Azure: if user has set hostname, do not overwrite it

Due to the way the azure boot works, where we identify the hostname to the
fabric, we were inadvertently overwriting hostname that the user had set.

LP: #1375252

2 files changed, 172 insertions, 46 deletions

diff --git a/tests/unittests/test_data.py b/tests/unittests/test_data.py
index 1b15dafa..c603bfdb 100644
--- a/tests/unittests/test_data.py
+++ b/tests/unittests/test_data.py
@@ -511,7 +511,6 @@ c: 4
         mockobj.assert_called_once_with(
             ci.paths.get_ipath("cloud_config"), "", 0o600)
 
-
     def test_cloud_config_archive(self):
         non_decodable = b'\x11\xc9\xb4gTH\xee\x12'
         data = [{'content': '#cloud-config\npassword: gocubs\n'},
diff --git a/tests/unittests/test_datasource/test_azure.py b/tests/unittests/test_datasource/test_azure.py
index 8112c69b..7e789853 100644
--- a/tests/unittests/test_datasource/test_azure.py
+++ b/tests/unittests/test_datasource/test_azure.py
@@ -116,9 +116,6 @@ class TestAzureDataSource(TestCase):
             data['iid_from_shared_cfg'] = path
             return 'i-my-azure-id'
 
-        def _apply_hostname_bounce(**kwargs):
-            data['apply_hostname_bounce'] = kwargs
-
         if data.get('ovfcontent') is not None:
             populate_dir(os.path.join(self.paths.seed_dir, "azure"),
                          {'ovf-env.xml': data['ovfcontent']})
@@ -132,7 +129,9 @@ class TestAzureDataSource(TestCase):
             (mod, 'wait_for_files', _wait_for_files),
             (mod, 'pubkeys_from_crt_files', _pubkeys_from_crt_files),
             (mod, 'iid_from_shared_config', _iid_from_shared_config),
-            (mod, 'apply_hostname_bounce', _apply_hostname_bounce),
+            (mod, 'perform_hostname_bounce', mock.MagicMock()),
+            (mod, 'get_hostname', mock.MagicMock()),
+            (mod, 'set_hostname', mock.MagicMock()),
             ])
 
         dsrc = mod.DataSourceAzureNet(
@@ -272,47 +271,6 @@ class TestAzureDataSource(TestCase):
         for mypk in mypklist:
             self.assertIn(mypk, dsrc.cfg['_pubkeys'])
 
-    def test_disabled_bounce(self):
-        pass
-
-    def test_apply_bounce_call_1(self):
-        # hostname needs to get through to apply_hostname_bounce
-        odata = {'HostName': 'my-random-hostname'}
-        data = {'ovfcontent': construct_valid_ovf_env(data=odata)}
-
-        self._get_ds(data).get_data()
-        self.assertIn('hostname', data['apply_hostname_bounce'])
-        self.assertEqual(data['apply_hostname_bounce']['hostname'],
-                         odata['HostName'])
-
-    def test_apply_bounce_call_configurable(self):
-        # hostname_bounce should be configurable in datasource cfg
-        cfg = {'hostname_bounce': {'interface': 'eth1', 'policy': 'off',
-                                   'command': 'my-bounce-command',
-                                   'hostname_command': 'my-hostname-command'}}
-        odata = {'HostName': "xhost",
-                'dscfg': {'text': b64e(yaml.dump(cfg)),
-                          'encoding': 'base64'}}
-        data = {'ovfcontent': construct_valid_ovf_env(data=odata)}
-        self._get_ds(data).get_data()
-
-        for k in cfg['hostname_bounce']:
-            self.assertIn(k, data['apply_hostname_bounce'])
-
-        for k, v in cfg['hostname_bounce'].items():
-            self.assertEqual(data['apply_hostname_bounce'][k], v)
-
-    def test_set_hostname_disabled(self):
-        # config specifying set_hostname off should not bounce
-        cfg = {'set_hostname': False}
-        odata = {'HostName': "xhost",
-                'dscfg': {'text': b64e(yaml.dump(cfg)),
-                          'encoding': 'base64'}}
-        data = {'ovfcontent': construct_valid_ovf_env(data=odata)}
-        self._get_ds(data).get_data()
-
-        self.assertEqual(data.get('apply_hostname_bounce', "N/A"), "N/A")
-
     def test_default_ephemeral(self):
         # make sure the ephemeral device works
         odata = {}
@@ -425,6 +383,175 @@ class TestAzureDataSource(TestCase):
             load_file(os.path.join(self.waagent_d, 'ovf-env.xml')))
 
