Move tags validation code to json schema

Currently  we have lot of validation code inside
server tag controller class which can be moved to
json schema.

Same can be reused on other place also.
For example, microversion 2.40 adds server tag while
boot. Same schema can be used there.

Current python code validation shows conceret error message about each
tag where using json schema error msg will be like below-

For requesting tags more than max limit:
Invalid input for field/attribute tags. Value: ['0', '1', '2', '3', '4',
'5', '6', ...] is too long

For requesting tags more than char limit:
Invalid input for field/attribute 0. Value: aaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.
'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' is too
long

I think those error message are clear enough to understand the wrong
tags.

Change-Id: I457cf630aeae9034c0b175d016148a1d50a0b469

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

@@ -10,20 +10,17 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from nova.api.validation import parameter_types
+from nova.objects import instance
+
 update_all = {
-    "definitions": {
-        "tag": {
-            "type": "string"
-        }
-    },
     "title": "Server tags",
     "type": "object",
     "properties": {
         "tags": {
             "type": "array",
-            "items": {
-                "$ref": "#/definitions/tag"
-            }
+            "items": parameter_types.tag,
+            "maxItems": instance.MAX_TAG_COUNT
         }
     },
     'required': ['tags'],

nova/api/openstack/compute/server_tags.py

@@ -109,12 +109,6 @@ def update(self, req, server_id, id, body):
                    % objects.instance.MAX_TAG_COUNT)
             raise webob.exc.HTTPBadRequest(explanation=msg)
 
-        if len(id) > objects.tag.MAX_TAG_LENGTH:
-            msg = (_("Tag '%(tag)s' is too long. Maximum length of a tag "
-                     "is %(length)d") % {'tag': id,
-                                         'length': objects.tag.MAX_TAG_LENGTH})
-            raise webob.exc.HTTPBadRequest(explanation=msg)
-
         if id in _get_tags_names(tags):
             # NOTE(snikitin): server already has specified tag
             return webob.Response(status_int=204)
@@ -139,33 +133,6 @@ def update_all(self, req, server_id, body):
         context.can(st_policies.POLICY_ROOT % 'update_all')
         self._check_instance_in_valid_state(context, server_id, 'update tags')
 
-        invalid_tags = []
-        for tag in body['tags']:
-            try:
-                jsonschema.validate(tag, parameter_types.tag)
-            except jsonschema.ValidationError:
-                invalid_tags.append(tag)
-        if invalid_tags:
-            msg = (_("Tags '%s' are invalid. Each tag must be a string "
-                     "without characters '/' and ','.") % invalid_tags)
-            raise webob.exc.HTTPBadRequest(explanation=msg)
-
-        tag_count = len(body['tags'])
-        if tag_count > objects.instance.MAX_TAG_COUNT:
-            msg = (_("The number of tags exceeded the per-server limit "
-                     "%(max)d. The number of tags in request is %(count)d.")
-                   % {'max': objects.instance.MAX_TAG_COUNT,
-                      'count': tag_count})
-            raise webob.exc.HTTPBadRequest(explanation=msg)
-
-        long_tags = [
-            t for t in body['tags'] if len(t) > objects.tag.MAX_TAG_LENGTH]
-        if long_tags:
-            msg = (_("Tags %(tags)s are too long. Maximum length of a tag "
-                     "is %(length)d") % {'tags': long_tags,
-                                         'length': objects.tag.MAX_TAG_LENGTH})
-            raise webob.exc.HTTPBadRequest(explanation=msg)
-
         try:
             tags = objects.TagList.create(context, server_id, body['tags'])
         except exception.InstanceNotFound as e:

nova/api/validation/parameter_types.py

@@ -23,6 +23,7 @@
 
 from nova import db
 from nova.i18n import _
+from nova.objects import tag
 
 
 class ValidationRegex(object):
@@ -398,5 +399,6 @@ def valid_char(char):
 
 tag = {
     "type": "string",
+    "maxLength": tag.MAX_TAG_LENGTH,
     "pattern": "^[^,/]*$"
 }

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

@@ -103,14 +103,15 @@ def test_update_all_too_many_tags(self):
 
         req = self._get_request(
             '/v2/fake/servers/%s/tags' % UUID, 'PUT')
-        self.assertRaises(exc.HTTPBadRequest, self.controller.update_all,
+        self.assertRaises(exception.ValidationError,
+                          self.controller.update_all,
                           req, UUID, body=fake_tags)
 
     def test_update_all_forbidden_characters(self):
         self.stub_out('nova.api.openstack.common.get_instance', return_server)
         req = self._get_request('/v2/fake/servers/%s/tags' % UUID, 'PUT')
         for tag in ['tag,1', 'tag/1']:
-            self.assertRaises(exc.HTTPBadRequest,
+            self.assertRaises(exception.ValidationError,
                               self.controller.update_all,
                               req, UUID, body={'tags': [tag, 'tag2']})
 
@@ -124,7 +125,8 @@ def test_update_all_too_long_tag(self):
         self.stub_out('nova.api.openstack.common.get_instance', return_server)
         req = self._get_request('/v2/fake/servers/%s/tags' % UUID, 'PUT')
         tag = "a" * (tag_obj.MAX_TAG_LENGTH + 1)
-        self.assertRaises(exc.HTTPBadRequest, self.controller.update_all,
+        self.assertRaises(exception.ValidationError,
+                          self.controller.update_all,
                           req, UUID, body={'tags': [tag]})
 
     def test_update_all_invalid_tag_list_type(self):