Optionally include the output when retrieving all executions

During the table refactor, the output was removed from the result
of listing all the executions. This change restores that
behaviour but doesn't include the output by default to avoid
performance problems. To include it, the query param
include_output should be used. For example:

    /v2/executions?include_output=true

Closes-Bug: #1617351
Change-Id: I2acec34920e397789fc61f184ed69071497ea7d9

mistral/api/controllers/v2/execution.py

@@ -47,6 +47,14 @@ STATE_TYPES = wtypes.Enum(
 )
 
 
+def _get_execution_resource(ex):
+    # We need to refer to this lazy-load field explicitly in
+    # order to make sure that it is correctly loaded.
+    hasattr(ex, 'output')
+
+    return resources.Execution.from_dict(ex.to_dict())
+
+
 # TODO(rakhmerov): Make sure to make all needed renaming on public API.
 
 
@@ -218,12 +226,13 @@ class ExecutionsController(rest.RestController):
                          types.uniquelist, types.list, types.uniquelist,
                          wtypes.text, types.uuid, wtypes.text, types.jsontype,
                          types.uuid, STATE_TYPES, wtypes.text, types.jsontype,
-                         types.jsontype, wtypes.text, wtypes.text)
+                         types.jsontype, wtypes.text, wtypes.text, bool)
     def get_all(self, marker=None, limit=None, sort_keys='created_at',
                 sort_dirs='asc', fields='', workflow_name=None,
                 workflow_id=None, description=None, params=None,
                 task_execution_id=None, state=None, state_info=None,
-                input=None, output=None, created_at=None, updated_at=None):
+                input=None, output=None, created_at=None, updated_at=None,
+                include_output=None):
         """Return all Executions.
 
         :param marker: Optional. Pagination marker for large data sets.
@@ -258,6 +267,8 @@ class ExecutionsController(rest.RestController):
                            time and date.
         :param updated_at: Optional. Keep only resources with specific latest
                            update time and date.
+        :param include_output: Optional. Include the output for all executions
+                               in the list
         """
         acl.enforce('executions:list', context.ctx())
 
@@ -281,11 +292,17 @@ class ExecutionsController(rest.RestController):
             filters
         )
 
+        if include_output:
+            resource_function = _get_execution_resource
+        else:
+            resource_function = None
+
         return rest_utils.get_all(
             resources.Executions,
             resources.Execution,
             db_api.get_workflow_executions,
             db_api.get_workflow_execution,
+            resource_function=resource_function,
             marker=marker,
             limit=limit,
             sort_keys=sort_keys,

mistral/tests/unit/api/v2/test_executions.py

@@ -25,6 +25,7 @@ import oslo_messaging
 import uuid
 from webtest import app as webtest_app
 
+from mistral.api.controllers.v2 import execution
 from mistral.db.v2 import api as db_api
 from mistral.db.v2.sqlalchemy import api as sql_db_api
 from mistral.db.v2.sqlalchemy import models
@@ -32,6 +33,7 @@ from mistral.engine.rpc_backend import rpc
 from mistral import exceptions as exc
 from mistral.tests.unit.api import base
 from mistral import utils
+from mistral.utils import rest_utils
 from mistral.workflow import states
 
 # This line is needed for correct initialization of messaging config.
@@ -604,3 +606,27 @@ class TestExecutionsController(base.APITest):
             SUB_WF_EX_JSON_WITH_DESC,
             resp.json['executions'][0]
         )
+
+    @mock.patch.object(db_api, 'get_workflow_executions', MOCK_WF_EXECUTIONS)
+    @mock.patch.object(rest_utils, 'get_all')
+    def test_get_all_executions_with_output(self, mock_get_all):
+        resp = self.app.get('/v2/executions?include_output=true')
+
+        self.assertEqual(200, resp.status_int)
+
+        args, kwargs = mock_get_all.call_args
+        resource_function = kwargs['resource_function']
+
+        self.assertEqual(execution._get_execution_resource, resource_function)
+
+    @mock.patch.object(db_api, 'get_workflow_executions', MOCK_WF_EXECUTIONS)
+    @mock.patch.object(rest_utils, 'get_all')
+    def test_get_all_executions_without_output(self, mock_get_all):
+        resp = self.app.get('/v2/executions')
+
+        self.assertEqual(200, resp.status_int)
+
+        args, kwargs = mock_get_all.call_args
+        resource_function = kwargs['resource_function']
+
+        self.assertEqual(None, resource_function)