From 0360a0ef901659b7a63ba9fcdf70883b8f098e72 Mon Sep 17 00:00:00 2001
From: Christian Hesse <mail@eworm.de>
Date: Fri, 18 Dec 2020 17:50:37 +0100
Subject: global-functions: $ScriptInstallUpdate: implement migration mechanism

Reset $SentConfigChangesNotification and rerun $ScriptInstallUpdate
to test...

:set SentConfigChangesNotification
$ScriptInstallUpdate
---
 global-config         | 2 +-
 global-config-overlay | 2 +-
 global-config.changes | 6 ++++++
 global-functions      | 9 ++++++++-
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/global-config b/global-config
index c1f5ec5..379701a 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 40;
+:global GlobalConfigVersion 41;
 
 # This is used for DNS and backup file.
 :global Domain "example.com";
diff --git a/global-config-overlay b/global-config-overlay
index aa22167..a7cd500 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 40;
+:global GlobalConfigVersion 41;
 
 # Copy configuration from global-config here and modify it.
 
diff --git a/global-config.changes b/global-config.changes
index 3c06553..2d53160 100644
--- a/global-config.changes
+++ b/global-config.changes
@@ -44,4 +44,10 @@
   38="Imported new Let's Encrypt intermediate certificate 'R3'.";
   39="Added support for interface specific address list entries in 'ipv6-update'.";
   40="Made the certificate renewal time configurable.";
+  41="Implemented migration mechanism for script updates.";
+};
+
+# Migration steps to be applied on script updates
+:global GlobalConfigMigration {
+  41=":global SendNotification; \$SendNotification (\"Migration mechanism\") (\"Congratulations!\nSuccessfully tested the new migration mechanism.\");";
 };
diff --git a/global-functions b/global-functions
index 9ee2d00..e1a7d3d 100644
--- a/global-functions
+++ b/global-functions
@@ -8,7 +8,7 @@
 # https://git.eworm.de/cgit/routeros-scripts/about/
 
 # expected configuration version
-:global ExpectedConfigVersion 40;
+:global ExpectedConfigVersion 41;
 
 # global variables not to be changed by user
 :global GlobalFunctionsReady false;
@@ -659,6 +659,7 @@
   :if ($SentConfigChangesNotification!=$ExpectedConfigVersion && \
        $GlobalConfigVersion < $ExpectedConfigVersion) do={
     :global GlobalConfigChanges;
+    :global GlobalConfigMigration;
     :local ChangeLogCode;
     :local ConfigScript "global-config";
     :if ([ :len [ / system script find where name="global-config-overlay" ] ] > 0) do={
@@ -684,8 +685,14 @@
         :set NotificationMessage ($NotificationMessage . \
             "\n * " . $GlobalConfigChanges->[ :tostr $I ]);
         $LogPrintExit info ("Change: " . $GlobalConfigChanges->[ :tostr $I ]) false;
+        :local Migration ($GlobalConfigMigration->[ :tostr $I ]);
+        :if ([ :typeof $Migration ] = "str") do={
+          $LogPrintExit info ("Applying migration: " . $Migration) false;
+          [ :parse $Migration ];
+        }
       }
       :set GlobalConfigChanges;
+      :set GlobalConfigMigration;
     } on-error={
       $LogPrintExit warning ("Failed fetching changes!") false;
       :set NotificationMessage ($NotificationMessage . \
-- 
cgit v1.2.3-54-g00ecf