Convergence: Work on IN_PROGRESS resources once lock acquired

The check in resource update logic to raise ResourceFailure if a
resource is already IN_PROGRESS does not apply for convergence.

- In convergence, before acting on a resource we try to acquire lock,
hence if a worker is already working on a resource(IN_PROGRESS),
another worker cannot start working on this IN_PROGRESS resource.
- The scenario a worker would reach the above check is when the lock
was forcibly acquired(lets say its worker died). But in this case
under convergence, even if the resource status is IN_PROGRESS we
need to act on it.

Hence removing the above check for convergence.

Change-Id: Ic17a3aa53a94b9e9ab5c841388d509b1f97103c9

heat/engine/resource.py

@@ -915,11 +915,13 @@ class Resource(object):
                                       prev_resource):
                 return
 
-            if (self.action, self.status) in ((self.CREATE, self.IN_PROGRESS),
-                                              (self.UPDATE, self.IN_PROGRESS),
-                                              (self.ADOPT, self.IN_PROGRESS)):
-                exc = Exception(_('Resource update already requested'))
-                raise exception.ResourceFailure(exc, self, action)
+            if not cfg.CONF.convergence_engine:
+                if (self.action, self.status) in (
+                        (self.CREATE, self.IN_PROGRESS),
+                        (self.UPDATE, self.IN_PROGRESS),
+                        (self.ADOPT, self.IN_PROGRESS)):
+                    exc = Exception(_('Resource update already requested'))
+                    raise exception.ResourceFailure(exc, self, action)
 
             LOG.info(_LI('updating %s'), six.text_type(self))
 

heat/tests/test_resource.py

@@ -375,6 +375,25 @@ class ResourceTest(common.HeatTestCase):
             exception.UpdateReplace, scheduler.TaskRunner(res.update, utmpl))
         self.assertTrue(res.prepare_for_replace.called)
 
+    def test_update_rsrc_in_progress_raises_exception(self):
+        class TestResource(resource.Resource):
+            properties_schema = {'a_string': {'Type': 'String'}}
+            update_allowed_properties = ('a_string',)
+
+        cfg.CONF.set_override('convergence_engine', False)
+        resource._register_class('TestResource', TestResource)
+
+        tmpl = rsrc_defn.ResourceDefinition('test_resource',
+                                            'TestResource')
+        res = TestResource('test_resource', tmpl, self.stack)
+
+        utmpl = rsrc_defn.ResourceDefinition('test_resource', 'TestResource',
+                                             {'a_string': 'foo'})
+        res.action = res.UPDATE
+        res.status = res.IN_PROGRESS
+        self.assertRaises(
+            exception.ResourceFailure, scheduler.TaskRunner(res.update, utmpl))
+
     def test_update_replace_rollback(self):
         class TestResource(resource.Resource):
             properties_schema = {'a_string': {'Type': 'String'}}