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

8 files changed, 287 insertions, 456 deletions

diff --git a/src/migration-scripts/policy/0-to-1 b/src/migration-scripts/policy/0-to-1
index 8508b734a..837946c37 100755..100644
--- a/src/migration-scripts/policy/0-to-1
+++ b/src/migration-scripts/policy/0-to-1
@@ -1,65 +1,43 @@
-#!/usr/bin/env python3
+# Copyright 2021-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2021 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/>.
 
 # T3631: route-map: migrate "set extcommunity-rt" and "set extcommunity-soo"
 #        to "set extcommunity rt|soo" to match FRR syntax
 
-
-from sys import argv
-from sys import exit
-
 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 = ['policy', 'route-map']
-config = ConfigTree(config_file)
-
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
-
 
-for route_map in config.list_nodes(base):
-    if not config.exists(base + [route_map, 'rule']):
-        continue
-    for rule in config.list_nodes(base + [route_map, 'rule']):
-        base_rule = base + [route_map, 'rule', rule]
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
 
-        if config.exists(base_rule + ['set', 'extcommunity-rt']):
-            tmp = config.return_value(base_rule + ['set', 'extcommunity-rt'])
-            config.delete(base_rule + ['set', 'extcommunity-rt'])
-            config.set(base_rule + ['set', 'extcommunity', 'rt'], value=tmp)
+    for route_map in config.list_nodes(base):
+        if not config.exists(base + [route_map, 'rule']):
+            continue
+        for rule in config.list_nodes(base + [route_map, 'rule']):
+            base_rule = base + [route_map, 'rule', rule]
 
+            if config.exists(base_rule + ['set', 'extcommunity-rt']):
+                tmp = config.return_value(base_rule + ['set', 'extcommunity-rt'])
+                config.delete(base_rule + ['set', 'extcommunity-rt'])
+                config.set(base_rule + ['set', 'extcommunity', 'rt'], value=tmp)
 
-        if config.exists(base_rule + ['set', 'extcommunity-soo']):
-            tmp = config.return_value(base_rule + ['set', 'extcommunity-soo'])
-            config.delete(base_rule + ['set', 'extcommunity-soo'])
-            config.set(base_rule + ['set', 'extcommunity', 'soo'], value=tmp)
 
-try:
-    with open(file_name, 'w') as f:
-        f.write(config.to_string())
-except OSError as e:
-    print(f'Failed to save the modified config: {e}')
-    exit(1)
+            if config.exists(base_rule + ['set', 'extcommunity-soo']):
+                tmp = config.return_value(base_rule + ['set', 'extcommunity-soo'])
+                config.delete(base_rule + ['set', 'extcommunity-soo'])
+                config.set(base_rule + ['set', 'extcommunity', 'soo'], value=tmp)
diff --git a/src/migration-scripts/policy/1-to-2 b/src/migration-scripts/policy/1-to-2
index c7a983bba..ba3e48db0 100755..100644
--- a/src/migration-scripts/policy/1-to-2
+++ b/src/migration-scripts/policy/1-to-2
@@ -1,86 +1,67 @@
-#!/usr/bin/env python3
+# Copyright 2022-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2022 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/>.
 
 # T4170: rename "policy ipv6-route" to "policy route6" to match common
 #        IPv4/IPv6 schema
 # T4178: Update tcp flags to use multi value node
 
-from sys import argv
-from sys import exit
-
 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 = ['policy']
-config = ConfigTree(config_file)
 
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
 
-if config.exists(base + ['ipv6-route']):
-    config.rename(base + ['ipv6-route'],'route6')
-    config.set_tag(['policy', 'route6'])
+    if config.exists(base + ['ipv6-route']):
+        config.rename(base + ['ipv6-route'],'route6')
+        config.set_tag(['policy', 'route6'])
 
