From 5b93048e0742907b2d1f9de42781af2af1b6c151 Mon Sep 17 00:00:00 2001
From: Viranch Mehta <email@viranch.me>
Date: Thu, 21 Oct 2021 13:24:45 -0700
Subject: [PATCH] Use null/empty instead of garbage values to invalidate broken
 dynamic records

---
 octodns/provider/azuredns.py            | 42 +++++++++++--------------
 tests/test_octodns_provider_azuredns.py | 12 +++----
 2 files changed, 24 insertions(+), 30 deletions(-)

diff --git a/octodns/provider/azuredns.py b/octodns/provider/azuredns.py
index aff7a25..bbc6973 100644
--- a/octodns/provider/azuredns.py
+++ b/octodns/provider/azuredns.py
@@ -650,14 +650,12 @@ class AzureProvider(BaseProvider):
         if azrecord.a_records is None:
             if azrecord.target_resource.id:
                 return self._data_for_dynamic(azrecord)
-            else:
-                # dynamic record alias is broken, return dummy value and apply
-                # will likely overwrite/fix it
-                self.log.warn('_data_for_A: Missing Traffic Manager '
-                              'alias for dynamic A record %s, forcing '
-                              're-link by setting an invalid value',
-                              azrecord.fqdn)
-                return {'values': ['255.255.255.255']}
+
+            # dynamic record alias is broken, return dummy value and apply
+            # will likely overwrite/fix it
+            self.log.warn('_data_for_A: Missing Traffic Manager alias for '
+                          'dynamic record %s', azrecord.fqdn)
+            return {'values': []}
 
         return {'values': [ar.ipv4_address for ar in azrecord.a_records]}
 
@@ -665,14 +663,12 @@ class AzureProvider(BaseProvider):
         if azrecord.aaaa_records is None:
             if azrecord.target_resource.id:
                 return self._data_for_dynamic(azrecord)
-            else:
-                # dynamic record alias is broken, return dummy value and apply
-                # will likely overwrite/fix it
-                self.log.warn('_data_for_AAAA: Missing Traffic Manager '
-                              'alias for dynamic AAAA record %s, forcing '
-                              're-link by setting an invalid value',
-                              azrecord.fqdn)
-                return {'values': ['::1']}
+
+            # dynamic record alias is broken, return dummy value and apply
+            # will likely overwrite/fix it
+            self.log.warn('_data_for_AAAA: Missing Traffic Manager alias for '
+                          'dynamic record %s', azrecord.fqdn)
+            return {'values': []}
 
         return {'values': [ar.ipv6_address for ar in azrecord.aaaa_records]}
 
@@ -692,14 +688,12 @@ class AzureProvider(BaseProvider):
         if azrecord.cname_record is None:
             if azrecord.target_resource.id:
                 return self._data_for_dynamic(azrecord)
-            else:
-                # dynamic record alias is broken, return dummy value and apply
-                # will likely overwrite/fix it
-                self.log.warn('_data_for_CNAME: Missing Traffic Manager '
-                              'alias for dynamic CNAME record %s, forcing '
-                              're-link by setting an invalid value',
-                              azrecord.fqdn)
-                return {'value': 'iam.invalid.'}
+
+            # dynamic record alias is broken, return dummy value and apply
+            # will likely overwrite/fix it
+            self.log.warn('_data_for_CNAME: Missing Traffic Manager alias for '
+                          'dynamic record %s', azrecord.fqdn)
+            return {'value': None}
 
         return {'value': _check_endswith_dot(azrecord.cname_record.cname)}
 
diff --git a/tests/test_octodns_provider_azuredns.py b/tests/test_octodns_provider_azuredns.py
index 708b229..64bd3ec 100644
--- a/tests/test_octodns_provider_azuredns.py
+++ b/tests/test_octodns_provider_azuredns.py
@@ -1934,8 +1934,8 @@ class TestAzureDnsProvider(TestCase):
             ttl=60, target_resource=SubResource(id=None))
         azrecord.name = record.name or '@'
         azrecord.type = f'Microsoft.Network/dnszones/{record._type}'
-        record2 = provider._populate_record(zone, azrecord)
-        self.assertEqual(record2.values, ['255.255.255.255'])
+        record2 = provider._populate_record(zone, azrecord, lenient=True)
+        self.assertEqual(record2.values, [])
 
         # test that same record gets populated back from traffic managers
         tm_list = provider._tm_client.profiles.list_by_resource_group
@@ -2016,8 +2016,8 @@ class TestAzureDnsProvider(TestCase):
             ttl=60, target_resource=SubResource(id=None))
         azrecord.name = record.name or '@'
         azrecord.type = f'Microsoft.Network/dnszones/{record._type}'
-        record2 = provider._populate_record(zone, azrecord)
-        self.assertEqual(record2.values, ['::1'])
+        record2 = provider._populate_record(zone, azrecord, lenient=True)
+        self.assertEqual(record2.values, [])
 
         # test that same record gets populated back from traffic managers
         tm_list = provider._tm_client.profiles.list_by_resource_group
@@ -2259,8 +2259,8 @@ class TestAzureDnsProvider(TestCase):
         azrecord.name = record1.name or '@'
         azrecord.type = f'Microsoft.Network/dnszones/{record1._type}'
 
-        record2 = provider._populate_record(zone, azrecord)
-        self.assertEqual(record2.value, 'iam.invalid.')
+        record2 = provider._populate_record(zone, azrecord, lenient=True)
+        self.assertIsNone(record2.value)
 
         change = Update(record2, record1)
         provider._apply_Update(change)