ConfigDrive: do not use 'id' on a link for the device name

'id' on a link in the openstack spec should be "Generic, generated ID".
current implementation was to use the host's name for the host
side nic.  Which provided names like 'tap-adfasdffd'.

We do not want to name devices like that as its quite unexpected
and non user friendly.  So here we use the system name for any
nic that is present, but then require that the nics found also
be present at the time of rendering.

The end result is that if the system boots with net.ifnames=0
then it will get 'eth0' like names.  and if it boots without net.ifnames
then it will get enp0s1 like names.

1 files changed, 38 insertions, 3 deletions

diff --git a/tests/unittests/test_datasource/test_configdrive.py b/tests/unittests/test_datasource/test_configdrive.py
index 195b8207..1364b39d 100644
--- a/tests/unittests/test_datasource/test_configdrive.py
+++ b/tests/unittests/test_datasource/test_configdrive.py
@@ -73,7 +73,7 @@ NETWORK_DATA = {
          'type': 'ovs', 'mtu': None, 'id': 'tap2f88d109-5b'},
         {'vif_id': '1a5382f8-04c5-4d75-ab98-d666c1ef52cc',
          'ethernet_mac_address': 'fa:16:3e:05:30:fe',
-         'type': 'ovs', 'mtu': None, 'id': 'tap1a5382f8-04'}
+         'type': 'ovs', 'mtu': None, 'id': 'tap1a5382f8-04', 'name': 'nic0'}
     ],
     'networks': [
         {'link': 'tap2ecc7709-b3', 'type': 'ipv4_dhcp',
@@ -88,6 +88,10 @@ NETWORK_DATA = {
     ]
 }
 
+KNOWN_MACS = {
+    'fa:16:3e:69:b0:58': 'enp0s1',
+    'fa:16:3e:d4:57:ad': 'enp0s2'}
+
 CFG_DRIVE_FILES_V2 = {
     'ec2/2009-04-04/meta-data.json': json.dumps(EC2_META),
     'ec2/2009-04-04/user-data': USER_DATA,
@@ -365,10 +369,40 @@ class TestConfigDriveDataSource(TestCase):
         """Verify that network_data is converted and present on ds object."""
         populate_dir(self.tmp, CFG_DRIVE_FILES_V2)
         myds = cfg_ds_from_dir(self.tmp)
-        network_config = ds.convert_network_data(NETWORK_DATA)
+        network_config = ds.convert_network_data(NETWORK_DATA,
+                                                 known_macs=KNOWN_MACS)
         self.assertEqual(myds.network_config, network_config)
 
 
+class TestConvertNetworkData(TestCase):
+    def _getnames_in_config(self, ncfg):
+        return set([n['name'] for n in ncfg['config']
+                    if n['type'] == 'physical'])
+
+    def test_conversion_fills_names(self):
+        ncfg = ds.convert_network_data(NETWORK_DATA, known_macs=KNOWN_MACS)
+        expected = set(['nic0', 'enp0s1', 'enp0s2'])
+        found = self._getnames_in_config(ncfg)
+        self.assertEqual(found, expected)
+
+    @mock.patch('cloudinit.net.get_interfaces_by_mac')
+    def test_convert_reads_system_prefers_name(self, get_interfaces_by_mac):
+        macs = KNOWN_MACS.copy()
+        macs.update({'fa:16:3e:05:30:fe': 'foonic1',
+                     'fa:16:3e:69:b0:58': 'ens1'})
+        get_interfaces_by_mac.return_value = macs
+
+        ncfg = ds.convert_network_data(NETWORK_DATA)
+        expected = set(['nic0', 'ens1', 'enp0s2'])
+        found = self._getnames_in_config(ncfg)
+        self.assertEqual(found, expected)
+
+    def test_convert_raises_value_error_on_missing_name(self):
+        macs = {'aa:aa:aa:aa:aa:00': 'ens1'}
+        self.assertRaises(ValueError, ds.convert_network_data,
+                          NETWORK_DATA, known_macs=macs)
+
+
 def cfg_ds_from_dir(seed_d):
     found = ds.read_config_drive(seed_d)
     cfg_ds = ds.DataSourceConfigDrive(settings.CFG_BUILTIN, None,
@@ -387,7 +421,8 @@ def populate_ds_from_read_config(cfg_ds, source, results):
     cfg_ds.userdata_raw = results.get('userdata')
     cfg_ds.version = results.get('version')
     cfg_ds.network_json = results.get('networkdata')
-    cfg_ds._network_config = ds.convert_network_data(cfg_ds.network_json)
+    cfg_ds._network_config = ds.convert_network_data(
+        cfg_ds.network_json, known_macs=KNOWN_MACS)
 
 
 def populate_dir(seed_dir, files):