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

1 files changed, 51 insertions, 41 deletions

diff --git a/nova/keymgr/barbican.py b/nova/keymgr/barbican.py
index 9f68b1b536..9579ea0623 100644
--- a/nova/keymgr/barbican.py
+++ b/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 @@ class BarbicanKeyManager(key_mgr.KeyManager):
         :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