Merge branch 'netwatch-notify'

6 files changed, 37 insertions, 8 deletions

diff --git a/doc/netwatch-notify.md b/doc/netwatch-notify.md
index 557ae88..11371ff 100644
--- a/doc/netwatch-notify.md
+++ b/doc/netwatch-notify.md
@@ -8,8 +8,9 @@ Description
 
 This script sends notifications about host UP and DOWN events. In comparison
 to just netwatch (`/ tool netwatch`) and its `up-script` and `down-script`
-this script implements a simple state machine. Host down events are triggered
-only if the host is down for several checks to avoid false alerts.
+this script implements a simple state machine and dependency model. Host
+down events are triggered only if the host is down for several checks and
+optional parent host is not down to avoid false alerts.
 
 Requirements and installation
 -----------------------------
@@ -39,6 +40,15 @@ The count threshould (default is 5 checks) is configurable as well:
 
     / tool netwatch add comment="notify, hostname=example.com, count=10" host=104.18.144.11;
 
+If the host is behind another checked host add a dependency, this will
+suppress notification if the parent host is down:
+
+    / tool netwatch add comment="notify, hostname=gateway" host=93.184.216.1;
+    / tool netwatch add comment="notify, hostname=example.com, parent=gateway" host=93.184.216.34;
+
+Note that every configured parent in a chain increases the check count
+threshould by one.
+
 Also notification settings are required for e-mail and telegram.
 
 ---
diff --git a/global-config b/global-config
index 9bbbc29..591bdda 100644
--- a/global-config
+++ b/global-config
@@ -8,7 +8,7 @@
 
 # Make sure all configuration properties are up to date and this
 # value is in sync with value in script 'global-functions'!
-:global GlobalConfigVersion 36;
+:global GlobalConfigVersion 37;
 
 # This is used for DNS and backup file.
 :global Domain "example.com";
diff --git a/global-config-overlay b/global-config-overlay
index 2777519..a0c6361 100644
--- a/global-config-overlay
+++ b/global-config-overlay
@@ -9,7 +9,7 @@
 # Make sure all configuration properties are up to date and this
 # value is in sync with value in script 'global-functions'!
 # Comment or remove to disable change notifications.
-:global GlobalConfigVersion 36;
+:global GlobalConfigVersion 37;
 
 # Copy configuration from global-config here and modify it.
 
diff --git a/global-config.changes b/global-config.changes
index 85529eb..5c400a5 100644
--- a/global-config.changes
+++ b/global-config.changes
@@ -40,4 +40,5 @@
   34="Introduced script 'ospf-to-leds' to visualize OSPF instance state via LEDs.";
   35="Implemented visual feedback for 'mode-button' with configurable LED.";
   36="Added support for installing updates automatically if seen in neighbor list.";
+  37="Implemented simple dependency model in 'netwatch-notify'.";
 };
diff --git a/global-functions b/global-functions
index a4a3630..b0b27c2 100644
--- a/global-functions
+++ b/global-functions
@@ -8,7 +8,7 @@
 # https://git.eworm.de/cgit/routeros-scripts/about/
 
 # expected configuration version
-:global ExpectedConfigVersion 36;
+:global ExpectedConfigVersion 37;
 
 # global variables not to be changed by user
 :global GlobalFunctionsReady false;
diff --git a/netwatch-notify b/netwatch-notify
index 6c2a18c..9a12c5a 100644
--- a/netwatch-notify
+++ b/netwatch-notify
@@ -42,14 +42,31 @@
       }
     }
     :set ($Metric->"notified") false;
+    :set ($Metric->"parent") ($HostInfo->"parent");
     :set ($Metric->"since");
   } else={
     :set ($Metric->"count") ($Metric->"count" + 1);
+    :set ($Metric->"parent") ($HostInfo->"parent");
     :set ($Metric->"since") ($HostVal->"since");
+    :local Count [ $IfThenElse ([ :tonum ($HostInfo->"count") ] > 0) ($HostInfo->"count") 5 ];
+    :local Parent ($HostInfo->"parent");
+    :while ([ :len $Parent ] > 0) do={
+      :set Count ($Count + 1);
+      :set Parent ($NetwatchNotify->$Parent->"parent");
+    }
+    :set Parent ($HostInfo->"parent");
+    :local ParentNotified false;
+    :while ($ParentNotified = false && [ :len $Parent ] > 0) do={
+      :set ParentNotified [ $IfThenElse (($NetwatchNotify->$Parent->"notified") = true) true false ];
+      :if ($ParentNotified = false) do={
+        :set Parent ($NetwatchNotify->$Parent->"parent");
+      }
+    }
     $LogPrintExit info ("Host " . $HostName . " (" . $HostVal->"host" . ") is down for " . \
-      $Metric->"count" . " checks.") false;
-    :if ($Metric->"count" >= [ $IfThenElse ([ :typeof ($HostInfo->"count") ] != "nothing") ($HostInfo->"count") 5 ] && \
-         $Metric->"notified" != true) do={
+      $Metric->"count" . " checks, " . [ $IfThenElse ($ParentNotified = false) [ $IfThenElse \
+      ($Metric->"notified" = true) ("already notified.") ($Count - $Metric->"count" . " to go.") ] \
+      ("parent host " . $Parent . " is down.") ]) false;
+    :if ($ParentNotified = false && $Metric->"count" >= $Count && $Metric->"notified" != true) do={
       $SendNotification ([ $SymbolForNotification "cross-mark" ] . "Netwatch Notify: " . $HostName . " down") \
         ("Host " . $HostName . " (" . $HostVal->"host" . ") is down since " . $HostVal->"since" . ".");
       :set ($Metric->"notified") true;
@@ -62,5 +79,6 @@
   :set ($NetwatchNotify->$HostName) {
     "count"=($Metric->"count");
     "notified"=($Metric->"notified");
+    "parent"=($Metric->"parent");
     "since"=($Metric->"since") };
 }