 
+class TestAzureBounce(TestCase):
+
+    def mock_out_azure_moving_parts(self):
+        self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'invoke_agent'))
+        self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'wait_for_files'))
+        self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'iid_from_shared_config',
+                              mock.MagicMock(return_value='i-my-azure-id')))
+        self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'list_possible_azure_ds_devs',
+                              mock.MagicMock(return_value=[])))
+        self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'find_ephemeral_disk',
+                              mock.MagicMock(return_value=None)))
+        self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'find_ephemeral_part',
+                              mock.MagicMock(return_value=None)))
+
+    def setUp(self):
+        super(TestAzureBounce, self).setUp()
+        self.tmp = tempfile.mkdtemp()
+        self.waagent_d = os.path.join(self.tmp, 'var', 'lib', 'waagent')
+        self.paths = helpers.Paths({'cloud_dir': self.tmp})
+        self.addCleanup(shutil.rmtree, self.tmp)
+        DataSourceAzure.BUILTIN_DS_CONFIG['data_dir'] = self.waagent_d
+        self.patches = ExitStack()
+        self.mock_out_azure_moving_parts()
+        self.get_hostname = self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'get_hostname'))
+        self.set_hostname = self.patches.enter_context(
+            mock.patch.object(DataSourceAzure, 'set_hostname'))
+        self.subp = self.patches.enter_context(
+            mock.patch('cloudinit.sources.DataSourceAzure.util.subp'))
+
+    def tearDown(self):
+        self.patches.close()
+
+    def _get_ds(self, ovfcontent=None):
+        if ovfcontent is not None:
+            populate_dir(os.path.join(self.paths.seed_dir, "azure"),
+                         {'ovf-env.xml': ovfcontent})
+        return DataSourceAzure.DataSourceAzureNet(
+            {}, distro=None, paths=self.paths)
+
+    def get_ovf_env_with_dscfg(self, hostname, cfg):
+        odata = {
+            'HostName': hostname,
+            'dscfg': {
+                'text': b64e(yaml.dump(cfg)),
+                'encoding': 'base64'
+            }
+        }
+        return construct_valid_ovf_env(data=odata)
+
+    def test_disabled_bounce_does_not_change_hostname(self):
+        cfg = {'hostname_bounce': {'policy': 'off'}}
+        self._get_ds(self.get_ovf_env_with_dscfg('test-host', cfg)).get_data()
+        self.assertEqual(0, self.set_hostname.call_count)
+
+    @mock.patch('cloudinit.sources.DataSourceAzure.perform_hostname_bounce')
+    def test_disabled_bounce_does_not_perform_bounce(
+            self, perform_hostname_bounce):
+        cfg = {'hostname_bounce': {'policy': 'off'}}
+        self._get_ds(self.get_ovf_env_with_dscfg('test-host', cfg)).get_data()
+        self.assertEqual(0, perform_hostname_bounce.call_count)
+
+    def test_same_hostname_does_not_change_hostname(self):
+        host_name = 'unchanged-host-name'
+        self.get_hostname.return_value = host_name
+        cfg = {'hostname_bounce': {'policy': 'yes'}}
+        self._get_ds(self.get_ovf_env_with_dscfg(host_name, cfg)).get_data()
+        self.assertEqual(0, self.set_hostname.call_count)
+
+    @mock.patch('cloudinit.sources.DataSourceAzure.perform_hostname_bounce')
+    def test_unchanged_hostname_does_not_perform_bounce(
+            self, perform_hostname_bounce):
+        host_name = 'unchanged-host-name'
+        self.get_hostname.return_value = host_name
+        cfg = {'hostname_bounce': {'policy': 'yes'}}
+        self._get_ds(self.get_ovf_env_with_dscfg(host_name, cfg)).get_data()
+        self.assertEqual(0, perform_hostname_bounce.call_count)
+
+    @mock.patch('cloudinit.sources.DataSourceAzure.perform_hostname_bounce')
+    def test_force_performs_bounce_regardless(self, perform_hostname_bounce):
+        host_name = 'unchanged-host-name'
+        self.get_hostname.return_value = host_name
