Implement pre-delete hook

Add a hook running before resource deletion.

blueprint pre-delete-hook

Depends-On: Ia362650261b0b6c03ce431cbcf292a1685b59883
Change-Id: I8f57cab5ea9ff54d84195add1ba5065520e83489

5 files changed, 94 insertions, 7 deletions

diff --git a/heat/engine/environment.py b/heat/engine/environment.py
index ada4a16a1..e99529dda 100644
--- a/heat/engine/environment.py
+++ b/heat/engine/environment.py
@@ -35,7 +35,11 @@ from heat.engine import support
 LOG = log.getLogger(__name__)
 
 
-HOOK_TYPES = (HOOK_PRE_CREATE, HOOK_PRE_UPDATE) = ('pre-create', 'pre-update')
+HOOK_TYPES = (
+    HOOK_PRE_CREATE, HOOK_PRE_UPDATE, HOOK_PRE_DELETE
+) = (
+    'pre-create', 'pre-update', 'pre-delete'
+)
 
 
 def valid_hook_type(hook):
diff --git a/heat/engine/resource.py b/heat/engine/resource.py
index 9f9dc26be..1b9bf5613 100644
--- a/heat/engine/resource.py
+++ b/heat/engine/resource.py
@@ -1250,6 +1250,13 @@ class Resource(object):
 
         initial_state = self.state
 
+        # This method can be called when we replace a resource, too. In that
+        # case, a hook has already been dealt with in `Resource.update` so we
+        # shouldn't do it here again:
+        if self.stack.action == self.stack.DELETE:
+            yield self._break_if_required(
+                self.DELETE, environment.HOOK_PRE_DELETE)
+
         LOG.info(_LI('deleting %s'), six.text_type(self))
 
         if self._stored_properties_data is not None:
diff --git a/heat/tests/test_environment.py b/heat/tests/test_environment.py
index fab3aab4b..24c8b5a1a 100644
--- a/heat/tests/test_environment.py
+++ b/heat/tests/test_environment.py
@@ -735,7 +735,8 @@ class ResourceRegistryTest(common.HeatTestCase):
 
         registry = environment.ResourceRegistry(None, {})
         msg = ('Invalid hook type "invalid-type" for resource breakpoint, '
-               'acceptable hook types are: (\'pre-create\', \'pre-update\')')
+               'acceptable hook types are: (\'pre-create\', \'pre-update\', '
+               '\'pre-delete\')')
         ex = self.assertRaises(exception.InvalidBreakPointHook,
                                registry.load, {'resources': resources})
         self.assertEqual(msg, six.text_type(ex))
@@ -880,8 +881,11 @@ class HookMatchTest(common.HeatTestCase):
             u'pre_update': {
                 u'hooks': 'pre-update',
             },
-            u'both': {
-                u'hooks': ['pre-create', 'pre-update'],
+            u'pre_delete': {
+                u'hooks': 'pre-delete',
+            },
+            u'all': {
+                u'hooks': ['pre-create', 'pre-update', 'pre-delete'],
             },
         }
         registry = environment.ResourceRegistry(None, {})
@@ -891,13 +895,26 @@ class HookMatchTest(common.HeatTestCase):
             'pre_create', environment.HOOK_PRE_CREATE))
         self.assertFalse(registry.matches_hook(
             'pre_create', environment.HOOK_PRE_UPDATE))
+        self.assertFalse(registry.matches_hook(
+            'pre_create', environment.HOOK_PRE_DELETE))
 
         self.assertTrue(registry.matches_hook(
             'pre_update', environment.HOOK_PRE_UPDATE))
         self.assertFalse(registry.matches_hook(
             'pre_update', environment.HOOK_PRE_CREATE))
+        self.assertFalse(registry.matches_hook(
+            'pre_update', environment.HOOK_PRE_DELETE))
 
         self.assertTrue(registry.matches_hook(
-            'both', environment.HOOK_PRE_CREATE))
+            'pre_delete', environment.HOOK_PRE_DELETE))
+        self.assertFalse(registry.matches_hook(
+            'pre_delete', environment.HOOK_PRE_CREATE))
+        self.assertFalse(registry.matches_hook(
+            'pre_delete', environment.HOOK_PRE_UPDATE))
+
+        self.assertTrue(registry.matches_hook(
+            'all', environment.HOOK_PRE_CREATE))
+        self.assertTrue(registry.matches_hook(
+            'all', environment.HOOK_PRE_UPDATE))
         self.assertTrue(registry.matches_hook(
-            'both', environment.HOOK_PRE_UPDATE))
+            'all', environment.HOOK_PRE_DELETE))
diff --git a/heat/tests/test_resource.py b/heat/tests/test_resource.py
index a2892414f..bef3b26ce 100644
--- a/heat/tests/test_resource.py
+++ b/heat/tests/test_resource.py
@@ -2810,6 +2810,11 @@ class ResourceHookTest(common.HeatTestCase):
         self.assertFalse(res.has_hook('pre-create'))
         self.assertTrue(res.has_hook('pre-update'))
 
