Empty RecordSets can be re-provisioned

An empty recordset is just a logical entity with a given record type.
Right now we save the recordset name and type even when it is a null set,
thus preventing us from re-using the name as a different type (eg. A to
CNAME). It would be better to check for this empty recordset condition
and delete if possible, rather than throwing error 400.
This commit also adds CNAME type to Record and RecordSet fixtures
Closes-Bug: #1304088

Change-Id: I4dd0e7def848939d8f0053a5ca40b14a0b68b8b3

designate/api/v1/records.py

@@ -203,6 +203,15 @@ def update_record(domain_id, record_id):
     return flask.jsonify(record_schema.filter(record))
 
 
+def _delete_recordset_if_empty(context, domain_id, recordset_id):
+    recordset = get_central_api().find_recordset(context, {
+        'id': recordset_id
+    })
+    # Make sure it's the right recordset
+    if len(recordset.records) == 0:
+        get_central_api().delete_recordset(context, domain_id, recordset_id)
+
+
 @blueprint.route('/domains/<uuid:domain_id>/records/<uuid:record_id>',
                  methods=['DELETE'])
 def delete_record(domain_id, record_id):
@@ -219,4 +228,5 @@ def delete_record(domain_id, record_id):
     get_central_api().delete_record(
         context, domain_id, record['recordset_id'], record_id)
 
+    _delete_recordset_if_empty(context, domain_id, record['recordset_id'])
     return flask.Response(status=200)

designate/tests/__init__.py

@@ -204,6 +204,10 @@ class TestCase(base.BaseTestCase):
             {'name': '_sip._tcp.%s', 'type': 'SRV'},
             {'name': '_sip._udp.%s', 'type': 'SRV'},
         ],
+        'CNAME': [
+            {'name': 'www.%s', 'type': 'CNAME'},
+            {'name': 'sub1.%s', 'type': 'CNAME'},
+        ]
     }
 
     record_fixtures = {
@@ -218,6 +222,10 @@ class TestCase(base.BaseTestCase):
         'SRV': [
             {'data': '0 5060 server1.example.org.', 'priority': 5},
             {'data': '1 5060 server2.example.org.', 'priority': 10},
+        ],
+        'CNAME': [
+            {'data': 'www.somedomain.org.'},
+            {'data': 'www.someotherdomain.com.'},
         ]
     }
 

designate/tests/test_api/test_v1/test_records.py

@@ -65,6 +65,55 @@ def test_create_record_existing_recordset(self):
         self.assertIn('name', response.json)
         self.assertEqual(response.json['name'], fixture['name'])
 
+    def test_create_record_name_reuse(self):
+        fixture_1 = self.get_record_fixture(self.recordset['type'])
+        fixture_1.update({
+            'name': self.recordset['name'],
+            'type': self.recordset['type'],
+        })
+
+        fixture_2 = self.get_record_fixture(self.recordset['type'], fixture=1)
+        fixture_2.update({
+            'name': self.recordset['name'],
+            'type': self.recordset['type'],
+        })
+
+        # Create 2 records
+        record_1 = self.post('domains/%s/records' % self.domain['id'],
+                             data=fixture_1)
+        record_2 = self.post('domains/%s/records' % self.domain['id'],
+                             data=fixture_2)
+
+        # Delete record 1, this should not have any side effects
+        self.delete('domains/%s/records/%s' % (self.domain['id'],
+                                               record_1.json['id']))
+
+        # Get the record 2 to ensure recordset did not get deleted
+        rec_2_get_response = self.get('domains/%s/records/%s' %
+                                     (self.domain['id'], record_2.json['id']))
+
+        self.assertIn('id', rec_2_get_response.json)
+        self.assertIn('name', rec_2_get_response.json)
+        self.assertEqual(rec_2_get_response.json['name'], fixture_1['name'])
+
+        # Delete record 2, this should delete the null recordset too
+        self.delete('domains/%s/records/%s' % (self.domain['id'],
+                                               record_2.json['id']))
+
+        # Re-create as a different type, but use the same name
+        fixture = self.get_record_fixture('CNAME')
+        fixture.update({
+            'name': self.recordset['name'],
+            'type': 'CNAME'
+        })
+
+        response = self.post('domains/%s/records' % self.domain['id'],
+                             data=fixture)
+
+        self.assertIn('id', response.json)
+        self.assertIn('name', response.json)
+        self.assertEqual(response.json['name'], fixture['name'])
+
     def test_create_record_junk(self):
         fixture = self.get_record_fixture(self.recordset['type'])
         fixture.update({