Add NovaConfigClient to read nova.conf

Adds a client that can read nova.conf files from the deployment and
return config values.

Change-Id: Ib7d8f92b0dc54c42e22654ac5e811c52afb30c3c

whitebox_tempest_plugin/services/clients.py

@@ -13,6 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import six.moves.configparser as configparser
+from six import StringIO
+
 from oslo_log import log as logging
 from tempest import config
 from tempest.lib.common import ssh
@@ -57,3 +60,17 @@ class VirshXMLClient(SSHClient):
     def capabilities(self):
         command = sudo(in_container('nova_libvirt', 'virsh capabilities'))
         return self.execute(command)
+
+
+class NovaConfigClient(SSHClient):
+    """A client to obtain config values from nova.conf."""
+
+    def _read_nova_conf(self):
+        command = sudo(in_container('nova_libvirt',
+                                    'cat /etc/nova/nova.conf'))
+        return self.execute(command)
+
+    def getopt(self, section, option):
+        config = configparser.ConfigParser()
+        config.readfp(StringIO(self._read_nova_conf()))
+        return config.get(section, option)

whitebox_tempest_plugin/tests/test_clients.py

@@ -0,0 +1,32 @@
+# Copyright 2018 Red Hat
+#
+#    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.
+
+import mock
+import textwrap
+
+from whitebox_tempest_plugin.services import clients
+from whitebox_tempest_plugin.tests import base
+
+
+class ConfigClientTestCase(base.WhiteboxPluginTestCase):
+
+    def test_getopt(self):
+        config_client = clients.NovaConfigClient('fake-host')
+        fake_config = textwrap.dedent("""
+            [default]
+            fake-key = fake-value""").strip()
+        with mock.patch.object(config_client, '_read_nova_conf',
+                               return_value=fake_config):
+            self.assertEqual(config_client.getopt('default', 'fake-key'),
+                             'fake-value')