-for route in ['route', 'route6']:
-    if config.exists(base + [route]):
-        for name in config.list_nodes(base + [route]):
-            if config.exists(base + [route, name, 'rule']):
-                for rule in config.list_nodes(base + [route, name, 'rule']):
-                    rule_tcp_flags = base + [route, name, 'rule', rule, 'tcp', 'flags']
+    for route in ['route', 'route6']:
+        if config.exists(base + [route]):
+            for name in config.list_nodes(base + [route]):
+                if config.exists(base + [route, name, 'rule']):
+                    for rule in config.list_nodes(base + [route, name, 'rule']):
+                        rule_tcp_flags = base + [route, name, 'rule', rule, 'tcp', 'flags']
 
-                    if config.exists(rule_tcp_flags):
-                        tmp = config.return_value(rule_tcp_flags)
-                        config.delete(rule_tcp_flags)
-                        for flag in tmp.split(","):
+                        if config.exists(rule_tcp_flags):
+                            tmp = config.return_value(rule_tcp_flags)
+                            config.delete(rule_tcp_flags)
                             for flag in tmp.split(","):
-                                if flag[0] == '!':
-                                    config.set(rule_tcp_flags + ['not', flag[1:].lower()])
-                                else:
-                                    config.set(rule_tcp_flags + [flag.lower()])
+                                for flag in tmp.split(","):
+                                    if flag[0] == '!':
+                                        config.set(rule_tcp_flags + ['not', flag[1:].lower()])
+                                    else:
+                                        config.set(rule_tcp_flags + [flag.lower()])
 
-if config.exists(['interfaces']):
-    def if_policy_rename(config, path):
-        if config.exists(path + ['policy', 'ipv6-route']):
-            config.rename(path + ['policy', 'ipv6-route'], 'route6')
+    if config.exists(['interfaces']):
+        def if_policy_rename(config, path):
+            if config.exists(path + ['policy', 'ipv6-route']):
+                config.rename(path + ['policy', 'ipv6-route'], 'route6')
 
-    for if_type in config.list_nodes(['interfaces']):
-        for ifname in config.list_nodes(['interfaces', if_type]):
-            if_path = ['interfaces', if_type, ifname]
-            if_policy_rename(config, if_path)
+        for if_type in config.list_nodes(['interfaces']):
+            for ifname in config.list_nodes(['interfaces', if_type]):
+                if_path = ['interfaces', if_type, ifname]
+                if_policy_rename(config, if_path)
 
-        for vif_type in ['vif', 'vif-s']:
-            if config.exists(if_path + [vif_type]):
-                for vifname in config.list_nodes(if_path + [vif_type]):
-                    if_policy_rename(config, if_path + [vif_type, vifname])
+            for vif_type in ['vif', 'vif-s']:
+                if config.exists(if_path + [vif_type]):
+                    for vifname in config.list_nodes(if_path + [vif_type]):
+                        if_policy_rename(config, if_path + [vif_type, vifname])
 
-                    if config.exists(if_path + [vif_type, vifname, 'vif-c']):
-                        for vifcname in config.list_nodes(if_path + [vif_type, vifname, 'vif-c']):
-                            if_policy_rename(config, if_path + [vif_type, vifname, 'vif-c', vifcname])
-try:
-    with open(file_name, 'w') as f:
-        f.write(config.to_string())
-except OSError as e:
-    print(f'Failed to save the modified config: {e}')
-    exit(1)
+                        if config.exists(if_path + [vif_type, vifname, 'vif-c']):
+                            for vifcname in config.list_nodes(if_path + [vif_type, vifname, 'vif-c']):
+                                if_policy_rename(config, if_path + [vif_type, vifname, 'vif-c', vifcname])
diff --git a/src/migration-scripts/policy/2-to-3 b/src/migration-scripts/policy/2-to-3
index 8a62c8e6f..399a55387 100755..100644
--- a/src/migration-scripts/policy/2-to-3
+++ b/src/migration-scripts/policy/2-to-3
@@ -1,58 +1,38 @@
-#!/usr/bin/env python3
+# Copyright 2022-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2022 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/>.
 
