Add parser for k8s manifest

When creating a service/pod, Magnum needs its name and more additional
information to store database.
This parser allows it.

Change-Id: I6e2a028f0caa7dbbd3a6de20aa3c982fb870c24a

magnum/common/k8s_manifest.py

@@ -0,0 +1,68 @@
+#
+#    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.
+
+import json
+
+import six
+import yaml
+
+from magnum.openstack.common._i18n import _
+
+
+if hasattr(yaml, 'CSafeLoader'):
+    yaml_loader = yaml.CSafeLoader
+else:
+    yaml_loader = yaml.SafeLoader
+
+if hasattr(yaml, 'CSafeDumper'):
+    yaml_dumper = yaml.CSafeDumper
+else:
+    yaml_dumper = yaml.SafeDumper
+
+
+def _construct_yaml_str(self, node):
+    # Override the default string handling function
+    # to always return unicode objects
+    return self.construct_scalar(node)
+yaml_loader.add_constructor(u'tag:yaml.org,2002:str', _construct_yaml_str)
+# Unquoted dates like 2013-05-23 in yaml files get loaded as objects of type
+# datetime.data which causes problems in API layer when being processed by
+# openstack.common.jsonutils. Therefore, make unicode string out of timestamps
+# until jsonutils can handle dates.
+yaml_loader.add_constructor(u'tag:yaml.org,2002:timestamp',
+                            _construct_yaml_str)
+
+
+def parse(manifest_str):
+    '''Takes a string and returns a dict containing the parsed structure.
+    This includes determination of whether the string is using the
+    JSON or YAML format.
+    '''
+    if manifest_str.startswith('{'):
+        manifest = json.loads(manifest_str)
+    else:
+        try:
+            manifest = yaml.load(manifest_str, Loader=yaml_loader)
+        except yaml.YAMLError as yea:
+            yea = six.text_type(yea)
+            msg = _('Error parsing manifest: %s') % yea
+            raise ValueError(msg)
+        else:
+            if manifest is None:
+                manifest = {}
+
+    if not isinstance(manifest, dict):
+        raise ValueError(_('The manifest is not a JSON object '
+                           'or YAML mapping.'))
+    # TODO(yuanying): check manifest version
+    return manifest

magnum/tests/common/test_k8s_manifest.py

@@ -0,0 +1,59 @@
+# Copyright 2015 NEC Corporation.  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.
+
+from magnum.common import k8s_manifest
+from magnum.tests import base
+
+
+class K8sManifestTestCase(base.TestCase):
+
+    def test_parse_with_json(self):
+        json_str = '''
+        {
+          "id": "redis-master",
+          "kind": "Service",
+          "apiVersion": "v1beta1",
+          "port": 6379,
+          "containerPort": 6379,
+          "selector": {
+            "name": "redis-master"
+          },
+          "labels": {
+            "name": "redis-master"
+          }
+        }
+        '''
+
+        manifest = k8s_manifest.parse(json_str)
+        self.assertIsInstance(manifest, dict)
+
+    def test_parse_with_yaml(self):
+        yaml_str = '''
+        id: redis-master
+        kind: Service
+        port: 6379
+        containerPort: 6379
+        selector:
+            name: redis-master
+        labels:
+            name: redis-master
+        '''
+
+        manifest = k8s_manifest.parse(yaml_str)
+        self.assertIsInstance(manifest, dict)
+
+    def test_parse_invalid_value(self):
+        invalid_str = 'aoa89**'
+
+        self.assertRaises(ValueError, k8s_manifest.parse, invalid_str)