From e549217a407474918046a4d66624cfa20375bffb Mon Sep 17 00:00:00 2001
From: Kiall Mac Innes <kiall@hp.com>
Date: Tue, 21 Oct 2014 14:01:54 +0100
Subject: [PATCH] Support Nested/Recursive Object Validations

This allows for Objects to reference other objects's schemas for use
by JSON-Schema validations. Lookups are performed via the Object
Registry using a pseudo URI scheme of "obj://" e.g.

    '$ref': 'obj://TestObject#/'

Is a JSON-Schema reference, pointing towards the root of the Schema
generated for the "TestObject" object.

Change-Id: Id35c38536eb0d21bb66d3ca720d18e7f6ee733b5
Blueprint: validation-cleanup
---
 designate/objects/base.py                 | 19 +++++++-
 designate/tests/test_objects/test_base.py | 55 +++++++++++++++++++++++
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/designate/objects/base.py b/designate/objects/base.py
index 29d02444..d5681612 100644
--- a/designate/objects/base.py
+++ b/designate/objects/base.py
@@ -13,8 +13,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 import copy
+import urlparse
 
 import six
+import jsonschema
 
 from designate.openstack.common import log as logging
 from designate import exceptions
@@ -70,6 +72,18 @@ def make_class_properties(cls):
         setattr(cls, field, property(getter, setter))
 
 
+def _schema_ref_resolver(uri):
+    """
+    Fetches an DesignateObject's schema from a JSON Schema Reference URI
+
+    Sample URI: obj://ObjectName#/subpathA/subpathB
+    """
+    obj_name = urlparse.urlsplit(uri).netloc
+    obj = DesignateObject.obj_cls_from_name(obj_name)
+
+    return obj.obj_get_schema()
+
+
 def make_class_validator(cls):
     schema = {
         '$schema': 'http://json-schema.org/draft-04/hyper-schema',
@@ -87,8 +101,11 @@ def make_class_validator(cls):
         if properties.get('required', False):
             schema['required'].append(name)
 
+    resolver = jsonschema.RefResolver.from_schema(
+        schema, handlers={'obj': _schema_ref_resolver})
+
     cls._obj_validator = validators.Draft4Validator(
-        schema, format_checker=format.draft4_format_checker)
+        schema, resolver=resolver, format_checker=format.draft4_format_checker)
 
 
 class DesignateObjectMetaclass(type):
diff --git a/designate/tests/test_objects/test_base.py b/designate/tests/test_objects/test_base.py
index 55906d22..b8c3aca0 100644
--- a/designate/tests/test_objects/test_base.py
+++ b/designate/tests/test_objects/test_base.py
@@ -51,6 +51,11 @@ class TestValidatableObject(objects.DesignateObject):
             },
             'required': True,
         },
+        'nested': {
+            'schema': {
+                '$ref': 'obj://TestValidatableObject#/'
+            }
+        }
     }
 
 
@@ -244,6 +249,26 @@ class DesignateObjectTest(tests.TestCase):
         # ID is now a UUID, So - Valid.
         self.assertTrue(obj.is_valid)
 
+    def test_is_valid_recursive(self):
+        obj = TestValidatableObject(
+            id='MyID',
+            nested=TestValidatableObject(id='MyID'))
+
+        # ID should be a UUID, So - Not Valid.
+        self.assertFalse(obj.is_valid)
+
+        # Correct the outer objects ID field
+        obj.id = 'ffded5c4-e4f6-4e02-a175-48e13c5c12a0'
+
+        # Outer ID is now a UUID, Nested ID is Not. So - Invalid.
+        self.assertFalse(obj.is_valid)
+
+        # Correct the nested objects ID field
+        obj.nested.id = 'ffded5c4-e4f6-4e02-a175-48e13c5c12a0'
+
+        # Outer and Nested IDs are now UUIDs. So - Valid.
+        self.assertTrue(obj.is_valid)
+
     def test_validate(self):
         obj = TestValidatableObject()
 
@@ -262,6 +287,36 @@ class DesignateObjectTest(tests.TestCase):
         obj.id = 'ffded5c4-e4f6-4e02-a175-48e13c5c12a0'
         obj.validate()
 
+    def test_validate_recursive(self):
+        obj = TestValidatableObject(
+            id='MyID',
+            nested=TestValidatableObject(id='MyID'))
+
+        # ID should be a UUID, So - Invalid.
+        with testtools.ExpectedException(exceptions.InvalidObject):
+            obj.validate()
+
+        # Correct the outer objects ID field
+        obj.id = 'ffded5c4-e4f6-4e02-a175-48e13c5c12a0'
+
+        # Outer ID is now set, Inner ID is not, still invalid.
+        e = self.assertRaises(exceptions.InvalidObject, obj.validate)
+
+        # Ensure we have exactly one error and fetch it
+        self.assertEqual(1, len(e.errors))
+        error = e.errors.pop(0)
+
+        # Ensure the format validator has triggered the failure.
+        self.assertEqual('format', error.validator)
+
+        # Ensure the nested ID field has triggered the failure.
+        self.assertEqual('nested.id', error.absolute_path)
+        self.assertEqual('nested.id', error.relative_path)
+
+        # Set the Nested ID field to a valid value
+        obj.nested.id = 'ffded5c4-e4f6-4e02-a175-48e13c5c12a0'
+        obj.validate()
+
     def test_obj_attr_is_set(self):
         obj = TestObject()