 # T3976: change cli
 #     from: set policy route-map FOO rule 10 match ipv6 nexthop 'h:h:h:h:h:h:h:h'
 #       to: set policy route-map FOO rule 10 match ipv6 nexthop address 'h:h:h:h:h:h:h:h'
 
-from sys import argv
-from sys import exit
-
 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 = ['policy', 'route-map']
-config = ConfigTree(config_file)
-
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
-
-for route_map in config.list_nodes(base):
-    if not config.exists(base + [route_map, 'rule']):
-        continue
-    for rule in config.list_nodes(base + [route_map, 'rule']):
-        base_rule = base + [route_map, 'rule', rule]
-
-        if config.exists(base_rule + ['match', 'ipv6', 'nexthop']):
-            tmp = config.return_value(base_rule + ['match', 'ipv6', 'nexthop'])
-            config.delete(base_rule + ['match', 'ipv6', 'nexthop'])
-            config.set(base_rule + ['match', 'ipv6', 'nexthop', 'address'], value=tmp)
 
-try:
-    with open(file_name, 'w') as f:
-        f.write(config.to_string())
-except OSError as e:
-    print(f'Failed to save the modified config: {e}')
-    exit(1)
\ No newline at end of file
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
+
+    for route_map in config.list_nodes(base):
+        if not config.exists(base + [route_map, 'rule']):
+            continue
+        for rule in config.list_nodes(base + [route_map, 'rule']):
+            base_rule = base + [route_map, 'rule', rule]
+
+            if config.exists(base_rule + ['match', 'ipv6', 'nexthop']):
+                tmp = config.return_value(base_rule + ['match', 'ipv6', 'nexthop'])
+                config.delete(base_rule + ['match', 'ipv6', 'nexthop'])
+                config.set(base_rule + ['match', 'ipv6', 'nexthop', 'address'], value=tmp)
diff --git a/src/migration-scripts/policy/3-to-4 b/src/migration-scripts/policy/3-to-4
index 476fa3af2..5d4959def 100755..100644
--- a/src/migration-scripts/policy/3-to-4
+++ b/src/migration-scripts/policy/3-to-4
@@ -1,18 +1,17 @@
-#!/usr/bin/env python3
+# Copyright 2022-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2022 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/>.
 
 # T4660: change cli
 #     from: set policy route-map FOO rule 10 set community 'TEXT'
@@ -33,9 +32,6 @@
 #     Multiple value
 #     to: set policy route-map FOO rule 10 set extcommunity [rt|soo] <community>
 
-from sys import argv
-from sys import exit
-
 from vyos.configtree import ConfigTree
 
 
@@ -96,67 +92,52 @@ def extcommunity_migrate(config: ConfigTree, rule: list[str]) -> None:
             config.set(rule + ['soo'], value=community, replace=False)
 
