Add flag to allow setting a shutdown grace period

cmd/nginx/flags.go

@@ -171,6 +171,8 @@ Takes the form "<host>:port". If not provided, no admission controller is starte
 		profilerPort = flags.Int("profiler-port", 10245, "Port to use for expose the ingress controller Go profiler when it is enabled.")
 
 		statusUpdateInterval = flags.Int("status-update-interval", status.UpdateInterval, "Time interval in seconds in which the status should check if an update is required. Default is 60 seconds")
+
+		shutdownGracePeriod = flags.Int("shutdown-grace-period", 0, "Seconds to wait after receiving the shutdown signal, before stopping the nginx process.")
 	)
 
 	flags.StringVar(&nginx.MaxmindMirror, "maxmind-mirror", "", `Maxmind mirror url (example: http://geoip.local/databases`)
@@ -281,6 +283,7 @@ https://blog.maxmind.com/2019/12/18/significant-changes-to-accessing-and-using-g
 		PublishService:         *publishSvc,
 		PublishStatusAddress:   *publishStatusAddress,
 		UpdateStatusOnShutdown: *updateStatusOnShutdown,
+		ShutdownGracePeriod:    *shutdownGracePeriod,
 		UseNodeInternalIP:      *useNodeInternalIP,
 		SyncRateLimit:          *syncRateLimit,
 		ListenPorts: &ngx_config.ListenPorts{