Add MongoDB cluster root-enable support

Root access is needed to be able to shrink MongoDB clusters that have
role-based access control enabled. Without it, shrink isn't possible.

Following the approach implemented for Vertica, add an extension for
MongoDB root management. Also include an optional guard against running
root-enable against individual cluster instances.

Change-Id: I1a3b221ecf575b0389e871fb246d5cd633abc56f
Closes-bug: #1554659

trove/common/cfg.py

@@ -988,7 +988,8 @@ mongodb_opts = [
                help='Maximum time to wait (in seconds) for a replica set '
                     'initialization process to complete.'),
     cfg.StrOpt('root_controller',
-               default='trove.extensions.common.service.DefaultRootController',
+               default='trove.extensions.mongodb.service.'
+                       'MongoDBRootController',
                help='Root controller implementation for mongodb.'),
     cfg.StrOpt('guest_log_exposed_logs', default='',
                help='List of Guest Logs to expose for publishing.'),

trove/extensions/common/service.py

@@ -129,10 +129,20 @@ class ClusterRootController(DefaultRootController):
             tenant_id, cluster_id)
         return self.instance_root_index(req, tenant_id, single_instance_id)
 
+    def _block_cluster_instance_actions(self):
+        return False
+
+    def check_cluster_instance_actions(self, instance_id):
+        # Check if instance is in a cluster and if actions are allowed
+        instance = DBInstance.find_by(id=instance_id)
+        if instance.cluster_id and self._block_cluster_instance_actions():
+            raise exception.ClusterInstanceOperationNotSupported()
+
     def root_create(self, req, body, tenant_id, instance_id, is_cluster):
         if is_cluster:
             return self.cluster_root_create(req, body, tenant_id, instance_id)
         else:
+            self.check_cluster_instance_actions(instance_id)
             return self.instance_root_create(req, body, instance_id)
 
     def instance_root_create(self, req, body, instance_id,

trove/extensions/mongodb/service.py

@@ -0,0 +1,47 @@
+# Copyright 2015 Tesora Inc.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_log import log as logging
+
+from trove.common import cfg
+from trove.common import exception
+from trove.extensions.common.service import ClusterRootController
+from trove.instance.models import DBInstance
+
+LOG = logging.getLogger(__name__)
+CONF = cfg.CONF
+MANAGER = CONF.datastore_manager if CONF.datastore_manager else 'mongodb'
+
+
+class MongoDBRootController(ClusterRootController):
+
+    def delete(self, req, tenant_id, instance_id):
+        raise exception.DatastoreOperationNotSupported(
+            operation='disable_root', datastore=MANAGER)
+
+    def _block_cluster_instance_actions(self):
+        return True
+
+    def _find_query_router_ids(self, tenant_id, cluster_id):
+        args = {'tenant_id': tenant_id, 'cluster_id': cluster_id,
+                'type': 'query_router'}
+        query_router_instances = DBInstance.find_all(**args).all()
+        return [db_instance.id for db_instance in query_router_instances]
+
+    def _get_cluster_instance_id(self, tenant_id, cluster_id):
+        instance_ids = self._find_cluster_node_ids(tenant_id, cluster_id)
+        single_instance_id = self._find_query_router_ids(tenant_id,
+                                                         cluster_id)[0]
+        return single_instance_id, instance_ids

trove/tests/unittests/common/test_common_extensions.py

@@ -190,14 +190,16 @@ class TestClusterRootController(trove_testtools.TestCase):
         self.controller.root_create(req, body, tenant_id, uuid, is_cluster)
         mock_cluster_root_create.assert_called_with(req, body, tenant_id, uuid)
 
+    @patch.object(ClusterRootController, "check_cluster_instance_actions")
     @patch.object(ClusterRootController, "instance_root_create")
-    def test_root_create_instance(self, mock_instance_root_create):
+    def test_root_create_instance(self, mock_instance_root_create, mock_check):
         req = Mock()
         body = Mock()
         tenant_id = Mock()
         uuid = utils.generate_uuid()
         is_cluster = False
         self.controller.root_create(req, body, tenant_id, uuid, is_cluster)
+        mock_check.assert_called_with(uuid)
         mock_instance_root_create.assert_called_with(req, body, uuid)
 
     @patch.object(models.ClusterRoot, "load")