 
-if len(argv) < 2:
-    print("Must specify file name!")
-    exit(1)
-
-file_name: str = argv[1]
-
-with open(file_name, 'r') as f:
-    config_file = f.read()
-
 base: list[str] = ['policy', 'route-map']
-config = ConfigTree(config_file)
-
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
-
-for route_map in config.list_nodes(base):
-    if not config.exists(base + [route_map, 'rule']):
-        continue
-    for rule in config.list_nodes(base + [route_map, 'rule']):
-        base_rule: list[str] = base + [route_map, 'rule', rule, 'set']
-
-        # IF additive presents in coummunity then comm-list is redundant
-        isAdditive: bool = True
-        #### Change Set community ########
-        if config.exists(base_rule + ['community']):
-            isAdditive = community_migrate(config,
-                                           base_rule + ['community'])
-
-        #### Change Set community-list delete migrate ########
-        if config.exists(base_rule + ['comm-list', 'comm-list']):
-            if isAdditive:
-                tmp = config.return_value(
-                    base_rule + ['comm-list', 'comm-list'])
-                config.delete(base_rule + ['comm-list'])
-                config.set(base_rule + ['community', 'delete'], value=tmp)
-            else:
-                config.delete(base_rule + ['comm-list'])
-
-        isAdditive = False
-        #### Change Set large-community ########
-        if config.exists(base_rule + ['large-community']):
-            isAdditive = community_migrate(config,
-                                           base_rule + ['large-community'])
-
-        #### Change Set large-community delete by List ########
-        if config.exists(base_rule + ['large-comm-list-delete']):
-            if isAdditive:
-                tmp = config.return_value(
-                    base_rule + ['large-comm-list-delete'])
-                config.delete(base_rule + ['large-comm-list-delete'])
-                config.set(base_rule + ['large-community', 'delete'],
-                           value=tmp)
-            else:
-                config.delete(base_rule + ['large-comm-list-delete'])
-
-        #### Change Set extcommunity ########
-        extcommunity_migrate(config, base_rule + ['extcommunity'])
-try:
-    with open(file_name, 'w') as f:
-        f.write(config.to_string())
-except OSError as e:
-    print(f'Failed to save the modified config: {e}')
-    exit(1)
+
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
+
+    for route_map in config.list_nodes(base):
+        if not config.exists(base + [route_map, 'rule']):
+            continue
+        for rule in config.list_nodes(base + [route_map, 'rule']):
+            base_rule: list[str] = base + [route_map, 'rule', rule, 'set']
+
+            # IF additive presents in coummunity then comm-list is redundant
+            isAdditive: bool = True
+            #### Change Set community ########
+            if config.exists(base_rule + ['community']):
+                isAdditive = community_migrate(config,
+                                               base_rule + ['community'])
+
+            #### Change Set community-list delete migrate ########
+            if config.exists(base_rule + ['comm-list', 'comm-list']):
+                if isAdditive:
+                    tmp = config.return_value(
+                        base_rule + ['comm-list', 'comm-list'])
+                    config.delete(base_rule + ['comm-list'])
+                    config.set(base_rule + ['community', 'delete'], value=tmp)
+                else:
+                    config.delete(base_rule + ['comm-list'])
+
+            isAdditive = False
+            #### Change Set large-community ########
+            if config.exists(base_rule + ['large-community']):
+                isAdditive = community_migrate(config,
+                                               base_rule + ['large-community'])
+
+            #### Change Set large-community delete by List ########
+            if config.exists(base_rule + ['large-comm-list-delete']):
+                if isAdditive:
+                    tmp = config.return_value(
+                        base_rule + ['large-comm-list-delete'])
+                    config.delete(base_rule + ['large-comm-list-delete'])
+                    config.set(base_rule + ['large-community', 'delete'],
+                               value=tmp)
+                else:
+                    config.delete(base_rule + ['large-comm-list-delete'])
+
+            #### Change Set extcommunity ########
+            extcommunity_migrate(config, base_rule + ['extcommunity'])
diff --git a/src/migration-scripts/policy/4-to-5 b/src/migration-scripts/policy/4-to-5
index 738850f67..0ecfdfd5e 100755..100644
--- a/src/migration-scripts/policy/4-to-5
+++ b/src/migration-scripts/policy/4-to-5
@@ -1,39 +1,24 @@
-#!/usr/bin/env python3
+# Copyright 2022-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2022-2024 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/>.
 
 # T2199: Migrate interface policy nodes to policy route <name> interface <ifname>
 
-from sys import argv
-from sys import exit
-
 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()
-
 base4 = ['policy', 'route']
 base6 = ['policy', 'route6']
-config = ConfigTree(config_file)
-
 
 def delete_orphaned_interface_policy(config, iftype, ifname, vif=None, vifs=None, vifc=None):
     """Delete unexpected policy on interfaces in cases when
@@ -55,35 +40,6 @@ def delete_orphaned_interface_policy(config, iftype, ifname, vif=None, vifs=None
 
     config.delete(if_path + ['policy'])
 
