Add a setting for disabling dhcp agents column in the admin network view

Retrieving that information for every network can take considerable time
on large deployments with large number of networks, and for some kinds
of network drivers (ovn binary) this will be always zero anyways.

This setting lets us disable that column to speed up the networks view.

Change-Id: I1f1561916067d3f4a02f10ec9f62e8ba777a1501

doc/source/configuration/settings.rst

@@ -1853,6 +1853,7 @@ Default:
         'segmentation_id_range': {},
         'supported_provider_types': ["*"],
         'supported_vnic_types': ["*"],
+        'show_agents_column': True,
     }
 
 A dictionary of settings which can be used to enable optional services provided
@@ -2104,6 +2105,19 @@ Example: ``['normal', 'direct']``
 
 To disable VNIC type selection, set an empty list (``[]``) or ``None``.
 
+show_agents_column
+##################
+
+.. versionadded:: 2024.1(Caracal)
+
+Default ``True``
+
+Decides whether the DHCP Agents column should be shown on the Admin Networks
+panel. Retrieving data for that column takes time, and it may be advisable to
+disable it on large deployments with a large number on networks to speed up
+displaying of that view.
+
+
 Nova
 ----
 

openstack_dashboard/dashboards/admin/networks/tables.py

@@ -22,9 +22,13 @@ from horizon import exceptions
 from horizon import tables
 
 from openstack_dashboard import api
+from openstack_dashboard.dashboards.admin.networks \
+    import utils as admin_utils
 from openstack_dashboard.dashboards.project.networks \
     import tables as project_tables
 from openstack_dashboard import policy
+from openstack_dashboard.utils import settings as setting_utils
+
 
 LOG = logging.getLogger(__name__)
 
@@ -117,12 +121,9 @@ class NetworksTable(tables.DataTable):
                     "is supported")
             exceptions.handle(self.request, msg)
             del self.columns['availability_zones']
-        try:
-            if not api.neutron.is_extension_supported(request,
-                                                      'dhcp_agent_scheduler'):
-                del self.columns['num_agents']
-        except Exception:
-            msg = _("Unable to check if DHCP agent scheduler "
-                    "extension is supported")
-            exceptions.handle(self.request, msg)
+
+        show_agents_column = setting_utils.get_dict_config(
+            'OPENSTACK_NEUTRON_NETWORK', 'show_agents_column')
+        if not (show_agents_column and
+                admin_utils.is_dhcp_agent_scheduler_supported(request)):
             del self.columns['num_agents']

openstack_dashboard/dashboards/admin/networks/tests.py

@@ -68,9 +68,10 @@ class NetworkTests(test.BaseAdminViewTests):
             test.IsHttpRequest(), single_page=True,
             limit=21, sort_dir='asc', sort_key='id')
         self.mock_tenant_list.assert_called_once_with(test.IsHttpRequest())
-        self._check_is_extension_supported(
-            {'network_availability_zone': 1,
-             'dhcp_agent_scheduler': len(self.networks.list()) + 1})
+        self._check_is_extension_supported({
+            'network_availability_zone': 1,
+            'dhcp_agent_scheduler': 2,
+        })
         self.mock_list_dhcp_agent_hosting_networks.assert_has_calls(
             [mock.call(test.IsHttpRequest(), network.id)
              for network in self.networks.list()])

openstack_dashboard/dashboards/admin/networks/utils.py

@@ -0,0 +1,27 @@
+#    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 horizon import exceptions
+
+from openstack_dashboard import api
+
+
+def is_dhcp_agent_scheduler_supported(request):
+    try:
+        if api.neutron.is_extension_supported(
+                request, 'dhcp_agent_scheduler'):
+            return True
+    except Exception:
+        msg = _("Unable to check if DHCP agent scheduler "
+                "extension is supported")
+        exceptions.handle(request, msg)
+    return False

openstack_dashboard/dashboards/admin/networks/views.py

@@ -23,6 +23,8 @@ from horizon import tabs
 from horizon.utils import memoized
 
 from openstack_dashboard import api
+from openstack_dashboard.dashboards.admin.networks \
+    import utils as admin_utils
 from openstack_dashboard.dashboards.project.networks.tabs import OverviewTab
 from openstack_dashboard.dashboards.project.networks import views as user_views
 from openstack_dashboard.utils import filters
@@ -66,14 +68,12 @@ class IndexView(tables.PagedTableMixin, tables.DataTableView):
         data = _("Unknown")
 
         try:
-            if api.neutron.is_extension_supported(self.request,
-                                                  'dhcp_agent_scheduler'):
-                # This method is called for each network. If agent-list cannot
-                # be retrieved, we will see many pop-ups. So the error message
-                # will be popup-ed in get_data() below.
-                agents = api.neutron.list_dhcp_agent_hosting_networks(
-                    self.request, network)
-                data = len(agents)
+            # This method is called for each network. If agent-list cannot
+            # be retrieved, we will see many pop-ups. So the error message
+            # will be popup-ed in get_data() below.
+            agents = api.neutron.list_dhcp_agent_hosting_networks(
+                self.request, network)
+            data = len(agents)
         except Exception:
             msg = _('Unable to list dhcp agents hosting network.')
             exceptions.handle(self.request, msg)
@@ -83,6 +83,7 @@ class IndexView(tables.PagedTableMixin, tables.DataTableView):
         return getattr(self, "_needs_filter_first", False)
 
     def get_data(self):
+        networks = None
         try:
             marker, sort_dir = self._get_marker()
 
@@ -120,7 +121,10 @@ class IndexView(tables.PagedTableMixin, tables.DataTableView):
             networks = []
             msg = _('Network list can not be retrieved.')
             exceptions.handle(self.request, msg)
-        if networks:
+        show_agents_column = setting_utils.get_dict_config(
+            'OPENSTACK_NEUTRON_NETWORK', 'show_agents_column')
+        if (networks and show_agents_column and
+                admin_utils.is_dhcp_agent_scheduler_supported(self.request)):
             self.exception = False
             tenant_dict = self._get_tenant_list()
             for n in networks:

openstack_dashboard/defaults.py

@@ -457,6 +457,10 @@ OPENSTACK_NEUTRON_NETWORK = {
     # list, the field will be a regular input field.
     # e.g. ['default', 'test']
     'physical_networks': [],
+
+    # Show the column with the count of dhcp agents in the admin network view.
+    # Disable this on large deployments to avoid slowing down of this view.
+    'show_agents_column': True,
 }
 
 # This settings controls whether IP addresses of servers are retrieved from

releasenotes/notes/add-show_agents_column-setting-to-OPENSTACK_NEUTRON_NETWORK-c1c8e76c61c3d7f0.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Add a new setting to the OPENSTACK_NEUTRON_NETWORK configuration, named
+    show_agents_column, that controls whether the DHCP Agents column should
+    be displayed in the network views. Disabling this may speed up display
+    on large deployments.