Add versions list function

This patch add a function to query the Glance API versions.

DocImpact

Change-Id: I21eeaee3db4ae23f608b68bb319772ac612975b4
Closes-bug: #1511180

glanceclient/v2/versions.py

@@ -0,0 +1,26 @@
+# Copyright 2015 OpenStack Foundation
+# Copyright 2015 Huawei Corp.
+# All Rights Reserved.
+#
+#    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.
+
+
+class VersionController(object):
+    def __init__(self, http_client):
+        self.http_client = http_client
+
+    def list(self):
+        """List all versions."""
+        url = '/versions'
+        resp, body = self.http_client.get(url)
+        return body.get('versions', None)