More useful message when using direct driver import

In the Liberty release, we switched to using entrypoints for
specifying the driver or auth plugin. The deprecation message
didn't mention the driver name that was specified, nor did it
mention where to look for the expected names, so it was not
user friendly.

Closes-Bug: 1513102
Change-Id: I02e265684b26686523da9d648b37675feb052978

keystone/auth/controllers.py

@@ -45,8 +45,8 @@ AUTH_PLUGINS_LOADED = False
 
 def load_auth_method(method):
     plugin_name = CONF.auth.get(method) or 'default'
+    namespace = 'keystone.auth.%s' % method
     try:
-        namespace = 'keystone.auth.%s' % method
         driver_manager = stevedore.DriverManager(namespace, plugin_name,
                                                  invoke_on_load=True)
         return driver_manager.driver
@@ -55,13 +55,16 @@ def load_auth_method(method):
                   'attempt to load using import_object instead.',
                   method, plugin_name)
 
-    @versionutils.deprecated(as_of=versionutils.deprecated.LIBERTY,
-                             in_favor_of='entrypoints',
-                             what='direct import of driver')
-    def _load_using_import(plugin_name):
-        return importutils.import_object(plugin_name)
+    driver = importutils.import_object(plugin_name)
 
-    return _load_using_import(plugin_name)
+    msg = (_(
+        'Direct import of auth plugin %(name)r is deprecated as of Liberty in '
+        'favor of its entrypoint from %(namespace)r and may be removed in '
+        'N.') %
+        {'name': plugin_name, 'namespace': namespace})
+    versionutils.report_deprecated_feature(LOG, msg)
+
+    return driver
 
 
 def load_auth_methods():

keystone/common/manager.py

@@ -19,6 +19,8 @@ from oslo_log import versionutils
 from oslo_utils import importutils
 import stevedore
 
+from keystone.i18n import _
+
 
 LOG = log.getLogger(__name__)
 
@@ -70,15 +72,16 @@ def load_driver(namespace, driver_name, *args):
         LOG.debug('Failed to load %r using stevedore: %s', driver_name, e)
         # Ignore failure and continue on.
 
-    @versionutils.deprecated(as_of=versionutils.deprecated.LIBERTY,
-                             in_favor_of='entrypoints',
-                             what='direct import of driver')
-    def _load_using_import(driver_name, *args):
-        return importutils.import_object(driver_name, *args)
+    driver = importutils.import_object(driver_name, *args)
 
-    # For backwards-compatibility, an unregistered class reference can
-    # still be used.
-    return _load_using_import(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
 
 
 class Manager(object):