migration: T6007: convert all migration scripts to load as module

(cherry picked from commit 26740a8d583f64dc0a27b59dd4ae303056972c0b)

1 files changed, 17 insertions, 33 deletions

diff --git a/src/migration-scripts/system/20-to-21 b/src/migration-scripts/system/20-to-21
index 24e042ce2..71c283da6 100755..100644
--- a/src/migration-scripts/system/20-to-21
+++ b/src/migration-scripts/system/20-to-21
@@ -1,46 +1,30 @@
-#!/usr/bin/env python3
+# Copyright 2021-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2021-2024 VyOS maintainers and contributors
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
 #
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 or later as
-# published by the Free Software Foundation.
-#
-# This program is distributed in the hope that it will be useful,
+# This library is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
 #
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# You should have received a copy of the GNU Lesser General Public License
+# along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
 # T3795: merge "system name-servers-dhcp" into "system name-server"
 
-from sys import argv
 from vyos.configtree import ConfigTree
 
-if len(argv) < 2:
-    print("Must specify file name!")
-    exit(1)
-
-file_name = argv[1]
-with open(file_name, 'r') as f:
-    config_file = f.read()
-
 base = ['system', 'name-servers-dhcp']
-config = ConfigTree(config_file)
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
 
-for interface in config.return_values(base):
-    config.set(['system', 'name-server'], value=interface, replace=False)
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
 
-config.delete(base)
+    for interface in config.return_values(base):
+        config.set(['system', 'name-server'], value=interface, replace=False)
 
-try:
-    with open(file_name, 'w') as f:
-        f.write(config.to_string())
-except OSError as e:
-    print("Failed to save the modified config: {}".format(e))
-    exit(1)
+    config.delete(base)