From 42de0c9a3cec897161c145c3d0ae8e10e3b19d5b Mon Sep 17 00:00:00 2001 From: Randall Burt Date: Thu, 13 Jun 2013 12:41:50 -0500 Subject: [PATCH] Introduce a schema for attributes Similar to properties, adds attribute_schema and attributes members to Resources in order to facilitate document generation and template provider stubs for resources. Change-Id: I5e207360816fbc685c66db68a7fab8afad11bf10 Implements: blueprint attributes-schema --- heat/engine/attributes.py | 135 +++++++++++++++++++++++++++++++++ heat/engine/resource.py | 26 ++++++- heat/tests/generic_resource.py | 5 ++ heat/tests/test_attributes.py | 110 +++++++++++++++++++++++++++ 4 files changed, 275 insertions(+), 1 deletion(-) create mode 100644 heat/engine/attributes.py create mode 100644 heat/tests/test_attributes.py diff --git a/heat/engine/attributes.py b/heat/engine/attributes.py new file mode 100644 index 0000000000..d5e0811c35 --- /dev/null +++ b/heat/engine/attributes.py @@ -0,0 +1,135 @@ +# vim: tabstop=4 shiftwidth=4 softtabstop=4 + +# +# Licensed under the Apache License, Version 2.0 (the "License"); you may +# not use this file except in compliance with the License. You may obtain +# a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +# License for the specific language governing permissions and limitations +# under the License. + +import collections + + +class Attribute(object): + """ + An attribute description and resolved value. + + :param resource_name: the logical name of the resource having this + attribute + :param attr_name: the name of the attribute + :param description: attribute description + :param resolver: a function that will resolve the value of this attribute + """ + + def __init__(self, attr_name, description, resolver): + self._name = attr_name + self._description = description + self._resolve = resolver + + @property + def name(self): + """ + :returns: The attribute name + """ + return self._name + + @property + def value(self): + """ + :returns: The resolved attribute value + """ + return self._resolve(self._name) + + @property + def description(self): + """ + :returns: A description of the attribute + """ + return self._description + + @staticmethod + def as_output(resource_name, attr_name, description): + """ + :param resource_name: the logical name of a resource + :param attr_name: the name of the attribute + :description: the description of the attribute + :returns: This attribute as a template 'Output' entry + """ + return { + attr_name: { + "Value": '{"Fn::GetAtt": ["%s", "%s"]}' % (resource_name, + attr_name), + "Description": description + } + } + + def __call__(self): + return self.value + + def __str__(self): + return ("Attribute %s: %s" % (self.name, self.value)) + + +class Attributes(collections.Mapping): + """Models a collection of Resource Attributes.""" + + def __init__(self, res_name, schema, resolver): + self._resource_name = res_name + self._attributes = dict((k, Attribute(k, v, resolver)) + for k, v in schema.items()) + + @property + def attributes(self): + """ + Get a copy of the attribute definitions in this collection + (as opposed to attribute values); useful for doc and + template format generation + + :returns: attribute definitions + """ + # return a deep copy to avoid modification + return dict((k, Attribute(k, v.description, v._resolve)) for k, v + in self._attributes.items()) + + @staticmethod + def as_outputs(resource_name, resource_class): + """ + :param resource_name: logical name of the resource + :param resource_class: resource implementation class + :returns: The attributes of the specified resource_class as a template + Output map + """ + outputs = {} + for name, descr in resource_class.attributes_schema.items(): + outputs.update(Attribute.as_output(resource_name, name, descr)) + return outputs + + @staticmethod + def schema_from_outputs(json_snippet): + return dict(("Outputs.%s" % k, v.get("Description")) + for k, v in json_snippet.items()) + + def __getitem__(self, key): + if key not in self: + raise KeyError('%s: Invalid attribute %s' % + (self._resource_name, key)) + return self._attributes[key]() + + def __len__(self): + return len(self._attributes) + + def __contains__(self, key): + return key in self._attributes + + def __iter__(self): + return iter(self._attributes) + + def __repr__(self): + return ("Attributes for %s:\n\t" % self._resource_name + + '\n\t'.join(self._attributes.values())) diff --git a/heat/engine/resource.py b/heat/engine/resource.py index 9cb7cb6252..a77c20ea40 100644 --- a/heat/engine/resource.py +++ b/heat/engine/resource.py @@ -23,6 +23,8 @@ from heat.db import api as db_api from heat.common import identifier from heat.common import short_id from heat.engine import timestamp +# import class to avoid name collisions and ugly aliasing +from heat.engine.attributes import Attributes from heat.engine.properties import Properties from heat.openstack.common import log as logging @@ -122,6 +124,10 @@ class Resource(object): # supported for handle_update, used by update_template_diff_properties update_allowed_properties = () + # Resource implementations set this to the name: description dictionary + # that describes the appropriate resource attributes + attributes_schema = {} + def __new__(cls, name, json, stack): '''Create a new Resource of the appropriate class for its type.''' @@ -149,6 +155,9 @@ class Resource(object): self.t.get('Properties', {}), self.stack.resolve_runtime_data, self.name) + self.attributes = Attributes(self.name, + self.attributes_schema, + self._resolve_attribute) resource = db_api.resource_get_by_name_and_stack(self.context, name, stack.id) @@ -570,6 +579,17 @@ class Resource(object): elif (action, status) == (self.CREATE, self.IN_PROGRESS): self._store() + def _resolve_attribute(self, name): + """ + Default implementation; should be overridden by resources that expose + attributes + + :param name: The attribute to resolve + :returns: the resource attribute named key + """ + # By default, no attributes resolve + pass + def state_set(self, action, status, reason="state changed"): if action not in self.ACTIONS: raise ValueError("Invalid action %s" % action) @@ -604,7 +624,11 @@ class Resource(object): http://docs.amazonwebservices.com/AWSCloudFormation/latest/UserGuide/\ intrinsic-function-reference-getatt.html ''' - return unicode(self.name) + try: + return self.attributes[key] + except KeyError: + raise exception.InvalidTemplateAttribute(resource=self.name, + key=key) def FnBase64(self, data): ''' diff --git a/heat/tests/generic_resource.py b/heat/tests/generic_resource.py index 7cd267c4b5..a6b7dd7735 100644 --- a/heat/tests/generic_resource.py +++ b/heat/tests/generic_resource.py @@ -24,9 +24,14 @@ class GenericResource(resource.Resource): Dummy resource for use in tests ''' properties_schema = {} + attributes_schema = {'foo': 'A generic attribute', + 'Foo': 'Another generic attribute'} def handle_create(self): logger.warning('Creating generic resource (Type "%s")' % self.type()) def handle_update(self, json_snippet, tmpl_diff, prop_diff): logger.warning('Updating generic resource (Type "%s")' % self.type()) + + def _resolve_attribute(self, name): + return self.name diff --git a/heat/tests/test_attributes.py b/heat/tests/test_attributes.py new file mode 100644 index 0000000000..a1e3ca887d --- /dev/null +++ b/heat/tests/test_attributes.py @@ -0,0 +1,110 @@ +# vim: tabstop=4 shiftwidth=4 softtabstop=4 + +# Licensed under the Apache License, Version 2.0 (the "License"); you may +# not use this file except in compliance with the License. You may obtain +# a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +# License for the specific language governing permissions and limitations +# under the License. + +import mox + +from heat.engine import attributes +from heat.tests import common + +test_attribute_schema = { + "attribute1": "A description for attribute 1", + "attribute2": "A description for attribute 2", + "another attribute": "The last attribute" +} + + +class AttributeTest(common.HeatTestCase): + """Test the Attribute class.""" + + def setUp(self): + common.HeatTestCase.setUp(self) + self.test_resolver = self.m.CreateMockAnything() + + def test_resolve_attribute(self): + """Test that an Attribute returns a good value based on resolver.""" + test_val = "test value" + # resolved with a good value first + self.test_resolver('test').AndReturn('test value') + # second call resolves to None + self.test_resolver(mox.IgnoreArg()).AndReturn(None) + self.m.ReplayAll() + test_attr = attributes.Attribute("test", "A test attribute", + self.test_resolver) + self.assertEqual(test_val, test_attr.value, + "Unexpected attribute value") + self.assertIsNone(test_attr.value, + "Second attrib value should be None") + + def test_as_output(self): + """Test that Attribute looks right when viewed as an Output.""" + expected = { + "test1": { + "Value": '{"Fn::GetAtt": ["test_resource", "test1"]}', + "Description": "The first test attribute" + } + } + self.assertEqual(expected, + attributes.Attribute.as_output( + "test_resource", + "test1", + "The first test attribute"), + 'Attribute as Output mismatch') + + +class AttributesTest(common.HeatTestCase): + """Test the Attributes class.""" + + attributes_schema = { + "test1": "Test attrib 1", + "test2": "Test attrib 2", + "test3": "Test attrib 3" + } + + def test_get_attribute(self): + """Test that we get the attribute values we expect.""" + test_resolver = lambda x: "value1" + self.m.ReplayAll() + attribs = attributes.Attributes('test resource', + self.attributes_schema, + test_resolver) + self.assertEqual("value1", attribs['test1']) + self.assertRaises(KeyError, attribs.__getitem__, 'not there') + + def test_as_outputs(self): + """Test that Output format works as expected.""" + expected = { + "test1": { + "Value": '{"Fn::GetAtt": ["test_resource", "test1"]}', + "Description": "Test attrib 1" + }, + "test2": { + "Value": '{"Fn::GetAtt": ["test_resource", "test2"]}', + "Description": "Test attrib 2" + }, + "test3": { + "Value": '{"Fn::GetAtt": ["test_resource", "test3"]}', + "Description": "Test attrib 3" + } + } + MyTestResourceClass = self.m.CreateMockAnything() + MyTestResourceClass.attributes_schema = { + "test1": "Test attrib 1", + "test2": "Test attrib 2", + "test3": "Test attrib 3" + } + self.m.ReplayAll() + self.assertEqual( + expected, + attributes.Attributes.as_outputs("test_resource", + MyTestResourceClass))