Enable use of service user token with admin context

When the [service_user] section is configured in nova.conf, nova will
have the ability to send a service user token alongside the user's
token. The service user token is sent when nova calls other services'
REST APIs to authenticate as a service, and service calls can sometimes
have elevated privileges.

Currently, nova does not however have the ability to send a service user
token with an admin context. This means that when nova makes REST API
calls to other services with an anonymous admin RequestContext (such as
in nova-manage or periodic tasks), it will not be authenticated as a
service.

This adds a keyword argument to service_auth.get_auth_plugin() to
enable callers to provide a user_auth object instead of attempting to
extract the user_auth from the RequestContext.

The cinder and neutron client modules are also adjusted to make use of
the new user_auth keyword argument so that nova calls made with
anonymous admin request contexts can authenticate as a service when
configured.

Related-Bug: #2004555

Change-Id: I14df2d55f4b2f0be58f1a6ad3f19e48f7a6bfcb4
(cherry picked from commit 41c64b94b0)

nova/network/neutron.py

@@ -222,13 +222,15 @@ def _get_auth_plugin(context, admin=False):
     # support some services (metadata API) where an admin context is used
     # without an auth token.
     global _ADMIN_AUTH
+    user_auth = None
     if admin or (context.is_admin and not context.auth_token):
         if not _ADMIN_AUTH:
             _ADMIN_AUTH = _load_auth_plugin(CONF)
-        return _ADMIN_AUTH
+        user_auth = _ADMIN_AUTH
 
-    if context.auth_token:
-        return service_auth.get_auth_plugin(context)
+    if context.auth_token or user_auth:
+        # When user_auth = None, user_auth will be extracted from the context.
+        return service_auth.get_auth_plugin(context, user_auth=user_auth)
 
     # We did not get a user token and we should not be using
     # an admin token so log an error

nova/service_auth.py

@@ -30,8 +30,10 @@ def reset_globals():
     _SERVICE_AUTH = None
 
 
-def get_auth_plugin(context):
-    user_auth = context.get_auth_plugin()
+def get_auth_plugin(context, user_auth=None):
+    # user_auth may be passed in when the RequestContext is anonymous, such as
+    # when get_admin_context() is used for API calls by nova-manage.
+    user_auth = user_auth or context.get_auth_plugin()
 
     if CONF.service_user.send_service_user_token:
         global _SERVICE_AUTH

nova/tests/unit/network/test_neutron.py

@@ -142,6 +142,22 @@ class TestNeutronClient(test.NoDBTestCase):
         self.assertIsInstance(cl.httpclient.auth,
                               service_token.ServiceTokenAuthWrapper)
 
+    @mock.patch('nova.service_auth._SERVICE_AUTH')
+    @mock.patch('nova.network.neutron._ADMIN_AUTH')
+    @mock.patch.object(ks_loading, 'load_auth_from_conf_options')
+    def test_admin_with_service_token(
+        self, mock_load, mock_admin_auth, mock_service_auth
+    ):
+        self.flags(send_service_user_token=True, group='service_user')
+
+        admin_context = context.get_admin_context()
+
+        cl = neutronapi.get_client(admin_context)
+        self.assertIsInstance(cl.httpclient.auth,
+                              service_token.ServiceTokenAuthWrapper)
+        self.assertEqual(mock_admin_auth, cl.httpclient.auth.user_auth)
+        self.assertEqual(mock_service_auth, cl.httpclient.auth.service_auth)
+
     @mock.patch.object(client.Client, "list_networks",
                        side_effect=exceptions.Unauthorized())
     def test_Unauthorized_user(self, mock_list_networks):

nova/tests/unit/test_service_auth.py

@@ -56,3 +56,13 @@ class ServiceAuthTestCase(test.NoDBTestCase):
         result = service_auth.get_auth_plugin(self.ctx)
         self.assertEqual(1, mock_load.call_count)
         self.assertNotIsInstance(result, service_token.ServiceTokenAuthWrapper)
+
+    @mock.patch.object(ks_loading, 'load_auth_from_conf_options',
+                       new=mock.Mock())
+    def test_get_auth_plugin_user_auth(self):
+        self.flags(send_service_user_token=True, group='service_user')
+        user_auth = mock.Mock()
+
+        result = service_auth.get_auth_plugin(self.ctx, user_auth=user_auth)
+
+        self.assertEqual(user_auth, result.user_auth)

nova/tests/unit/volume/test_cinder.py

@@ -1276,3 +1276,14 @@ class CinderClientTestCase(test.NoDBTestCase):
         admin_ctx = context.get_admin_context()
         params = cinder._get_cinderclient_parameters(admin_ctx)
         self.assertEqual(params[0], mock_admin_auth)
+
+    @mock.patch('nova.service_auth._SERVICE_AUTH')
+    @mock.patch('nova.volume.cinder._ADMIN_AUTH')
+    def test_admin_context_without_user_token_but_with_service_token(
+        self, mock_admin_auth, mock_service_auth
+    ):
+        self.flags(send_service_user_token=True, group='service_user')
+        admin_ctx = context.get_admin_context()
+        params = cinder._get_cinderclient_parameters(admin_ctx)
+        self.assertEqual(mock_admin_auth, params[0].user_auth)
+        self.assertEqual(mock_service_auth, params[0].service_auth)

nova/volume/cinder.py

@@ -91,12 +91,14 @@ def _get_auth(context):
     # from them generated from 'context.get_admin_context'
     # which only set is_admin=True but is without token.
     # So add load_auth_plugin when this condition appear.
+    user_auth = None
     if context.is_admin and not context.auth_token:
         if not _ADMIN_AUTH:
             _ADMIN_AUTH = _load_auth_plugin(CONF)
-        return _ADMIN_AUTH
-    else:
-        return service_auth.get_auth_plugin(context)
+        user_auth = _ADMIN_AUTH
+
+    # When user_auth = None, user_auth will be extracted from the context.
+    return service_auth.get_auth_plugin(context, user_auth=user_auth)
 
 
 # NOTE(efried): Bug #1752152