From 7a427bcd2aa3dc444c8362429405786dde21d2f0 Mon Sep 17 00:00:00 2001
From: Rodolfo Alonso Hernandez <ralonsoh@redhat.com>
Date: Fri, 3 Jul 2020 10:47:52 +0000
Subject: [PATCH] Remove _router_exists  method

Instead of retrieving the full DB object, "objects_exist" OVO method
will be faster.

Trivial-Fix

Change-Id: Iaf08c75d6a3721c05db9e3858c0136847b0102a6
---
 neutron/db/l3_db.py                     | 10 ++--------
 neutron/tests/unit/db/test_l3_db.py     |  7 +++----
 neutron/tests/unit/db/test_l3_dvr_db.py | 10 +++++-----
 3 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/neutron/db/l3_db.py b/neutron/db/l3_db.py
index adca7d700ae..08a5528f14e 100644
--- a/neutron/db/l3_db.py
+++ b/neutron/db/l3_db.py
@@ -1517,13 +1517,6 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase,
         filters = filters or {}
         return l3_obj.FloatingIP.count(context, **filters)
 
-    def _router_exists(self, context, router_id):
-        try:
-            self.get_router(context.elevated(), router_id)
-            return True
-        except l3_exc.RouterNotFound:
-            return False
-
     def prevent_l3_port_deletion(self, context, port_id):
         """Checks to make sure a port is allowed to be deleted.
 
@@ -1561,7 +1554,8 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase,
                           "%(port_id)s no longer exists, allowing deletion.",
                           {'f_id': port['device_id'], 'port_id': port['id']})
                 return
-        elif not self._router_exists(context, port['device_id']):
+        elif not l3_obj.Router.objects_exist(context.elevated(),
+                                             id=port['device_id']):
             LOG.debug("Router %(router_id)s corresponding to port "
                       "%(port_id)s no longer exists, allowing deletion.",
                       {'router_id': port['device_id'],
diff --git a/neutron/tests/unit/db/test_l3_db.py b/neutron/tests/unit/db/test_l3_db.py
index 5111621fa0f..eeff600df4c 100644
--- a/neutron/tests/unit/db/test_l3_db.py
+++ b/neutron/tests/unit/db/test_l3_db.py
@@ -22,7 +22,6 @@ from neutron_lib.callbacks import resources
 from neutron_lib import constants as n_const
 from neutron_lib import context
 from neutron_lib import exceptions as n_exc
-from neutron_lib.exceptions import l3 as l3_exc
 from neutron_lib.plugins import constants as plugin_constants
 from neutron_lib.plugins import directory
 from neutron_lib.plugins import utils as plugin_utils
@@ -217,9 +216,9 @@ class TestL3_NAT_dbonly_mixin(base.BaseTestCase):
             'device_owner': n_const.DEVICE_OWNER_ROUTER_INTF,
             'device_id': '44', 'id': 'f',
             'fixed_ips': [{'ip_address': '1.1.1.1', 'subnet_id': '4'}]}
-        self.db.get_router = mock.Mock()
-        self.db.get_router.side_effect = l3_exc.RouterNotFound(router_id='44')
-        self.db.prevent_l3_port_deletion(mock.Mock(), None)
+        with mock.patch.object(l3_obj.Router, 'objects_exist',
+                               return_value=False):
+            self.db.prevent_l3_port_deletion(mock.Mock(), None)
 
     @mock.patch.object(directory, 'get_plugin')
     def test_prevent_l3_port_existing_router(self, gp):
diff --git a/neutron/tests/unit/db/test_l3_dvr_db.py b/neutron/tests/unit/db/test_l3_dvr_db.py
index 76c95ca48ca..9f90810b114 100644
--- a/neutron/tests/unit/db/test_l3_dvr_db.py
+++ b/neutron/tests/unit/db/test_l3_dvr_db.py
@@ -347,11 +347,11 @@ class L3DvrTestCase(test_db_base_plugin_v2.NeutronDbPluginV2TestCase):
         plugin = mock.Mock()
         directory.add_plugin(plugin_constants.CORE, plugin)
         plugin.get_port.return_value = port
-        self.mixin._router_exists = mock.Mock(return_value=True)
-        self.assertRaises(exceptions.ServicePortInUse,
-                          self.mixin.prevent_l3_port_deletion,
-                          self.ctx,
-                          port['id'])
+        with mock.patch.object(router_obj.Router, 'objects_exist',
+                               return_value=True):
+            self.assertRaises(exceptions.ServicePortInUse,
+                              self.mixin.prevent_l3_port_deletion,
+                              self.ctx, port['id'])
 
     def test_prevent_delete_floatingip_agent_gateway_port(self):
         port = {