Prioritize external network named public

python-tempestconf will prioritize the external network named public
when auto-discovering an external network for tempest.

The public network is the network we end up using in most of the
cases. This will help avoid potential conflicts with other available
external networks that are not meant to be used by tempest. If no
external network with name public is found, the network discovered
last will be used.

Change-Id: Ib10cae1fa3610c4ea0a54b7f4ebbdb146bf4fce2

config_tempest/services/network.py

@@ -65,20 +65,29 @@ class NetworkService(VersionedService):
                              ''.format(self._public_network_id))
 
     def _discover_network(self):
-        LOG.info("No network supplied, trying auto discover for network")
+        LOG.info("No network supplied, trying auto discover for an external "
+                 "network while prioritizing the one called public, if not "
+                 "found, the network discovered last will be used.")
         network_list = self.client.list_networks()
+
         for network in network_list['networks']:
             if network['router:external'] and network['subnets']:
-                LOG.info("Found network, using: %s", network['id'])
+                if network['status'] != 'ACTIVE':
+                    continue
                 self._public_network_id = network['id']
                 self._public_network_name = network['name']
-                break
-
+                # usually the external network we use is called 'public'
+                if network['name'] == 'public':
+                    # we found a network called public, end the loop
+                    break
         # Couldn't find an existing external network
-        else:
+        if not self._public_network_name:
             LOG.error("No external networks found. "
                       "Please note that any test that relies on external "
                       "connectivity would most likely fail.")
+            return
+        LOG.info("Setting %s as the public network for tempest",
+                 self._public_network_id)
 
     @staticmethod
     def get_service_type():

config_tempest/tests/services/test_network.py

@@ -35,6 +35,18 @@ class TestNetworkService(BaseServiceTest):
             'label': 'my_fake_label',
             'name': 'tempest-network',
             'admin_state_up': True,
+        }, {
+            'provider:physical_network': None,
+            'id': 'c034f7f8-b860-4ffd',
+            'router:external': True,
+            'availability_zone_hints': [],
+            'availability_zones': [],
+            'ipv4_address_scope': None,
+            'status': 'ACTIVE',
+            'subnets': ['fake_subnet 2'],
+            'label': 'public_fake_label',
+            'name': 'public',
+            'admin_state_up': True,
         }]
     }
 
@@ -70,15 +82,18 @@ class TestNetworkService(BaseServiceTest):
         return_mock = mock.Mock(return_value=self.FAKE_NETWORK_LIST)
         self.Service.client.list_networks = return_mock
         self.Service._discover_network()
-        self.assertEqual(self.Service._public_network_id, '1ea533d7-4c65-4f25')
-        self.assertEqual(self.Service._public_network_name, 'tempest-network')
+        self.assertEqual(self.Service._public_network_id,
+                         'c034f7f8-b860-4ffd')
+        self.assertEqual(self.Service._public_network_name, 'public')
 
     @mock.patch('config_tempest.services.network.LOG')
     def test_create_network_auto_discover_not_found(self, mock_logging):
-        # delete subnets => network will not be found
+        # delete subnets, set DOWN status => networks will not be found
         self.FAKE_NETWORK_LIST['networks'][0]['subnets'] = []
+        self.FAKE_NETWORK_LIST['networks'][1]['status'] = 'DOWN'
         return_mock = mock.Mock(return_value=self.FAKE_NETWORK_LIST)
         self.Service.client.list_networks = return_mock
+        self.Service._public_network_name = None
         self.Service._discover_network()
         # check if LOG.error was called
         self.assertTrue(mock_logging.error.called)

releasenotes/notes/prioritize-external-network-named-public-fe84c304e536177e.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    python-tempestconf will prioritize the external network named public when
+    auto-discovering an external network for tempest. The public network is
+    the network we end up using in most of the cases. This will help avoid
+    potential conflicts with other available external networks that are not
+    meant to be used by tempest. If no external network with name public is
+    found, the network discovered last will be used.