-
-if not config.exists(base4) and not config.exists(base6):
-    # Delete orphaned nodes on interfaces T5941
-    for iftype in config.list_nodes(['interfaces']):
-        for ifname in config.list_nodes(['interfaces', iftype]):
-            delete_orphaned_interface_policy(config, iftype, ifname)
-
-            if config.exists(['interfaces', iftype, ifname, 'vif']):
-                for vif in config.list_nodes(['interfaces', iftype, ifname, 'vif']):
-                    delete_orphaned_interface_policy(config, iftype, ifname, vif=vif)
-
-            if config.exists(['interfaces', iftype, ifname, 'vif-s']):
-                for vifs in config.list_nodes(['interfaces', iftype, ifname, 'vif-s']):
-                    delete_orphaned_interface_policy(config, iftype, ifname, vifs=vifs)
-
-                    if config.exists(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
-                        for vifc in config.list_nodes(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
-                            delete_orphaned_interface_policy(config, iftype, ifname, vifs=vifs, vifc=vifc)
-
-    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)
-
-    # Nothing to do
-    exit(0)
-
 def migrate_interface(config, iftype, ifname, vif=None, vifs=None, vifc=None):
     if_path = ['interfaces', iftype, ifname]
     ifname_full = ifname
@@ -111,25 +67,40 @@ def migrate_interface(config, iftype, ifname, vif=None, vifs=None, vifc=None):
 
     config.delete(if_path + ['policy'])
 
-for iftype in config.list_nodes(['interfaces']):
-    for ifname in config.list_nodes(['interfaces', iftype]):
-        migrate_interface(config, iftype, ifname)
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base4) and not config.exists(base6):
+        # Delete orphaned nodes on interfaces T5941
+        for iftype in config.list_nodes(['interfaces']):
+            for ifname in config.list_nodes(['interfaces', iftype]):
+                delete_orphaned_interface_policy(config, iftype, ifname)
+
+                if config.exists(['interfaces', iftype, ifname, 'vif']):
+                    for vif in config.list_nodes(['interfaces', iftype, ifname, 'vif']):
+                        delete_orphaned_interface_policy(config, iftype, ifname, vif=vif)
 
-        if config.exists(['interfaces', iftype, ifname, 'vif']):
-            for vif in config.list_nodes(['interfaces', iftype, ifname, 'vif']):
-                migrate_interface(config, iftype, ifname, vif=vif)
+                if config.exists(['interfaces', iftype, ifname, 'vif-s']):
+                    for vifs in config.list_nodes(['interfaces', iftype, ifname, 'vif-s']):
+                        delete_orphaned_interface_policy(config, iftype, ifname, vifs=vifs)
 
-        if config.exists(['interfaces', iftype, ifname, 'vif-s']):
-            for vifs in config.list_nodes(['interfaces', iftype, ifname, 'vif-s']):
-                migrate_interface(config, iftype, ifname, vifs=vifs)
+                        if config.exists(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
+                            for vifc in config.list_nodes(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
+                                delete_orphaned_interface_policy(config, iftype, ifname, vifs=vifs, vifc=vifc)
 
-                if config.exists(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
-                    for vifc in config.list_nodes(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
-                        migrate_interface(config, iftype, ifname, vifs=vifs, vifc=vifc)
+        # Nothing to do
+        return
+
+    for iftype in config.list_nodes(['interfaces']):
+        for ifname in config.list_nodes(['interfaces', iftype]):
+            migrate_interface(config, iftype, ifname)
 
