Support change of superuser and replication credentials on reload (#445)

Fixes: https://github.com/zalando/patroni/issues/353
and: https://github.com/zalando/patroni/issues/443

patroni/postgresql.py

@@ -99,7 +99,6 @@ class Postgresql(object):
 
         self._connect_address = config.get('connect_address')
         self._superuser = config['authentication'].get('superuser', {})
-        self._replication = config['authentication']['replication']
         self.resolve_connection_addresses()
 
         self._rewind_state = REWIND_STATUS.INITIAL
@@ -156,6 +155,10 @@ class Postgresql(object):
     def use_slots(self):
         return self._use_slots and self._major_version >= 9.4
 
+    @property
+    def _replication(self):
+        return self.config['authentication']['replication']
+
     @property
     def callback(self):
         return self.config.get('callbacks') or {}
@@ -235,6 +238,7 @@ class Postgresql(object):
         return return_codes.get(ret, STATE_UNKNOWN)
 
     def reload_config(self, config):
+        self._superuser = config['authentication'].get('superuser', {})
         server_parameters = self.get_server_parameters(config)
 
         listen_address_changed = pending_reload = pending_restart = False

tests/test_postgresql.py

@@ -585,14 +585,16 @@ class TestPostgresql(unittest.TestCase):
     def test_reload_config(self):
         parameters = self._PARAMETERS.copy()
         parameters.pop('f.oo')
-        self.p.reload_config({'retry_timeout': 10, 'listen': '*', 'parameters': parameters})
+        config = {'authentication': {}, 'retry_timeout': 10, 'listen': '*', 'parameters': parameters}
+        self.p.reload_config(config)
         parameters['b.ar'] = 'bar'
-        self.p.reload_config({'retry_timeout': 10, 'listen': '*', 'parameters': parameters})
+        self.p.reload_config(config)
         parameters['autovacuum'] = 'on'
-        self.p.reload_config({'retry_timeout': 10, 'listen': '*', 'parameters': parameters})
+        self.p.reload_config(config)
         parameters['autovacuum'] = 'off'
         parameters.pop('search_path')
-        self.p.reload_config({'retry_timeout': 10, 'listen': '*:5433', 'parameters': parameters})
+        config['listen'] = '*:5433'
+        self.p.reload_config(config)
 
     @patch.object(Postgresql, '_version_file_exists', Mock(return_value=True))
     def test_get_major_version(self):