Describe API versions

Adding json representation of the v2 REST API at the API root
endpoint. Endpoint still requires authentication.

Change-Id: I069644917f9a29e7ddfe7010695ad3a5aa5ca8c2
Partial-Bug: #1350076

ceilometer/api/controllers/root.py

@@ -19,12 +19,39 @@ import pecan
 
 from ceilometer.api.controllers import v2
 
+MEDIA_TYPE_JSON = 'application/vnd.openstack.telemetry-%s+json'
+MEDIA_TYPE_XML = 'application/vnd.openstack.telemetry-%s+xml'
+
 
 class RootController(object):
 
     v2 = v2.V2Controller()
 
-    @pecan.expose(generic=True, template='index.html')
+    @pecan.expose('json')
     def index(self):
-        # FIXME: Return version information
-        return dict()
+        base_url = pecan.request.host_url
+        available = [{'tag': 'v2', 'date': '2013-02-13T00:00:00Z', }]
+        collected = [version_descriptor(base_url, v['tag'], v['date'])
+                     for v in available]
+        versions = {'versions': {'values': collected}}
+        return versions
+
+
+def version_descriptor(base_url, version, released_on):
+    url = version_url(base_url, version)
+    return {
+        'id': version,
+        'links': [
+            {'href': url, 'rel': 'self', },
+            {'href': 'http://docs.openstack.org/',
+             'rel': 'describedby', 'type': 'text/html', }],
+        'media-types': [
+            {'base': 'application/json', 'type': MEDIA_TYPE_JSON % version, },
+            {'base': 'application/xml', 'type': MEDIA_TYPE_XML % version, }],
+        'status': 'stable',
+        'updated': released_on,
+    }
+
+
+def version_url(base_url, version_number):
+    return '%s/%s' % (base_url, version_number)

ceilometer/tests/api/test_versions.py

@@ -0,0 +1,65 @@
+# Copyright 2014 OpenStack Foundation
+#
+# 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 ceilometer.tests import api
+
+V2_MEDIA_TYPES = [
+    {
+        'base': 'application/json',
+        'type': 'application/vnd.openstack.telemetry-v2+json'
+    }, {
+        'base': 'application/xml',
+        'type': 'application/vnd.openstack.telemetry-v2+xml'
+    }
+]
+
+V2_HTML_DESCRIPTION = {
+    'href': 'http://docs.openstack.org/',
+    'rel': 'describedby',
+    'type': 'text/html',
+}
+
+V2_EXPECTED_RESPONSE = {
+    'id': 'v2',
+    'links': [
+        {
+            'rel': 'self',
+            'href': 'http://localhost/v2',
+        },
+        V2_HTML_DESCRIPTION
+    ],
+    'media-types': V2_MEDIA_TYPES,
+    'status': 'stable',
+    'updated': '2013-02-13T00:00:00Z',
+}
+
+V2_VERSION_RESPONSE = {
+    "version": V2_EXPECTED_RESPONSE
+}
+
+VERSIONS_RESPONSE = {
+    "versions": {
+        "values": [
+            V2_EXPECTED_RESPONSE
+        ]
+    }
+}
+
+
+class TestVersions(api.FunctionalTest):
+
+    def test_versions(self):
+        data = self.get_json('/')
+        self.assertEqual(VERSIONS_RESPONSE, data)