Check context before returning cached value

The key manager caches the value of barbican client to be reused,
saving an extra call to keystone.  The cached value is only
applicable to the current context, so the context must be checked
before returning the cached value.

Closes-Bug: #1523646

Change-Id: I7cd7f1ba8a749b230c611e4fb20ccf4127354c35

nova/keymgr/barbican.py

@@ -62,6 +62,7 @@ class BarbicanKeyManager(key_mgr.KeyManager):
 
     def __init__(self):
         self._barbican_client = None
+        self._current_context = None
         self._base_url = None
 
     def _get_barbican_client(self, ctxt):
@@ -72,47 +73,56 @@ def _get_barbican_client(self, ctxt):
         :raises Forbidden: if the ctxt is None
         """
 
-        if not self._barbican_client:
-            # Confirm context is provided, if not raise forbidden
-            if not ctxt:
-                msg = _("User is not authorized to use key manager.")
-                LOG.error(msg)
-                raise exception.Forbidden(msg)
-
-            try:
-                _SESSION = session.Session.load_from_conf_options(
-                    CONF,
-                    BARBICAN_OPT_GROUP)
-
-                auth = ctxt.get_auth_plugin()
-                service_type, service_name, interface = (CONF.
-                                                         barbican.
-                                                         catalog_info.
-                                                         split(':'))
-                region_name = CONF.barbican.os_region_name
-                service_parameters = {'service_type': service_type,
-                                      'service_name': service_name,
-                                      'interface': interface,
-                                      'region_name': region_name}
-
-                if CONF.barbican.endpoint_template:
-                    self._base_url = (CONF.barbican.endpoint_template %
-                                      ctxt.to_dict())
-                else:
-                    self._base_url = _SESSION.get_endpoint(
-                        auth, **service_parameters)
-
-                # the barbican endpoint can't have the '/v1' on the end
-                self._barbican_endpoint = self._base_url.rpartition('/')[0]
-
-                sess = session.Session(auth=auth)
-                self._barbican_client = barbican_client.Client(
-                    session=sess,
-                    endpoint=self._barbican_endpoint)
-
-            except Exception as e:
-                with excutils.save_and_reraise_exception():
-                    LOG.error(_LE("Error creating Barbican client: %s"), e)
+        # Confirm context is provided, if not raise forbidden
+        if not ctxt:
+            msg = _("User is not authorized to use key manager.")
+            LOG.error(msg)
+            raise exception.Forbidden(msg)
+
+        if not hasattr(ctxt, 'project_id') or ctxt.project_id is None:
+            msg = _("Unable to create Barbican Client without project_id.")
+            LOG.error(msg)
+            raise exception.KeyManagerError(msg)
+
+        # If same context, return cached barbican client
+        if self._barbican_client and self._current_context == ctxt:
+            return self._barbican_client
+
+        try:
+            _SESSION = session.Session.load_from_conf_options(
+                CONF,
+                BARBICAN_OPT_GROUP)
+
+            auth = ctxt.get_auth_plugin()
+            service_type, service_name, interface = (CONF.
+                                                     barbican.
+                                                     catalog_info.
+                                                     split(':'))
+            region_name = CONF.barbican.os_region_name
+            service_parameters = {'service_type': service_type,
+                                  'service_name': service_name,
+                                  'interface': interface,
+                                  'region_name': region_name}
+
+            if CONF.barbican.endpoint_template:
+                self._base_url = (CONF.barbican.endpoint_template %
+                                  ctxt.to_dict())
+            else:
+                self._base_url = _SESSION.get_endpoint(
+                    auth, **service_parameters)
+
+            # the barbican endpoint can't have the '/v1' on the end
+            self._barbican_endpoint = self._base_url.rpartition('/')[0]
+
+            sess = session.Session(auth=auth)
+            self._barbican_client = barbican_client.Client(
+                session=sess,
+                endpoint=self._barbican_endpoint)
+            self._current_context = ctxt
+
+        except Exception as e:
+            with excutils.save_and_reraise_exception():
+                LOG.error(_LE("Error creating Barbican client: %s"), e)
 
         return self._barbican_client
 

nova/tests/unit/keymgr/test_barbican.py

@@ -37,8 +37,9 @@ def setUp(self):
         super(BarbicanKeyManagerTestCase, self).setUp()
 
         # Create fake auth_token
-        self.ctxt = mock.Mock()
+        self.ctxt = mock.MagicMock()
         self.ctxt.auth_token = "fake_token"
+        self.ctxt.project = "fake_project"
 
         # Create mock barbican client
         self._build_mock_barbican()
@@ -49,6 +50,7 @@ def setUp(self):
         self.pre_hex = "AIDxQp2++uAbKaTVDMXFYIu8PIugJGqkK0JLqkU0rhY="
         self.hex = ("0080f1429dbefae01b29a4d50cc5c5608bbc3c8ba0246aa42b424baa4"
                     "534ae16")
+        self.key_mgr._current_context = self.ctxt
         self.key_mgr._base_url = "http://host:9311/v1"
         self.addCleanup(self._restore)
 
@@ -221,3 +223,51 @@ def test_store_null_context(self):
         self.key_mgr._barbican_client = None
         self.assertRaises(exception.Forbidden,
                           self.key_mgr.store_key, None, None)
+
+    @mock.patch('keystoneclient.session.Session')
+    @mock.patch('barbicanclient.client.Client')
+    def test_get_barbican_client_new(self, mock_barbican, mock_keystone):
+        manager = self._create_key_manager()
+        manager._get_barbican_client(self.ctxt)
+        self.assertEqual(mock_keystone.call_count, 1)
+        self.assertEqual(mock_barbican.call_count, 1)
+
+    @mock.patch('keystoneclient.session.Session')
+    @mock.patch('barbicanclient.client.Client')
+    def test_get_barbican_client_reused(self, mock_barbican, mock_keystone):
+        manager = self._create_key_manager()
+        manager._get_barbican_client(self.ctxt)
+        self.assertEqual(mock_keystone.call_count, 1)
+        self.assertEqual(mock_barbican.call_count, 1)
+        manager._get_barbican_client(self.ctxt)
+        self.assertEqual(mock_keystone.call_count, 1)
+        self.assertEqual(mock_barbican.call_count, 1)
+
+    @mock.patch('keystoneclient.session.Session')
+    @mock.patch('barbicanclient.client.Client')
+    def test_get_barbican_client_not_reused(self, mock_barbican,
+                                            mock_keystone):
+        manager = self._create_key_manager()
+        manager._get_barbican_client(self.ctxt)
+        self.assertEqual(mock_keystone.call_count, 1)
+        self.assertEqual(mock_barbican.call_count, 1)
+        ctxt2 = mock.MagicMock()
+        ctxt2.auth_token = "fake_token2"
+        ctxt2.project = "fake_project2"
+        manager._get_barbican_client(ctxt2)
+        self.assertEqual(mock_keystone.call_count, 2)
+        self.assertEqual(mock_barbican.call_count, 2)
+
+    def test_get_barbican_client_null_context(self):
+        self.assertRaises(exception.Forbidden,
+                          self.key_mgr._get_barbican_client, None)
+
+    def test_get_barbican_client_missing_project(self):
+        del(self.ctxt.project_id)
+        self.assertRaises(exception.KeyManagerError,
+                          self.key_mgr._get_barbican_client, self.ctxt)
+
+    def test_get_barbican_client_none_project(self):
+        self.ctxt.project_id = None
+        self.assertRaises(exception.KeyManagerError,
+                          self.key_mgr._get_barbican_client, self.ctxt)