Add error message when system's ping fail

Author: babs

display.go

@@ -51,7 +51,9 @@ func (d *Display) Update() {
 	for _, wrapper := range d.pwh.ping_wrappers {
 		sb.WriteString(fmt.Sprintf(d.host_format_string, wrapper.Host()))
 		stats := wrapper.CalcStats(2 * 1e9)
-		if stats.last_seen_nano > 2*1e9 {
+		if stats.error_message != "" {
+			sb.WriteString(bold_red.Sprintf("❌ %v", stats.error_message))
+		} else if stats.last_seen_nano > 2*1e9 {
 			if stats.lastrecv == 0 {
 				sb.WriteString(bold_red.Sprintf("❌ never had reply"))
 			} else {

pinger_system.go

@@ -56,6 +56,7 @@ func (w *SystemPingWrapper) Start() {
 				w.stats.lastrtt_as_string = extracted[0][1] + extracted[0][2]
 			}
 		}
+		w.stats.error_message = fmt.Sprintf("%v exited code %v", w.cmd.String(), w.cmd.ProcessState.ExitCode())
 	}()
 	w.cmd.Start()
 }

pwstats.go

@@ -19,6 +19,7 @@ type PWStats struct {
 	has_ever_received  bool
 	startup_time       int64
 	transition_writer  *TransitionWriter
+	error_message      string
 	hrepr              string
 	iprepr             string
 }