[placement] Separate API schemas (usage)

In compute APIs, they have their schemas in the
independent directory (nova/api/openstack/compute/schemas).
Placement APIs should be like that as well.

This patch separates API schemas to an independent directory
(nova/api/openstack/placement/schemas)
from nova/api/openstack/placement/handlers/usage.py.

Subsequent patches will move schemas of other handlers.

Change-Id: I38fc7e848fb3f95d79482e5903679e585e3675cc

nova/api/openstack/placement/handlers/usage.py

@@ -17,6 +17,7 @@ from oslo_utils import timeutils
 import webob
 
 from nova.api.openstack.placement import microversion
+from nova.api.openstack.placement.schemas import usage as schema
 from nova.api.openstack.placement import util
 from nova.api.openstack.placement import wsgi_wrapper
 from nova import exception
@@ -24,28 +25,6 @@ from nova.i18n import _
 from nova.objects import resource_provider as rp_obj
 
 
-# Represents the allowed query string parameters to GET /usages
-GET_USAGES_SCHEMA_1_9 = {
-    "type": "object",
-    "properties": {
-        "project_id": {
-            "type": "string",
-            "minLength": 1,
-            "maxLength": 255,
-        },
-        "user_id": {
-            "type": "string",
-            "minLength": 1,
-            "maxLength": 255,
-        },
-    },
-    "required": [
-        "project_id"
-     ],
-    "additionalProperties": False,
-}
-
-
 def _serialize_usages(resource_provider, usage):
     usage_dict = {resource.resource_class: resource.usage
                   for resource in usage}
@@ -111,9 +90,7 @@ def get_total_usages(req):
     context = req.environ['placement.context']
     want_version = req.environ[microversion.MICROVERSION_ENVIRON]
 
-    schema = GET_USAGES_SCHEMA_1_9
-
-    util.validate_query_params(req, schema)
+    util.validate_query_params(req, schema.GET_USAGES_SCHEMA_1_9)
 
     project_id = req.GET.get('project_id')
     user_id = req.GET.get('user_id')

nova/api/openstack/placement/schemas/usage.py

@@ -0,0 +1,33 @@
+#    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.
+"""Placement API schemas for usage information."""
+
+# Represents the allowed query string parameters to GET /usages
+GET_USAGES_SCHEMA_1_9 = {
+    "type": "object",
+    "properties": {
+        "project_id": {
+            "type": "string",
+            "minLength": 1,
+            "maxLength": 255,
+        },
+        "user_id": {
+            "type": "string",
+            "minLength": 1,
+            "maxLength": 255,
+        },
+    },
+    "required": [
+        "project_id"
+     ],
+    "additionalProperties": False,
+}