack/keystone/keystone/token/provider.py", line 152, in __init__
2014-12-14 04:48:18.711100 super(Manager, self).__init__(self.get_token_provider())
2014-12-14 04:48:18.711106 File "/opt/stack/keystone/keystone/common/manager.py", line 70, in __init__
2014-12-14 04:48:18.711150 self.driver = importutils.import_object(driver_name)
2014-12-14 04:48:18.711165 File "/usr/local/lib/python2.7/dist-packages/oslo/utils/importutils.py", line 38, in import_object
2014-12-14 04:48:18.711226 return import_class(import_str)(*args, **kwargs)
2014-12-14 04:48:18.711244 File "/usr/local/lib/python2.7/dist-packages/oslo/utils/importutils.py", line 27, in import_class
2014-12-14 04:48:18.711252 __import__(mod_str)
2014-12-14 04:48:18.711264 ValueError: Empty module name
I understand the comment in "keystone.conf" has show us how to config the provider but in my opinion, it should also support "pkiz|pki|uuid" besides the full class path, or at least, there should be one dedicated exception to show us what's wrong with the config. Seen from the code there is no invalid provider checking, so invalid token provider exception to show us what's wrong with the config is desired.
This is a problem that we've had with *all* of our drivers loading. This is not exclusive to the token provider. The dedicated exception is a good idea, we should move away from the full-class path and move to stevedore longer term.