Workflow variables: modifying engine so that variables work

Implements blueprint mistral-workflow-variables

Change-Id: I92a64526ea70d2c6b8674b12d4cc6d4a5c101151

mistral/engine/default_engine.py

@@ -439,6 +439,7 @@ class DefaultEngine(base.Engine):
         data_flow.add_openstack_data_to_context(wf_ex.context)
         data_flow.add_execution_to_context(wf_ex, wf_ex.context)
         data_flow.add_environment_to_context(wf_ex, wf_ex.context)
+        data_flow.add_workflow_variables_to_context(wf_spec, wf_ex.context)
 
         return wf_ex
 

mistral/tests/unit/engine/test_workflow_variables.py

@@ -0,0 +1,84 @@
+# Copyright 2015 - Mirantis, Inc.
+#
+# 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.
+
+from oslo_config import cfg
+from oslo_log import log as logging
+
+from mistral.db.v2 import api as db_api
+from mistral.services import workflows as wf_service
+from mistral.tests.unit.engine import base
+from mistral.workflow import states
+
+
+LOG = logging.getLogger(__name__)
+
+# Use the set_default method to set value otherwise in certain test cases
+# the change in value is not permanent.
+cfg.CONF.set_default('auth_enable', False, group='pecan')
+
+
+class WorkflowVariablesTest(base.EngineTestCase):
+    def test_workflow_variables(self):
+        wf_text = """---
+        version: '2.0'
+
+        wf:
+          input:
+            - param1: "Hello"
+            - param2
+
+          vars:
+            literal_var: "Literal value"
+            yaql_var: "<% $.param1 %> <% $.param2 %>"
+
+          output:
+            literal_var: <% $.literal_var %>
+            yaql_var: <% $.yaql_var %>
+
+          tasks:
+            task1:
+              action: std.noop
+        """
+
+        wf_service.create_workflows(wf_text)
+
+        # Start workflow.
+        wf_ex = self.engine.start_workflow('wf', {'param2': 'Renat'})
+
+        self._await(lambda: self.is_execution_success(wf_ex.id))
+
+        # Note: We need to reread execution to access related tasks.
+        wf_ex = db_api.get_workflow_execution(wf_ex.id)
+
+        tasks = wf_ex.task_executions
+
+        task1 = self._assert_single_item(tasks, name='task1')
+
+        self.assertEqual(states.SUCCESS, task1.state)
+
+        self._assert_dict_contains_subset(
+            {
+                'literal_var': 'Literal value',
+                'yaql_var': 'Hello Renat'
+            },
+            task1.in_context
+        )
+
+        self.assertDictEqual(
+            {
+                'literal_var': 'Literal value',
+                'yaql_var': 'Hello Renat'
+            },
+            wf_ex.output
+        )

mistral/workflow/data_flow.py

@@ -267,6 +267,16 @@ def add_environment_to_context(wf_ex, context):
     return context
 
 
+def add_workflow_variables_to_context(wf_spec, context):
+    if context is None:
+        context = {}
+
+    return utils.merge_dicts(
+        context,
+        expr.evaluate_recursively(wf_spec.get_vars(), context)
+    )
+
+
 # TODO(rakhmerov): Think how to get rid of this method. It should not be
 # exposed in API.
 def extract_task_result_proxies_to_context(ctx):