Open default MySQL port after configuration

Ensure that the default MySQL port, 3306, is opened
as part of the charm configuration, allowing PXC to
be exposed and accessed in environments where firewalling
is enabled (such as AWS or GCE).

Change-Id: I417a70e8faa23248af945de846ba0f3286ffca83
Closes-Bug: 1614205

hooks/percona_hooks.py

@@ -26,6 +26,7 @@ from charmhelpers.core.hookenv import (
     network_get_primary_address,
     charm_name,
     leader_get,
+    open_port,
 )
 from charmhelpers.core.host import (
     service_restart,
@@ -96,6 +97,7 @@ from percona_utils import (
     get_cluster_host_ip,
     client_node_is_ready,
     leader_node_is_ready,
+    DEFAULT_MYSQL_PORT,
 )
 
 
@@ -296,6 +298,8 @@ def config_changed():
     if is_relation_made('nrpe-external-master'):
         update_nrpe_config()
 
+    open_port(DEFAULT_MYSQL_PORT)
+
 
 @hooks.hook('cluster-relation-joined')
 def cluster_joined():

hooks/percona_utils.py

@@ -65,6 +65,7 @@ REPO = """deb http://repo.percona.com/apt {release} main
 deb-src http://repo.percona.com/apt {release} main"""
 SEEDED_MARKER = "{data_dir}/seeded"
 HOSTS_FILE = '/etc/hosts'
+DEFAULT_MYSQL_PORT = 3306
 
 # NOTE(ajkavanagh) - this is 'required' for the pause/resume code for
 # maintenance mode, but is currently not populated as the

unit_tests/test_percona_hooks.py

@@ -206,3 +206,38 @@ class TestNRPERelation(CharmTestCase):
         hooks.update_nrpe_config()
         self.nrpe.add_init_service_checks.assert_called_once_with(
             mock.ANY, ["mysql"], mock.ANY)
+
+
+class TestConfigChanged(CharmTestCase):
+
+    TO_PATCH = [
+        'log',
+        'open_port',
+        'config',
+        'is_unit_paused_set',
+        'get_cluster_hosts',
+        'is_bootstrapped',
+        'is_leader',
+        'render_config_restart_on_changed',
+        'update_shared_db_rels',
+        'install_mysql_ocf',
+        'relation_ids',
+        'is_relation_made',
+        'ha_relation_joined',
+        'update_nrpe_config',
+        'assert_charm_supports_ipv6',
+    ]
+
+    def setUp(self):
+        CharmTestCase.setUp(self, hooks, self.TO_PATCH)
+        self.config.side_effect = self.test_config.get
+
+    def test_config_changed_open_port(self):
+        '''Ensure open_port is called with MySQL default port'''
+        self.is_unit_paused_set.return_value = False
+        self.is_bootstrapped.return_value = False
+        self.is_leader.return_value = False
+        self.relation_ids.return_value = []
+        self.is_relation_made.return_value = False
+        hooks.config_changed()
+        self.open_port.assert_called_with(3306)