Purge old packages on upgrade-charm

On charm upgrade the charm may switch to py3 packages. If so, ensure
the old py2 packages are purged. If the purge occurs then restart
services.

Change-Id: I2f5d95d9688c48e97fbb9b8b11a23d4b6250e016
Closes-Bug: 1803451

hooks/neutron_api_hooks.py

@@ -42,6 +42,7 @@ from charmhelpers.core.hookenv import (
 from charmhelpers.core.host import (
     mkdir,
     service_reload,
+    service_restart,
 )
 
 from charmhelpers.fetch import (
@@ -86,6 +87,7 @@ from neutron_api_utils import (
     check_local_db_actions_complete,
     pause_unit_helper,
     resume_unit_helper,
+    remove_old_packages,
 )
 from neutron_api_context import (
     get_dns_domain,
@@ -295,9 +297,14 @@ def config_changed():
     apt_install(filter_installed_packages(
                 determine_packages(config('openstack-origin'))),
                 fatal=True)
+    packages_removed = remove_old_packages()
     configure_https()
     update_nrpe_config()
     CONFIGS.write_all()
+    if packages_removed and not is_unit_paused_set():
+        log("Package purge detected, restarting services", "INFO")
+        for s in services():
+            service_restart(s)
     for r_id in relation_ids('neutron-api'):
         neutron_api_relation_joined(rid=r_id)
     for r_id in relation_ids('neutron-plugin-api'):

hooks/neutron_api_utils.py

@@ -427,6 +427,18 @@ def determine_purge_packages():
     return []
 
 
+def remove_old_packages():
+    '''Purge any packages that need ot be removed.
+
+    :returns: bool Whether packages were removed.
+    '''
+    installed_packages = filter_missing_packages(determine_purge_packages())
+    if installed_packages:
+        apt_purge(installed_packages, fatal=True)
+        apt_autoremove(purge=True, fatal=True)
+    return bool(installed_packages)
+
+
 def determine_ports():
     '''Assemble a list of API ports for services we are managing'''
     ports = []
@@ -549,10 +561,7 @@ def do_openstack_upgrade(configs):
                 options=dpkg_opts,
                 fatal=True)
 
-    installed_packages = filter_missing_packages(determine_purge_packages())
-    if installed_packages:
-        apt_purge(installed_packages, fatal=True)
-        apt_autoremove(purge=True, fatal=True)
+    remove_old_packages()
 
     # set CONFIGS to load templates from new release
     configs.set_release(openstack_release=new_os_rel)

unit_tests/test_neutron_api_hooks.py

@@ -91,6 +91,9 @@ TO_PATCH = [
     'get_relation_ip',
     'update_dns_ha_resource_params',
     'is_nsg_logging_enabled',
+    'remove_old_packages',
+    'services',
+    'service_restart',
 ]
 NEUTRON_CONF_DIR = "/etc/neutron"
 
@@ -222,6 +225,7 @@ class NeutronAPIHooksTests(CharmTestCase):
             self._call_hook('config-changed')
 
     def test_config_changed_with_openstack_upgrade_action(self):
+        self.remove_old_packages.return_value = False
         self.openstack_upgrade_available.return_value = True
         self.test_config.set('action-managed-upgrade', True)
 
@@ -229,6 +233,14 @@ class NeutronAPIHooksTests(CharmTestCase):
 
         self.assertFalse(self.do_openstack_upgrade.called)
 
+    def test_config_changed_with_purge(self):
+        self.remove_old_packages.return_value = True
+        self.services.return_value = ['neutron-server']
+        self.openstack_upgrade_available.return_value = False
+        self._call_hook('config-changed')
+        self.remove_old_packages.assert_called_once_with()
+        self.service_restart.assert_called_once_with('neutron-server')
+
     def test_amqp_joined(self):
         self._call_hook('amqp-relation-joined')
         self.relation_set.assert_called_with(