pagekite: restart service when config is changed

so the changed config gets applied immediately, and
not only after enabling/disabling the service manually.

actions/pagekite

@@ -54,6 +54,7 @@ def parse_arguments():
     subparsers.add_parser('is-running', help='Get whether PakeKite is running')
     subparsers.add_parser('start-and-enable', help='Enable PageKite service')
     subparsers.add_parser('stop-and-disable', help='Disable PageKite service')
+    subparsers.add_parser('restart', help='Restart PageKite service')
 
     # Frontend
     subparsers.add_parser('get-frontend', help='Get pagekite frontend')
@@ -95,6 +96,12 @@ def subcommand_is_running(_):
     print 'yes' if util.service_is_running('pagekite') else 'no'
 
 
+def subcommand_restart(_):
+    """Restart the pagekite service"""
+    _service('restart')
+    print 'restarted'
+
+
 def subcommand_start_and_enable(_):
     aug.remove(PATHS['abort_not_configured'])
     aug.save()

plinth/modules/pagekite/forms.py

@@ -70,15 +70,18 @@ for your account if no secret is set on the kite'))
 
         if old != new:
 
+            config_changed = False
             if old['kite_name'] != new['kite_name'] or \
                     old['kite_secret'] != new['kite_secret']:
                 _run(['set-kite', '--kite-name', new['kite_name'],
                       '--kite-secret', new['kite_secret']])
                 messages.success(request, _('Kite details set'))
+                config_changed = True
 
             if old['server'] != new['server']:
                 _run(['set-frontend', new['server']])
                 messages.success(request, _('Pagekite server set'))
+                config_changed = True
 
             if old['enabled'] != new['enabled']:
                 if new['enabled']:
@@ -88,6 +91,11 @@ for your account if no secret is set on the kite'))
                     _run(['stop-and-disable'])
                     messages.success(request, _('PageKite disabled'))
 
+            # Restart the service if the config was changed while the service
+            # was running, so the changes take effect.
+            elif config_changed and new['enabled']:
+                _run(['restart'])
+
 
 class DefaultServiceForm(forms.Form):
     """Creates a form out of PREDEFINED_SERVICES"""