service: Add privileged utility for 'try-reload-or-restart' action

Reload a service if it supports reloading, otherwise restart. Do nothing if
service is not running.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/action_utils.py

@@ -135,6 +135,14 @@ def service_reload(service_name):
     service_action(service_name, 'reload')
 
 
+def service_try_reload_or_restart(service_name):
+    """Reload a service if it supports reloading, otherwise restart.
+
+    Do nothing if service is not running.
+    """
+    service_action(service_name, 'try-reload-or-restart')
+
+
 def service_action(service_name, action):
     """Perform the given action on the service_name."""
     subprocess.run(['systemctl', action, service_name],

plinth/privileged/__init__.py

@@ -5,11 +5,12 @@ from .config import dropin_is_valid, dropin_link, dropin_unlink
 from .packages import (filter_conffile_packages, install,
                        is_package_manager_busy, remove, update)
 from .service import (disable, enable, is_enabled, is_running, mask, reload,
-                      restart, start, stop, try_restart, unmask)
+                      restart, start, stop, try_reload_or_restart, try_restart,
+                      unmask)
 
 __all__ = [
     'filter_conffile_packages', 'install', 'is_package_manager_busy', 'remove',
     'update', 'disable', 'enable', 'is_enabled', 'is_running', 'mask',
-    'reload', 'restart', 'start', 'stop', 'try_restart', 'unmask',
-    'dropin_is_valid', 'dropin_link', 'dropin_unlink'
+    'reload', 'restart', 'start', 'stop', 'try_reload_or_restart',
+    'try_restart', 'unmask', 'dropin_is_valid', 'dropin_link', 'dropin_unlink'
 ]

plinth/privileged/service.py

@@ -57,6 +57,16 @@ def reload(service: str):
     action_utils.service_reload(service)
 
 
+@privileged
+def try_reload_or_restart(service: str):
+    """Reload a service if it supports reloading, otherwise restart.
+
+    Do nothing if service is not running.
+    """
+    _assert_service_is_managed_by_plinth(service)
+    action_utils.service_try_reload_or_restart(service)
+
+
 @privileged
 def mask(service: str):
     """Mask a service."""

plinth/tests/test_action_utils.py

@@ -16,6 +16,7 @@ from plinth.action_utils import (get_addresses, get_hostname,
                                  service_is_enabled, service_is_running,
                                  service_reload, service_restart,
                                  service_start, service_stop,
+                                 service_try_reload_or_restart,
                                  service_try_restart, service_unmask)
 
 UNKNOWN = 'unknowndeamon'
@@ -86,6 +87,8 @@ def test_service_actions(mock):
     mock.assert_called_with(UNKNOWN, 'try-restart')
     service_reload(UNKNOWN)
     mock.assert_called_with(UNKNOWN, 'reload')
+    service_try_reload_or_restart(UNKNOWN)
+    mock.assert_called_with(UNKNOWN, 'try-reload-or-restart')
 
 
 @pytest.mark.usefixtures('needs_root')