+        cfg = {'hostname_bounce': {'policy': 'force'}}
+        self._get_ds(self.get_ovf_env_with_dscfg(host_name, cfg)).get_data()
+        self.assertEqual(1, perform_hostname_bounce.call_count)
+
+    def test_different_hostnames_sets_hostname(self):
+        expected_hostname = 'azure-expected-host-name'
+        self.get_hostname.return_value = 'default-host-name'
+        self._get_ds(
+            self.get_ovf_env_with_dscfg(expected_hostname, {})).get_data()
+        self.assertEqual(expected_hostname,
+                         self.set_hostname.call_args_list[0][0][0])
+
+    @mock.patch('cloudinit.sources.DataSourceAzure.perform_hostname_bounce')
+    def test_different_hostnames_performs_bounce(
+            self, perform_hostname_bounce):
+        expected_hostname = 'azure-expected-host-name'
+        self.get_hostname.return_value = 'default-host-name'
+        self._get_ds(
+            self.get_ovf_env_with_dscfg(expected_hostname, {})).get_data()
+        self.assertEqual(1, perform_hostname_bounce.call_count)
+
+    def test_different_hostnames_sets_hostname_back(self):
+        initial_host_name = 'default-host-name'
+        self.get_hostname.return_value = initial_host_name
+        self._get_ds(
+            self.get_ovf_env_with_dscfg('some-host-name', {})).get_data()
+        self.assertEqual(initial_host_name,
+                         self.set_hostname.call_args_list[-1][0][0])
+
+    @mock.patch('cloudinit.sources.DataSourceAzure.perform_hostname_bounce')
+    def test_failure_in_bounce_still_resets_host_name(
+            self, perform_hostname_bounce):
+        perform_hostname_bounce.side_effect = Exception
+        initial_host_name = 'default-host-name'
+        self.get_hostname.return_value = initial_host_name
+        self._get_ds(
+            self.get_ovf_env_with_dscfg('some-host-name', {})).get_data()
+        self.assertEqual(initial_host_name,
+                         self.set_hostname.call_args_list[-1][0][0])
+
+    def test_environment_correct_for_bounce_command(self):
+        interface = 'int0'
+        hostname = 'my-new-host'
+        old_hostname = 'my-old-host'
+        self.get_hostname.return_value = old_hostname
+        cfg = {'hostname_bounce': {'interface': interface, 'policy': 'force'}}
+        data = self.get_ovf_env_with_dscfg(hostname, cfg)
+        self._get_ds(data).get_data()
+        self.assertEqual(1, self.subp.call_count)
+        bounce_env = self.subp.call_args[1]['env']
+        self.assertEqual(interface, bounce_env['interface'])
+        self.assertEqual(hostname, bounce_env['hostname'])
+        self.assertEqual(old_hostname, bounce_env['old_hostname'])
+
+    def test_default_bounce_command_used_by_default(self):
+        cmd = 'default-bounce-command'
+        DataSourceAzure.BUILTIN_DS_CONFIG['hostname_bounce']['command'] = cmd
+        cfg = {'hostname_bounce': {'policy': 'force'}}
+        data = self.get_ovf_env_with_dscfg('some-hostname', cfg)
+        self._get_ds(data).get_data()
+        self.assertEqual(1, self.subp.call_count)
+        bounce_args = self.subp.call_args[1]['args']
+        self.assertEqual(cmd, bounce_args)
+
+    @mock.patch('cloudinit.sources.DataSourceAzure.perform_hostname_bounce')
+    def test_set_hostname_option_can_disable_bounce(
+            self, perform_hostname_bounce):
+        cfg = {'set_hostname': False, 'hostname_bounce': {'policy': 'force'}}
+        data = self.get_ovf_env_with_dscfg('some-hostname', cfg)
+        self._get_ds(data).get_data()
+
+        self.assertEqual(0, perform_hostname_bounce.call_count)
+
+    def test_set_hostname_option_can_disable_hostname_set(self):
+        cfg = {'set_hostname': False, 'hostname_bounce': {'policy': 'force'}}
+        data = self.get_ovf_env_with_dscfg('some-hostname', cfg)
+        self._get_ds(data).get_data()
+
+        self.assertEqual(0, self.set_hostname.call_count)
+
+
 class TestReadAzureOvf(TestCase):
     def test_invalid_xml_raises_non_azure_ds(self):
         invalid_xml = "<foo>" + construct_valid_ovf_env(data={})