-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)
+            if config.exists(['interfaces', iftype, ifname, 'vif']):
+                for vif in config.list_nodes(['interfaces', iftype, ifname, 'vif']):
+                    migrate_interface(config, iftype, ifname, vif=vif)
+
+            if config.exists(['interfaces', iftype, ifname, 'vif-s']):
+                for vifs in config.list_nodes(['interfaces', iftype, ifname, 'vif-s']):
+                    migrate_interface(config, iftype, ifname, vifs=vifs)
+
+                    if config.exists(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
+                        for vifc in config.list_nodes(['interfaces', iftype, ifname, 'vif-s', vifs, 'vif-c']):
+                            migrate_interface(config, iftype, ifname, vifs=vifs, vifc=vifc)
diff --git a/src/migration-scripts/policy/5-to-6 b/src/migration-scripts/policy/5-to-6
index 86287d578..acba0b4be 100755..100644
--- a/src/migration-scripts/policy/5-to-6
+++ b/src/migration-scripts/policy/5-to-6
@@ -1,62 +1,42 @@
-#!/usr/bin/env python3
+# Copyright 2023-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2023 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/>.
 
 # T5165: Migrate policy local-route rule <tag> destination|source
 
-from sys import argv
-from sys import exit
-
 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()
-
 base4 = ['policy', 'local-route']
 base6 = ['policy', 'local-route6']
-config = ConfigTree(config_file)
-
-if not config.exists(base4) and not config.exists(base6):
-    # Nothing to do
-    exit(0)
-
-# replace 'policy local-route{v6} rule <tag> destination|source <x.x.x.x>'
-#      => 'policy local-route{v6} rule <tag> destination|source address <x.x.x.x>'
-for base in [base4, base6]:
-    if config.exists(base + ['rule']):
-        for rule in config.list_nodes(base + ['rule']):
-            dst_path = base + ['rule', rule, 'destination']
-            src_path = base + ['rule', rule, 'source']
-            # Destination
-            if config.exists(dst_path):
-                for dst_addr in config.return_values(dst_path):
-                    config.set(dst_path + ['address'], value=dst_addr, replace=False)
-            # Source
-            if config.exists(src_path):
-                for src_addr in config.return_values(src_path):
-                    config.set(src_path + ['address'], value=src_addr, 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)
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base4) and not config.exists(base6):
+        # Nothing to do
+        return
+
+    # replace 'policy local-route{v6} rule <tag> destination|source <x.x.x.x>'
+    #      => 'policy local-route{v6} rule <tag> destination|source address <x.x.x.x>'
+    for base in [base4, base6]:
+        if config.exists(base + ['rule']):
+            for rule in config.list_nodes(base + ['rule']):
+                dst_path = base + ['rule', rule, 'destination']
+                src_path = base + ['rule', rule, 'source']
+                # Destination
+                if config.exists(dst_path):
+                    for dst_addr in config.return_values(dst_path):
+                        config.set(dst_path + ['address'], value=dst_addr, replace=False)
+                # Source
+                if config.exists(src_path):
+                    for src_addr in config.return_values(src_path):
+                        config.set(src_path + ['address'], value=src_addr, replace=False)
diff --git a/src/migration-scripts/policy/6-to-7 b/src/migration-scripts/policy/6-to-7
index cdefc6837..69aa703c5 100755..100644
--- a/src/migration-scripts/policy/6-to-7
+++ b/src/migration-scripts/policy/6-to-7
@@ -1,18 +1,17 @@
-#!/usr/bin/env python3
+# Copyright 2023-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2023-2024 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/>.
 
 # T5729: Switch to valueless whenever is possible.
 # From
@@ -22,55 +21,36 @@
     # set policy [route | route6] ... rule <rule> log
     # Remove command if log=disable
 
