global-config: support loading snippets

This adds support for loading snippets, which need a name starting with
"global-config-overlay.d/". This allows to split off configuration if
desired.

README.md

@@ -139,6 +139,11 @@ Save changes and exit with `Ctrl-o`.
 
 ![screenshot: edit global-config-overlay](README.d/07-edit-global-config-overlay.avif)
 
+Additionally creating configuration snippets is supported. The script name
+of these snippets has to start with `global-config-overlay.d/` to make them
+being loaded automatically. This allows to split off parts of the
+configuration.
+
 To apply your changes run `global-config`, which will automatically load
 the overlay as well:
 

global-config.rsc

@@ -250,3 +250,13 @@
 } on-error={
   :log error ("Loading configuration from overlay failed!");
 }
+
+# configuration overlay snippets
+:foreach Script in=[ /system/script/find where name ~ "^global-config-overlay.d/" ] do={
+  :do {
+    /system/script/run $Script;
+  } on-error={
+    :log error ("Loading configuration from overlay snippet " . \
+        [ /system/script/get $Script name ] . " failed!");
+  }
+}

global-functions.rsc

@@ -12,7 +12,7 @@
 :local ScriptName [ :jobname ];
 
 # expected configuration version
-:global ExpectedConfigVersion 121;
+:global ExpectedConfigVersion 122;
 
 # global variables not to be changed by user
 :global GlobalFunctionsReady false;

news-and-changes.rsc

@@ -46,6 +46,7 @@
   119="Added support for IPv6 to script 'fw-addr-lists'.";
   120="Implemented a workaround in 'backup-cloud'. Now script should no longer just crash, but send notification with error.";
   121="The 'wifiwave2' scripts are finally gone. Development continues with 'wifi' in RouterOS 7.13 and later.";
+  122="The global configuration was enhanced to support loading snippets. Configuration can be split off to scripts where name starts with 'global-config-overlay.d/'.";
 };
 
 # Migration steps to be applied on script updates