Switch to restart_on_change as context manager

The restart_on_change function is now both a decorator and a context
manager. Using it as a context manager is preferred.

func-test-pr: https://github.com/openstack-charmers/zaza-openstack-tests/pull/527

Depends On: https://github.com/juju/charm-helpers/pull/589

Closes-Bug: #1917792

Change-Id: Ifcabf6b233f467a66982957211b40b83cfccd7ef

src/lib/charm/openstack/mysql_router.py

@@ -29,7 +29,6 @@ import charmhelpers.contrib.network.ip as ch_net_ip
 import charmhelpers.contrib.database.mysql as mysql
 
 import charmhelpers.contrib.openstack.templating as os_templating
-import charmhelpers.contrib.openstack.utils as os_utils
 
 
 # Flag Strings
@@ -643,15 +642,10 @@ class MySQLRouterCharm(charms_openstack.charm.OpenStackCharm):
             ch_core.hookenv.log("TLS mode PREFERRED", "DEBUG")
             _parameters["DEFAULT"] = {"client_ssl_mode": "PREFERRED"}
 
-        # NOTE: LP Bug #1917792
-        # Switch to context manager when work there is completed
-        @os_utils.pausable_restart_on_change(
-            self.restart_map, restart_functions=self.restart_functions)
-        def _config_changed(self, parameters):
+        with ch_core.host.restart_on_change(
+                self.restart_map, restart_functions=self.restart_functions):
             ch_core.hookenv.log("Updating configuration parameters", "DEBUG")
-            self.update_config_parameters(parameters)
-
-        _config_changed(self, _parameters)
+            self.update_config_parameters(_parameters)
 
     @tenacity.retry(wait=tenacity.wait_fixed(10),
                     retry=tenacity.retry_if_exception_type(

src/tests/tests.yaml

@@ -10,8 +10,10 @@ configure:
     - zaza.openstack.charm_tests.nova.setup.manage_ssh_key
     - zaza.openstack.charm_tests.keystone.setup.add_demo_user
 tests:
+- zaza.openstack.charm_tests.mysql.tests.MySQLRouterTests
 - zaza.openstack.charm_tests.keystone.tests.AuthenticationAuthorizationTest
 - full_model_ha:
+    - zaza.openstack.charm_tests.mysql.tests.MySQLRouterTests
     - zaza.openstack.charm_tests.keystone.tests.AuthenticationAuthorizationTest
     - zaza.openstack.charm_tests.hacluster.tests.HaclusterScalebackTest
 gate_bundles:

unit_tests/test_lib_charm_openstack_mysql_router.py

@@ -625,20 +625,15 @@ class TestMySQLRouterCharm(test_utils.PatchHelper):
             "auth_cache_ttl": '10',
             "auth_cache_refresh_interval": '7',
         }
-        _mock_decorator = mock.MagicMock()
-        _mock_decorated = mock.MagicMock()
-        _mock_decorator.return_value = _mock_decorated
 
         def _fake_config(key=None):
             return _config_data[key] if key else _config_data
 
         self.patch_object(mysql_router.ch_core.hookenv, "config")
         self.patch_object(mysql_router.os.path, "exists")
-        self.patch_object(mysql_router.os_utils, "pausable_restart_on_change")
+        self.patch_object(mysql_router.ch_core.host, "restart_on_change")
         self.config.side_effect = _fake_config
-        self.pausable_restart_on_change.return_value = _mock_decorator
         self.endpoint_from_flag.return_value = self.db_router
-        self.db_router.ssl_ca.return_value = '"CACERT"'
 
         _mock_update_config_parameters = mock.MagicMock()
         mrc = mysql_router.MySQLRouterCharm()
@@ -654,10 +649,19 @@ class TestMySQLRouterCharm(test_utils.PatchHelper):
         mrc.config_changed()
         _mock_update_config_parameters.assert_not_called()
 
-        # Bootstrapped
+        # With TLS PASSTHROUGH
+        self.db_router.ssl_ca.return_value = '"CACERT"'
         self.exists.return_value = True
         mrc.config_changed()
-        _mock_decorated.assert_has_calls([mock.call(mrc, _params)])
+        _mock_update_config_parameters.assert_called_once_with(_params)
+
+        # With TLS PREFERRED
+        self.db_router.ssl_ca.return_value = None
+        _params["DEFAULT"]["client_ssl_mode"] = "PREFERRED"
+        self.exists.return_value = True
+        _mock_update_config_parameters.reset_mock()
+        mrc.config_changed()
+        _mock_update_config_parameters.assert_called_once_with(_params)
 
     def test_custom_restart_function(self):
         self.patch_object(mysql_router.ch_core.host, "service_stop")