From afeaec8f43c30fa06a47c19e6c926309f930a1a6 Mon Sep 17 00:00:00 2001
From: Olga Kopylova <olkonami@gmail.com>
Date: Wed, 1 Apr 2015 15:27:29 +0300
Subject: [PATCH] Lazy import of keystoneclient in osclients

* Move import from keystoneclient to create_keystone_client method
in osclients. This is done to avoid loading keystoneclient on Rally
start to make it starts faster.
* Move import of exceptions from keystoneclient to verified_keystone
method.
* Add unit tests for function create_keystone_client

Implements: blueprint lazy-imports

Change-Id: Ie11618b380a9a51c5b6e237179b4da8b7178d16b
---
 rally/osclients.py           |  8 +++---
 tests/unit/test_osclients.py | 50 ++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/rally/osclients.py b/rally/osclients.py
index 76956182d0..610af32061 100644
--- a/rally/osclients.py
+++ b/rally/osclients.py
@@ -15,10 +15,6 @@
 
 import os
 
-from keystoneclient import discover as keystone_discover
-from keystoneclient import exceptions as keystone_exceptions
-from keystoneclient.v2_0 import client as keystone_v2
-from keystoneclient.v3 import client as keystone_v3
 from oslo_config import cfg
 
 from rally.common.i18n import _
@@ -58,12 +54,15 @@ def cached(func):
 
 
 def create_keystone_client(args):
+    from keystoneclient import discover as keystone_discover
     discover = keystone_discover.Discover(**args)
     for version_data in discover.version_data():
         version = version_data["version"]
         if version[0] <= 2:
+            from keystoneclient.v2_0 import client as keystone_v2
             return keystone_v2.Client(**args)
         elif version[0] == 3:
+            from keystoneclient.v3 import client as keystone_v3
             return keystone_v3.Client(**args)
     raise exceptions.RallyException(
         "Failed to discover keystone version for url %(auth_url)s.", **args)
@@ -110,6 +109,7 @@ class Clients(object):
 
         :returns: Keystone Client
         """
+        from keystoneclient import exceptions as keystone_exceptions
         try:
             # Ensure that user is admin
             client = self.keystone()
diff --git a/tests/unit/test_osclients.py b/tests/unit/test_osclients.py
index 3b52d3cb89..69ef324aaf 100644
--- a/tests/unit/test_osclients.py
+++ b/tests/unit/test_osclients.py
@@ -26,6 +26,56 @@ from tests.unit import fakes
 from tests.unit import test
 
 
+class TestCreateKeystoneClient(test.TestCase):
+
+    def setUp(self):
+        super(TestCreateKeystoneClient, self).setUp()
+        self.kwargs = {"auth_url": "http://auth_url", "username": "user",
+                       "password": "password", "tenant_name": "tenant"}
+
+    def test_create_keystone_client_v2(self):
+        mock_keystone = mock.MagicMock()
+        fake_keystoneclient = mock.MagicMock()
+        mock_keystone.v2_0.client.Client.return_value = fake_keystoneclient
+        mock_discover = mock.MagicMock(
+            version_data=mock.MagicMock(return_value=[{"version": [2]}]))
+        mock_keystone.discover.Discover.return_value = mock_discover
+        with mock.patch.dict("sys.modules",
+                             {"keystoneclient": mock_keystone,
+                              "keystoneclient.v2_0": mock_keystone.v2_0}):
+            client = osclients.create_keystone_client(self.kwargs)
+            mock_discover.version_data.assert_called_once_with()
+            self.assertEqual(fake_keystoneclient, client)
+            mock_keystone.v2_0.client.Client.assert_called_once_with(
+                **self.kwargs)
+
+    def test_create_keystone_client_v3(self):
+        mock_keystone = mock.MagicMock()
+        fake_keystoneclient = mock.MagicMock()
+        mock_keystone.v3.client.Client.return_value = fake_keystoneclient
+        mock_discover = mock.MagicMock(
+            version_data=mock.MagicMock(return_value=[{"version": [3]}]))
+        mock_keystone.discover.Discover.return_value = mock_discover
+        with mock.patch.dict("sys.modules",
+                             {"keystoneclient": mock_keystone,
+                              "keystoneclient.v3": mock_keystone.v3}):
+            client = osclients.create_keystone_client(self.kwargs)
+            mock_discover.version_data.assert_called_once_with()
+            self.assertEqual(fake_keystoneclient, client)
+            mock_keystone.v3.client.Client.assert_called_once_with(
+                **self.kwargs)
+
+    def test_create_keystone_client_version_not_found(self):
+        mock_keystone = mock.MagicMock()
+        mock_discover = mock.MagicMock(
+            version_data=mock.MagicMock(return_value=[{"version": [100500]}]))
+        mock_keystone.discover.Discover.return_value = mock_discover
+        with mock.patch.dict("sys.modules", {"keystoneclient": mock_keystone}):
+            self.assertRaises(exceptions.RallyException,
+                              osclients.create_keystone_client, self.kwargs)
+            mock_discover.version_data.assert_called_once_with()
+
+
 class OSClientsTestCase(test.TestCase):
 
     def setUp(self):