Improve StackValidationFailed exception

We use StackValidationFailed in many different scenarios and
the the message is at times extremely unhelpful, specifically
when the validation error is deep in a nested stack.

Change-Id: I0183bdf81442e62325a427b4eec5c4cd9b7cb91f
Closes-Bug: #1686360

heat/common/exception.py

@@ -227,18 +227,35 @@ class HeatExceptionWithPath(HeatException):
             message=self.error_message
         )
 
-    def error(self):
-        return self.error
-
-    def path(self):
-        return self.path
-
-    def error_message(self):
-        return self.error_message
-
 
 class StackValidationFailed(HeatExceptionWithPath):
-    pass
+    def __init__(self, error=None, path=None, message=None,
+                 resource=None):
+        if path is None:
+            path = []
+        elif isinstance(path, six.string_types):
+            path = [path]
+
+        if resource is not None and not path:
+            path = [resource.stack.t.get_section_name(
+                resource.stack.t.RESOURCES), resource.name]
+        if isinstance(error, Exception):
+            if isinstance(error, StackValidationFailed):
+                str_error = error.error
+                message = error.error_message
+                path = path + error.path
+                # This is a hack to avoid the py3 (chained exception)
+                # json serialization circular reference error from
+                # oslo.messaging.
+                self.args = error.args
+            else:
+                str_error = six.text_type(type(error).__name__)
+                message = six.text_type(error)
+        else:
+            str_error = error
+
+        super(StackValidationFailed, self).__init__(error=str_error, path=path,
+                                                    message=message)
 
 
 class InvalidSchemaError(HeatException):

heat/engine/resources/openstack/heat/resource_chain.py

@@ -98,20 +98,7 @@ class ResourceChain(stack_resource.StackResource):
                 # Valid if it's a template resource
                 pass
 
-        # Check the nested template itself
+        super(ResourceChain, self).validate_nested_stack()
-        nested_tmpl = self.child_template()
-        nested_stack_name = '%s-%s' % (self.stack.name, self.name)
-
-        try:
-            nested_stack = self._parse_nested_stack(nested_stack_name,
-                                                    nested_tmpl,
-                                                    {})
-            nested_stack.strict_validate = False
-            nested_stack.validate()
-        except Exception as ex:
-            msg = (_('Failed to validate nested template: %s')
-                   % six.text_type(ex))
-            raise exception.StackValidationFailed(message=msg)
 
     def handle_create(self):
         return self.create_with_template(self.child_template())

heat/engine/resources/openstack/heat/resource_group.py

@@ -295,8 +295,9 @@ class ResourceGroup(stack_resource.StackResource):
             nested_stack.strict_validate = False
             nested_stack.validate()
         except Exception as ex:
-            msg = _("Failed to validate: %s") % six.text_type(ex)
+            path = "%s<%s>" % (self.name, self.template_url)
-            raise exception.StackValidationFailed(message=msg)
+            raise exception.StackValidationFailed(
+                ex, path=[self.stack.t.RESOURCES, path])
 
     def _current_blacklist(self):
         db_rsrc_names = self.data().get('name_blacklist')

heat/engine/resources/stack_resource.py

@@ -76,10 +76,20 @@ class StackResource(resource.Resource):
         except AssertionError:
             raise
         except Exception as ex:
+            path = "%s<%s>" % (self.name, self.template_url)
             raise exception.StackValidationFailed(
-                error=_("Failed to validate"),
+                ex, path=[self.stack.t.RESOURCES, path])
-                path=[self.stack.t.get_section_name('resources'), self.name],
+
-                message=six.text_type(ex))
+    @property
+    def template_url(self):
+        """Template url for the stack resource.
+
+        When stack resource is a TemplateResource, it's the template
+        location. For group resources like ResourceGroup where the
+        template is constructed dynamically, it's just a placeholder.
+        """
+
+        return "nested_stack"
 
     def _outputs_to_attribs(self, json_snippet):
         outputs = json_snippet.get('Outputs')

heat/engine/resources/template_resource.py

@@ -79,7 +79,7 @@ class TemplateResource(stack_resource.StackResource):
                 'Only Templates with an extension of .yaml or '
                 '.template are supported'))
         else:
-            self.template_name = tri.template_name
+            self._template_name = tri.template_name
             self.resource_type = tri.name
             self.resource_path = tri.path
             if tri.user_resource:
@@ -174,24 +174,28 @@ class TemplateResource(stack_resource.StackResource):
     def child_template(self):
         if not self._parsed_nested:
             self._parsed_nested = template_format.parse(self.template_data(),
-                                                        self.template_name)
+                                                        self.template_url)
         return self._parsed_nested
 
     def regenerate_info_schema(self, definition):
         self._get_resource_info(definition)
         self._generate_schema()
 
+    @property
+    def template_url(self):
+        return self._template_name
+
     def template_data(self):
         # we want to have the latest possible template.
         # 1. look in files
         # 2. try download
         # 3. look in the db
         reported_excp = None
-        t_data = self.stack.t.files.get(self.template_name)
+        t_data = self.stack.t.files.get(self.template_url)
         stored_t_data = t_data
-        if not t_data and self.template_name.endswith((".yaml", ".template")):
+        if not t_data and self.template_url.endswith((".yaml", ".template")):
             try:
-                t_data = self.get_template_file(self.template_name,
+                t_data = self.get_template_file(self.template_url,
                                                 self.allowed_schemes)
             except exception.NotFound as err:
                 if self.action == self.UPDATE:
@@ -204,14 +208,14 @@ class TemplateResource(stack_resource.StackResource):
 
