Remove loading drivers outside of their expected namespaces

Direct import of drivers was deprecated in the Liberty release and
planned for removal during Newton.

In other words, identity drivers must be imported from the
`keystone.identity` namespace, assignment drivers from the
`keystone.assignment` namespace, etc.

Also this catches a more specific exception from stevedore
rather than just RuntimeError.

blueprint removed-as-of-pike

Change-Id: If5e581b249700d8e4683ecfab15ba86da85f1052

keystone/common/manager.py

@@ -18,8 +18,6 @@ import time
 import types
 
 from oslo_log import log
-from oslo_log import versionutils
-from oslo_utils import importutils
 import six
 import stevedore
 
@@ -72,20 +70,9 @@ def load_driver(namespace, driver_name, *args):
                                                  invoke_on_load=True,
                                                  invoke_args=args)
         return driver_manager.driver
-    except RuntimeError as e:
-        LOG.debug('Failed to load %r using stevedore: %s', driver_name, e)
-        # Ignore failure and continue on.
-
-    driver = importutils.import_object(driver_name, *args)
-
-    msg = (_(
-        'Direct import of driver %(name)r is deprecated as of Liberty in '
-        'favor of its entrypoint from %(namespace)r and may be removed in '
-        'N.') %
-        {'name': driver_name, 'namespace': namespace})
-    versionutils.report_deprecated_feature(LOG, msg)
-
-    return driver
+    except stevedore.exception.NoMatches:
+        msg = (_('Unable to find %(name)r driver in %(namespace)r.'))
+        raise ImportError(msg, {'name': driver_name, 'namespace': namespace})
 
 
 class _TraceMeta(type):

keystone/tests/unit/test_token_provider.py

@@ -762,7 +762,7 @@ class TestTokenProvider(unit.TestCase):
 
     def test_unsupported_token_provider(self):
         self.config_fixture.config(group='token',
-                                   provider='my.package.MyProvider')
+                                   provider='MyProvider')
         self.assertRaises(ImportError,
                           token.provider.Manager)
 

releasenotes/notes/removed-as-of-pike-deadbeefdeadbeef.yaml

@@ -36,3 +36,10 @@ other:
     The ``keystone-manage pki_setup`` was added to aid developer setup by hiding the sometimes cryptic
     openssl commands. This is no longer needed since keystone no longer supports PKI tokens and can no
     longer serve SSL. This was deprecated in the Mitaka release.
+  - >
+    [`blueprint removed-as-of-pike <https://blueprints.launchpad.net/keystone/+spec/removed-as-of-pike>`_]
+    Direct import of drivers outside of their `keystone` namespace has been
+    removed. Ex. identity drivers are loaded from the `keystone.identity`
+    namespace and assignment drivers from the `keystone.assignment` namespace.
+    Loading drivers outside of their keystone namespaces was deprecated in the
+    Liberty release.