[config] Don't attempt to restart disabled services (#944)

When restarting services, don't attempt to restart a service if it is disabled/masked or the `systemctl restart` command will fail, causing the calling command (e.g., `config load`, `config reload`, `config load_minigraph`) to error out.

config/main.py

@@ -490,6 +490,32 @@ def _abort_if_false(ctx, param, value):
  if not value:
  ctx.abort()
 
+
+def _get_disabled_services_list():
+ disabled_services_list = []
+
+ config_db = ConfigDBConnector()
+ config_db.connect()
+ feature_table = config_db.get_table('FEATURE')
+ if feature_table is not None:
+ for feature_name in feature_table.keys():
+ if not feature_name:
+ log_warning("Feature is None")
+ continue
+
+ status = feature_table[feature_name]['status']
+ if not status:
+ log_warning("Status of feature '{}' is None".format(feature_name))
+ continue
+
+ if status == "disabled":
+ disabled_services_list.append(feature_name)
+ else:
+ log_warning("Unable to retreive FEATURE table")
+
+ return disabled_services_list
+
+
 def _stop_services():
  # on Mellanox platform pmon is stopped by syncd
  services_to_stop = [
@@ -507,6 +533,7 @@ def _stop_services():
 
  execute_systemctl(services_to_stop, SYSTEMCTL_ACTION_STOP)
 
+
 def _reset_failed_services():
  services_to_reset = [
  'bgp',
@@ -527,8 +554,8 @@ def _reset_failed_services():
  'sflow',
  'restapi'
  ]
- execute_systemctl(services_to_reset, SYSTEMCTL_ACTION_RESET_FAILED)
 
+ execute_systemctl(services_to_reset, SYSTEMCTL_ACTION_RESET_FAILED)
 
 
 def _restart_services():
@@ -548,6 +575,12 @@ def _restart_services():
  'restapi'
  ]
 
+ disable_services = _get_disabled_services_list()
+
+ for service in disable_services:
+ if service in services_to_restart:
+ services_to_restart.remove(service)
+
  if asic_type == 'mellanox' and 'pmon' in services_to_restart:
  services_to_restart.remove('pmon')