Fix getting action_spec in create tasks

* In https://review.openstack.org/#/c/96708 we miss the
   moment when we see action_spec in namespace of our
   workbook. Actions of predefined namespaces (e.g
   std) is not a part of workbook namespaces and they
   aren't seen in it.

Change-Id: Ifa2eb391b4a747ec1ec3dceb22a0a29ae1d781c1

mistral/tests/resources/control_flow/one_std_task.yaml

@@ -0,0 +1,17 @@
+Namespaces:
+  Nova:
+    actions:
+      create-vm:
+        class: std.http
+        base-parameters:
+          url: http://path_to_nova/url_for_create
+        output:
+          vm_id: $.base_output.server_id
+
+Workflow:
+  tasks:
+    std_http_task:
+      action: std.http
+      parameters:
+        method: GET
+        url: http://some_url

mistral/tests/unit/engine/default/test_engine.py

@@ -278,3 +278,21 @@ class TestEngine(base.EngineTestCase):
         self.assertEqual(1, len(tasks))
         self.assertEqual(tasks[0]['state'], states.SUCCESS)
         self.assertEqual(execution['state'], states.SUCCESS)
+
+    @mock.patch.object(
+        db_api, 'workbook_get',
+        mock.MagicMock(return_value={'definition': base.get_resource(
+            'control_flow/one_std_task.yaml')}))
+    @mock.patch.object(
+        concrete_engine.DefaultEngine, '_run_tasks',
+        mock.MagicMock(side_effect=base.EngineTestCase.mock_run_tasks))
+    def test_engine_task_std_action_with_namespaces(self):
+        execution = self.engine.start_workflow_execution(WB_NAME,
+                                                         "std_http_task", {})
+
+        tasks = db_api.tasks_get(WB_NAME, execution['id'])
+        execution = db_api.execution_get(WB_NAME, execution['id'])
+
+        self.assertEqual(1, len(tasks))
+        self.assertEqual(states.SUCCESS, tasks[0]['state'])
+        self.assertEqual(states.SUCCESS, execution['state'])

mistral/workbook/workbook.py

@@ -56,8 +56,8 @@ class WorkbookSpec(base.BaseSpec):
         ns_name = full_action_name.split('.')[0]
         action_name = full_action_name.split('.')[1]
 
-        if self.namespaces:
-            return self.namespaces.get(ns_name).actions.get(action_name)
+        if ns_name in self.namespaces:
+            return self.namespaces[ns_name].actions.get(action_name)
 
     def get_actions(self, namespace_name):
         return self.namespaces.get(namespace_name).actions