netwatch-notify: do not (yet) notify if parent is up recently

Monitoring a VPN (or similar) may be tricky: This used to send notifications
if the physical connection recovered, but the VPN and/or its routing did not
yet. Let's work around and send notification only if the parent is up
for at least three checks.

Author: eworm-de

netwatch-notify

@@ -128,6 +128,7 @@ $ScriptLock $0;
       :set ($Metric->"since") ($HostVal->"since");
       :local CountDown [ $IfThenElse ([ :tonum ($HostInfo->"count-down") ] > 0) ($HostInfo->"count-down") 5 ];
       :local Parent ($HostInfo->"parent");
+      :local ParentUp false;
       :while ([ :len $Parent ] > 0) do={
         :set CountDown ($CountDown + 1);
         :set Parent ($NetwatchNotify->$Parent->"parent");
@@ -137,6 +138,7 @@ $ScriptLock $0;
       :while ($ParentNotified = false && [ :len $Parent ] > 0) do={
         :set ParentNotified [ $IfThenElse (($NetwatchNotify->$Parent->"notified") = true) \
             true false ];
+        :set ParentUp ($NetwatchNotify->$Parent->"count-up");
         :if ($ParentNotified = false) do={
           :set Parent ($NetwatchNotify->$Parent->"parent");
         }
@@ -151,7 +153,7 @@ $ScriptLock $0;
         $NetwatchNotifyHook $Name $Type "pre-down" ($HostInfo->"pre-down-hook");
       }
       :if ($ParentNotified = false && $Metric->"count-down" >= $CountDown && \
-           $Metric->"notified" != true) do={
+           ($ParentUp = false || $ParentUp > 2) && $Metric->"notified" != true) do={
         :local Message ("The " . $Type . " '" . $Name . "' (" . $HostDetails . \
             ") is down since " . $HostVal->"since" . ".");
         :if ([ :typeof ($HostInfo->"down-hook") ] = "str") do={