+        res.data = mock.Mock(return_value={'pre-delete': 'True'})
+        self.assertFalse(res.has_hook('pre-create'))
+        self.assertFalse(res.has_hook('pre-update'))
+        self.assertTrue(res.has_hook('pre-delete'))
+
     def test_set_hook(self):
         snippet = rsrc_defn.ResourceDefinition('res',
                                                'GenericResourceType')
@@ -2856,7 +2861,7 @@ class ResourceHookTest(common.HeatTestCase):
         self.assertRaises(exception.InvalidBreakPointHook,
                           res.signal, {'unset_hook': 'pre-create'})
 
-    def test_hook_call(self):
+    def test_pre_create_hook_call(self):
         self.stack.env.registry.load(
             {'resources': {'res': {'hooks': 'pre-create'}}})
         snippet = rsrc_defn.ResourceDefinition('res',
@@ -2871,6 +2876,23 @@ class ResourceHookTest(common.HeatTestCase):
         task.run_to_completion()
         self.assertEqual((res.CREATE, res.COMPLETE), res.state)
 
+    def test_pre_delete_hook_call(self):
+        self.stack.env.registry.load(
+            {'resources': {'res': {'hooks': 'pre-delete'}}})
+        snippet = rsrc_defn.ResourceDefinition('res',
+                                               'GenericResourceType')
+        res = resource.Resource('res', snippet, self.stack)
+        res.id = '1234'
+        res.action = 'CREATE'
+        self.stack.action = 'DELETE'
+        task = scheduler.TaskRunner(res.delete)
+        task.start()
+        task.step()
+        self.assertTrue(res.has_hook('pre-delete'))
+        res.clear_hook('pre-delete')
+        task.run_to_completion()
+        self.assertEqual((res.DELETE, res.COMPLETE), res.state)
+
 
 class ResourceAvailabilityTest(common.HeatTestCase):
     def _mock_client_plugin(self, service_types=[], is_available=True):
diff --git a/heat/tests/test_stack_update.py b/heat/tests/test_stack_update.py
index 4499212aa..f137107d8 100644
--- a/heat/tests/test_stack_update.py
+++ b/heat/tests/test_stack_update.py
@@ -404,6 +404,43 @@ class StackUpdateTest(common.HeatTestCase):
                          self.stack.state)
         self.assertEqual('xyz', self.stack['AResource'].properties['Foo'])
 
+    def test_update_replace_delete_hook(self):
+        tmpl = {
+            'HeatTemplateFormatVersion': '2012-12-12',
+            'Parameters': {
+                'foo': {'Type': 'String'}
+            },
+            'Resources': {
+                'AResource': {
+                    'Type': 'ResourceWithPropsType',
+                    'Properties': {'Foo': {'Ref': 'foo'}}
+                }
+            }
+        }
+
+        env = environment.Environment({'foo': 'abc'})
+        env.registry.load(
+            {'resources': {'AResource': {'hooks': 'pre-delete'}}})
+        self.stack = stack.Stack(
+            self.ctx, 'update_test_stack',
+            template.Template(tmpl, env=env))
+        self.stack.store()
+        self.stack.create()
+        self.assertEqual((stack.Stack.CREATE, stack.Stack.COMPLETE),
+                         self.stack.state)
+
+        env2 = environment.Environment({'foo': 'xyz'})
+        env2.registry.load(
+            {'resources': {'AResource': {'hooks': 'pre-delete'}}})
+        updated_stack = stack.Stack(self.ctx, 'updated_stack',
+                                    template.Template(tmpl, env=env2))
+
+        self.stack.update(updated_stack)
+        # The hook is not called, and update succeeds properly
+        self.assertEqual((stack.Stack.UPDATE, stack.Stack.COMPLETE),
+                         self.stack.state)
+        self.assertEqual('xyz', self.stack['AResource'].properties['Foo'])
+
     def test_update_modify_update_failed(self):
         tmpl = {'HeatTemplateFormatVersion': '2012-12-12',
                 'Resources': {'AResource': {'Type': 'ResourceWithPropsType',