-from sys import argv
-from sys import exit
-
 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 = ['policy']
-config = ConfigTree(config_file)
-
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
-
-for family in ['route', 'route6']:
-    if config.exists(base + [family]):
-
-        for policy_name in config.list_nodes(base + [family]):
-            if config.exists(base + [family, policy_name, 'rule']):
-                for rule in config.list_nodes(base + [family, policy_name, 'rule']):
-                    # Log
-                    if config.exists(base + [family, policy_name, 'rule', rule, 'log']):
-                        log_value = config.return_value(base + [family, policy_name, 'rule', rule, 'log'])
-                        config.delete(base + [family, policy_name, 'rule', rule, 'log'])
-                        if log_value == 'enable':
-                            config.set(base + [family, policy_name, 'rule', rule, 'log'])
-                    # State
-                    if config.exists(base + [family, policy_name, 'rule', rule, 'state']):
-                        flag_enable = 'False'
-                        for state in ['established', 'invalid', 'new', 'related']:
-                            if config.exists(base + [family, policy_name, 'rule', rule, 'state', state]):
-                                state_value = config.return_value(base + [family, policy_name, 'rule', rule, 'state', state])
-                                config.delete(base + [family, policy_name, 'rule', rule, 'state', state])
-                                if state_value == 'enable':
-                                    config.set(base + [family, policy_name, 'rule', rule, 'state'], value=state, replace=False)
-                                    flag_enable = 'True'
-                        if flag_enable == 'False':
-                            config.delete(base + [family, policy_name, 'rule', rule, 'state'])
 
-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)
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
+
+    for family in ['route', 'route6']:
+        if config.exists(base + [family]):
+
+            for policy_name in config.list_nodes(base + [family]):
+                if config.exists(base + [family, policy_name, 'rule']):
+                    for rule in config.list_nodes(base + [family, policy_name, 'rule']):
+                        # Log
+                        if config.exists(base + [family, policy_name, 'rule', rule, 'log']):
+                            log_value = config.return_value(base + [family, policy_name, 'rule', rule, 'log'])
+                            config.delete(base + [family, policy_name, 'rule', rule, 'log'])
+                            if log_value == 'enable':
+                                config.set(base + [family, policy_name, 'rule', rule, 'log'])
+                        # State
+                        if config.exists(base + [family, policy_name, 'rule', rule, 'state']):
+                            flag_enable = 'False'
+                            for state in ['established', 'invalid', 'new', 'related']:
+                                if config.exists(base + [family, policy_name, 'rule', rule, 'state', state]):
+                                    state_value = config.return_value(base + [family, policy_name, 'rule', rule, 'state', state])
+                                    config.delete(base + [family, policy_name, 'rule', rule, 'state', state])
+                                    if state_value == 'enable':
+                                        config.set(base + [family, policy_name, 'rule', rule, 'state'], value=state, replace=False)
+                                        flag_enable = 'True'
+                            if flag_enable == 'False':
+                                config.delete(base + [family, policy_name, 'rule', rule, 'state'])
diff --git a/src/migration-scripts/policy/7-to-8 b/src/migration-scripts/policy/7-to-8
index 73eece1a6..a887f37fe 100755..100644
--- a/src/migration-scripts/policy/7-to-8
+++ b/src/migration-scripts/policy/7-to-8
@@ -1,18 +1,17 @@
-#!/usr/bin/env python3
+# Copyright 2023-2024 VyOS maintainers and contributors <maintainers@vyos.io>
 #
-# Copyright (C) 2023 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/>.
 
 # T5834: Rename 'enable-default-log' to 'default-log'
 # From
@@ -20,37 +19,18 @@
 # To
     # set policy [route | route 6] <route> default-log
 
-from sys import argv
-from sys import exit
-
 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 = ['policy']
-config = ConfigTree(config_file)
-
-if not config.exists(base):
-    # Nothing to do
-    exit(0)
 
-for family in ['route', 'route6']:
-    if config.exists(base + [family]):
+def migrate(config: ConfigTree) -> None:
+    if not config.exists(base):
+        # Nothing to do
+        return
 
-        for policy_name in config.list_nodes(base + [family]):
-            if config.exists(base + [family, policy_name, 'enable-default-log']):
-                config.rename(base + [family, policy_name, 'enable-default-log'], 'default-log')
+    for family in ['route', 'route6']:
+        if config.exists(base + [family]):
 
-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)
+            for policy_name in config.list_nodes(base + [family]):
+                if config.exists(base + [family, policy_name, 'enable-default-log']):
+                    config.rename(base + [family, policy_name, 'enable-default-log'], 'default-log')