Enable 'null' value for user_data in V2.1 API

The legacy v2 API allow the 'null' value for user_data. Unfortunately
the v2.1 API didn't match that in the input validation. This patch
enables 'null' value, at sametime, it enables for v2.1 compat mode
also.

Conflicts:
        api-ref/source/parameters.yaml

NOTE(mriedem): The conflict is due to the api-ref parameters file
not existing until Newton. It's just a note in the docs on the
user_data parameter and isn't required for this backport.

Change-Id: Iae614035efd4b37c214754ad12b17ca224b8fd92
Closes-Bug: #1582911
(cherry picked from commit 22c87390a3)

nova/api/openstack/compute/schemas/user_data.py

@@ -18,3 +18,13 @@ server_create = {
         'format': 'base64'
     },
 }
+
+
+server_create_v20 = {
+    'user_data': {
+        'oneOf': [
+            {'type': 'string', 'format': 'base64'},
+            {'type': 'null'},
+        ],
+    },
+}

nova/api/openstack/compute/user_data.py

@@ -39,4 +39,6 @@ class UserData(extensions.V21APIExtensionBase):
         create_kwargs['user_data'] = server_dict.get(ATTRIBUTE_NAME)
 
     def get_server_create_schema(self, version):
+        if version == '2.0':
+            return schema_user_data.server_create_v20
         return schema_user_data.server_create

nova/api/validation/validators.py

@@ -48,6 +48,10 @@ def _validate_base64_format(instance):
         base64.decodestring(instance)
     except base64.binascii.Error:
         return False
+    except TypeError:
+        # The name must be string type. If instance isn't string type, the
+        # TypeError will be raised at here.
+        return False
 
     return True
 

nova/tests/unit/api/openstack/compute/test_user_data.py

@@ -16,6 +16,7 @@
 
 import base64
 import datetime
+import mock
 import uuid
 
 from oslo_config import cfg
@@ -135,7 +136,7 @@ class ServersControllerCreateTest(test.TestCase):
                        fake_method)
 
     def _test_create_extra(self, params, no_image=False,
-                           override_controller=None):
+                           override_controller=None, legacy_v2=False):
         image_uuid = 'c905cedb-7281-47e4-8a62-f26bc5fc4c77'
         server = dict(name='server_test', imageRef=image_uuid, flavorRef=2)
         if no_image:
@@ -146,6 +147,8 @@ class ServersControllerCreateTest(test.TestCase):
         req.method = 'POST'
         req.body = jsonutils.dump_as_bytes(body)
         req.headers["content-type"] = "application/json"
+        if legacy_v2:
+            req.set_legacy_v2()
         if override_controller:
             server = override_controller.create(req, body=body).obj['server']
         else:
@@ -187,3 +190,15 @@ class ServersControllerCreateTest(test.TestCase):
         params = {user_data.ATTRIBUTE_NAME: value}
         self.assertRaises(exception.ValidationError,
                           self._test_create_extra, params)
+
+    @mock.patch('nova.compute.api.API.create')
+    def test_create_instance_with_none_allowd_for_v20_compat_mode(self,
+            mock_create):
+
+        def create(context, *args, **kwargs):
+            self.assertIsNone(kwargs['user_data'])
+            return ([fakes.stub_instance_obj(context)], None)
+
+        mock_create.side_effect = create
+        params = {user_data.ATTRIBUTE_NAME: None}
+        self._test_create_extra(params, legacy_v2=True)