Merge "Support attributes with dynamic scheme"

heat/engine/attributes.py

@@ -237,6 +237,34 @@ class Attributes(collections.Mapping):
                 '\n\t'.join(six.itervalues(self)))
 
 
+class DynamicSchemeAttributes(Attributes):
+    """The collection of attributes for resources without static attr scheme.
+
+    The class defines collection of attributes for such entities as Resource
+    Group, Software Deployment and so on that doesn't have static attribute
+    scheme. The attribute scheme for such kind of resources can contain
+    attribute from attribute scheme (like other resources) and dynamic
+    attributes (nested stack attrs or API response attrs).
+    """
+
+    def __getitem__(self, key):
+        try:
+            # check if the value can be resolved with attributes
+            # in attributes schema (static attributes)
+            return super(DynamicSchemeAttributes, self).__getitem__(key)
+        except KeyError:
+            # ok, the attribute is not present in attribute scheme
+            # try to check the attributes dynamically
+            if key in self._resolved_values:
+                return self._resolved_values[key]
+
+            value = self._resolver(key)
+            if value is not None:
+                self._resolved_values[key] = value
+
+            return value
+
+
 def select_from_attribute(attribute_value, path):
     '''
     Select an element from an attribute value.

heat/engine/resource.py

@@ -182,6 +182,18 @@ class Resource(object):
 
         return super(Resource, cls).__new__(ResourceClass)
 
+    def _init_attributes(self):
+        """The method that defines attribute initialization for a resource.
+
+        Some resource requires different initialization of resource attributes.
+        So they must override this method and return the initialized
+        attributes to the resource.
+        :return: resource attributes
+        """
+        return attributes.Attributes(self.name,
+                                     self.attributes_schema,
+                                     self._resolve_all_attributes)
+
     def __init__(self, name, definition, stack):
 
         def _validate_name(res_name):
@@ -196,9 +208,7 @@ class Resource(object):
         self.t = definition
         self.reparse()
         self.attributes_schema.update(self.base_attributes_schema)
-        self.attributes = attributes.Attributes(self.name,
-                                                self.attributes_schema,
-                                                self._resolve_all_attributes)
+        self.attributes = self._init_attributes()
 
         self.abandon_in_progress = False
 

heat/tests/common.py

@@ -161,6 +161,8 @@ class HeatTestCase(testscenarios.WithScenarios,
                                  generic_rsrc.StackResourceType)
         resource._register_class('ResourceWithRestoreType',
                                  generic_rsrc.ResourceWithRestoreType)
+        resource._register_class('DynamicSchemaResource',
+                                 generic_rsrc.DynamicSchemaResource)
 
     def patchobject(self, obj, attr, **kwargs):
         mockfixture = self.useFixture(mockpatch.PatchObject(obj, attr,

heat/tests/generic_resource.py

@@ -263,3 +263,27 @@ class ResourceWithRestoreType(ResWithComplexPropsAndAttrs):
         value = data['resource_data']['a_string']
         props['a_string'] = value
         return defn.freeze(properties=props)
+
+
+class DynamicSchemaResource(resource.Resource):
+    """Resource with an attribute not registered in the attribute schema."""
+    properties_schema = {}
+
+    attributes_schema = {
+        'stat_attr': attributes.Schema('A generic static attribute',
+                                       type=attributes.Schema.STRING),
+    }
+
+    def _init_attributes(self):
+        # software deployment scheme is not static
+        # so return dynamic attributes for it
+        return attributes.DynamicSchemeAttributes(
+            self.name, self.attributes_schema, self._resolve_attribute)
+
+    def _resolve_attribute(self, name):
+        if name == 'stat_attr':
+            return "static_attribute"
+        elif name == 'dynamic_attr':
+            return "dynamic_attribute"
+        else:
+            raise KeyError()

heat/tests/test_attributes.py

@@ -16,8 +16,13 @@ import six
 
 from heat.engine import attributes
 from heat.engine import resources
+from heat.engine import rsrc_defn
+from heat.engine import stack
 from heat.engine import support
+from heat.engine import template
 from heat.tests import common
+from heat.tests import generic_resource
+from heat.tests import utils
 
 
 class AttributeSchemaTest(common.HeatTestCase):
@@ -243,3 +248,25 @@ class AttributesTypeTest(common.HeatTestCase):
         self.assertNotIn(msg, self.LOG.output)
         attribs._validate_type(attr, self.invalid_value)
         self.assertIn(msg, self.LOG.output)
+
+
+class DynamicSchemeAttributeTest(common.HeatTestCase):
+    def setUp(self):
+        super(DynamicSchemeAttributeTest, self).setUp()
+        test_stack = stack.Stack(
+            utils.dummy_context(), 'test_stack',
+            template.Template.create_empty_template())
+        snippet = rsrc_defn.ResourceDefinition('test_resource',
+                                               'DynamicSchemaResource')
+        test_res = generic_resource.DynamicSchemaResource(
+            'aresource', snippet, test_stack)
+        self.attrs = test_res.attributes
+
+    def test_get_static_attribute(self):
+        self.assertEqual("static_attribute", self.attrs["stat_attr"])
+
+    def test_get_dynamic_attribute(self):
+        self.assertEqual("dynamic_attribute", self.attrs["dynamic_attr"])
+
+    def test_get_non_existing_attribute(self):
+        self.assertRaises(KeyError, self.attrs.__getitem__, "non_existing")