Fixed 500 error in get_result API handler

If there is no task in DB with environemnt id and task id passed in
handler, a server error was returned by the API.

This patch fixes this bug.

Closes-Bug: #162206
Change-Id: I9fd84a963a1eacf8ab2aa428cfb4365f80fff02b

murano/api/v1/actions.py

@@ -20,7 +20,7 @@ from murano.db import models
 from murano.db.services import environments as envs
 from murano.db.services import sessions
 from murano.db import session as db_session
-from murano.common.i18n import _LI, _LE
+from murano.common.i18n import _LI, _LE, _
 from murano.openstack.common import log as logging
 from murano.services import actions
 from murano.services import states
@@ -79,7 +79,17 @@ class Controller(object):
 
         unit = db_session.get_session()
         self._validate_environment(unit, request, environment_id)
-        return actions.ActionServices.get_result(environment_id, task_id, unit)
+        result = actions.ActionServices.get_result(environment_id, task_id,
+                                                   unit)
+
+        if result is not None:
+            return result
+        msg = (_('Result for task with environment_id: {} and '
+                 'task_id: {} was not found.')
+               .format(environment_id, task_id))
+
+        LOG.error(msg)
+        raise exc.HTTPNotFound(msg)
 
 
 def create_resource():

murano/services/actions.py

@@ -111,4 +111,8 @@ class ActionServices(object):
     def get_result(environment_id, task_id, unit):
         task = unit.query(models.Task).filter_by(
             id=task_id, environment_id=environment_id).first()
-        return task.result
+
+        if task is not None:
+            return task.result
+
+        return None

murano/tests/unit/api/v1/test_actions.py

@@ -95,3 +95,60 @@ class TestActionsApi(tb.ControllerTest, tb.MuranoApiTestCase):
         self.mock_engine_rpc.handle_task.assert_called_once_with(rpc_task)
 
         self.assertIn('task_id', result)
+
+    def test_get_result(self, _):
+        """Result of task with given id and environment id is returned."""
+        now = timeutils.utcnow()
+        expected_environment_id = 'test_environment'
+        expected_task_id = 'test_task'
+        expected_result = {'test_result': 'test_result'}
+
+        environment = models.Environment(
+            id=expected_environment_id,
+            name='test_environment', created=now, updated=now,
+            tenant_id=self.tenant
+        )
+
+        task = models.Task(
+            id=expected_task_id,
+            started=now,
+            finished=now,
+            result=expected_result,
+            environment_id=expected_environment_id
+        )
+
+        test_utils.save_models(environment, task)
+
+        request = self._get(
+            '/environments/{environment_id}/actions/{task_id}'
+            .format(environment_id=expected_environment_id,
+                    task_id=expected_task_id),
+        )
+
+        response = request.get_response(self.api)
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.json, expected_result)
+
+    def test_get_result_not_found(self, _):
+        """If task does not exists, it should be handled correctly
+        and API should return 404.
+        """
+        expected_environment_id = 'test_environment'
+
+        environment = models.Environment(
+            id=expected_environment_id,
+            name='test_environment',
+            tenant_id=self.tenant
+        )
+        test_utils.save_models(environment)
+
+        request = self._get(
+            '/environments/{environment_id}/actions/{task_id}'
+            .format(environment_id=expected_environment_id,
+                    task_id='not_existent_task_id'),
+        )
+
+        response = request.get_response(self.api)
+
+        self.assertEqual(response.status_code, 404)