         if t_data is not None:
             if t_data != stored_t_data:
-                self.stack.t.files[self.template_name] = t_data
+                self.stack.t.files[self.template_url] = t_data
             self.stack.t.env.register_class(self.resource_type,
-                                            self.template_name,
+                                            self.template_url,
                                             path=self.resource_path)
             return t_data
         if reported_excp is None:
             reported_excp = ValueError(_('Unknown error retrieving %s') %
-                                       self.template_name)
+                                       self.template_url)
         raise reported_excp
 
     def _validate_against_facade(self, facade_cls):

heat/engine/stack.py

@@ -21,7 +21,6 @@ import warnings
 
 from oslo_config import cfg
 from oslo_log import log as logging
-from oslo_utils import encodeutils
 from oslo_utils import excutils
 from oslo_utils import timeutils as oslo_timeutils
 from oslo_utils import uuidutils
@@ -858,8 +857,8 @@ class Stack(collections.Mapping):
             except Exception as ex:
                 LOG.info("Exception in stack validation",
                          exc_info=True)
-                raise exception.StackValidationFailed(
+                raise exception.StackValidationFailed(error=ex,
-                    message=encodeutils.safe_decode(six.text_type(ex)))
+                                                      resource=res)
             if result:
                 raise exception.StackValidationFailed(message=result)
             eventlet.sleep(0)

heat/tests/openstack/heat/test_resource_chain.py

@@ -146,7 +146,10 @@ class ResourceChainTest(common.HeatTestCase):
             chain.validate_nested_stack()
             self.fail('Exception expected')
         except exception.StackValidationFailed as e:
-            self.assertIn('unknown property group', e.message.lower())
+            self.assertEqual('property error: '
+                             'resources.test<nested_stack>.resources[2].'
+                             'properties: unknown property group',
+                             e.message.lower())
 
     def test_validate_fake_resource_type(self):
         # Setup

heat/tests/test_exception.py

@@ -45,6 +45,17 @@ class TestHeatException(common.HeatTestCase):
 class TestStackValidationFailed(common.HeatTestCase):
 
     scenarios = [
+        ('test_error_as_exception', dict(
+            kwargs=dict(
+                error=exception.StackValidationFailed(
+                    error='Error',
+                    path=['some', 'path'],
+                    message='Some message')),
+            expected='Error: some.path: Some message',
+            called_error='Error',
+            called_path=['some', 'path'],
+            called_msg='Some message'
+        )),
         ('test_full_exception', dict(
             kwargs=dict(
                 error='Error',
@@ -124,8 +135,8 @@ class TestStackValidationFailed(common.HeatTestCase):
         try:
             raise exception.StackValidationFailed(**self.kwargs)
         except exception.StackValidationFailed as ex:
-            self.assertEqual(self.expected, six.text_type(ex))
+            self.assertIn(self.expected, six.text_type(ex))
-            self.assertEqual(self.called_error, ex.error)
+            self.assertIn(self.called_error, ex.error)
             self.assertEqual(self.called_path, ex.path)
             self.assertEqual(self.called_msg, ex.error_message)
 

heat/tests/test_provider_template.py

@@ -579,7 +579,7 @@ class ProviderTemplateTest(common.HeatTestCase):
         temp_res = template_resource.TemplateResource('test_t_res',
                                                       definition, stack)
         self.assertEqual('test_resource.template',
-                         temp_res.template_name)
+                         temp_res.template_url)
 
     def test_resource_info_special(self):
         provider = {
@@ -614,7 +614,7 @@ class ProviderTemplateTest(common.HeatTestCase):
         temp_res = template_resource.TemplateResource('foo',
                                                       definition, stack)
         self.assertEqual('foo.template',
-                         temp_res.template_name)
+                         temp_res.template_url)
 
     def test_get_error_for_invalid_template_name(self):
         # assertion: if the name matches {.yaml|.template} and is valid

heat/tests/test_stack_resource.py

@@ -79,7 +79,7 @@ main_template = '''
 heat_template_version: 2013-05-23
 resources:
   volume_server:
-    type: nested.yaml
+      type: file://tmp/nested.yaml
 '''
 
 my_wrong_nested_template = '''
@@ -396,14 +396,15 @@ class StackResourceTest(StackResourceBaseTest):
     def test_validate_error_reference(self):
         stack_name = 'validate_error_reference'
         tmpl = template_format.parse(main_template)
-        files = {'nested.yaml': my_wrong_nested_template}
+        files = {'file://tmp/nested.yaml': my_wrong_nested_template}
         stack = parser.Stack(utils.dummy_context(), stack_name,
                              templatem.Template(tmpl, files=files))
         rsrc = stack['volume_server']
-        raise_exc_msg = ('Failed to validate: resources.volume_server: '
+        raise_exc_msg = ('InvalidTemplateReference: '
-                         'The specified reference "instance" '
+                         'resources.volume_server<file://tmp/nested.yaml>: '
-                         '(in volume_attachment.Properties.instance_uuid) '
+                         'The specified reference "instance" (in '
-                         'is incorrect.')
+                         'volume_attachment.Properties.instance_uuid) is '
+                         'incorrect.')
         exc = self.assertRaises(exception.StackValidationFailed,
                                 rsrc.validate)
         self.assertEqual(raise_exc_msg, six.text_type(exc))

heat_integrationtests/functional/test_resource_group.py

@@ -82,7 +82,9 @@ resources:
 
         # Prove validation works for non-zero create/update
         template_two_nested = self.template.replace("count: 0", "count: 2")
-        expected_err = "Value 'BAD' is not an integer"
+        expected_err = ("resources.random_group<nested_stack>.resources."
+                        "0<provider.yaml>.resources.random: : "
+                        "Value 'BAD' is not an integer")
         ex = self.assertRaises(exc.HTTPBadRequest, self.update_stack,
                                stack_identifier, template_two_nested,
                                environment=env, files=files)