upgrades: Enable backup/restore

Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

functional_tests/features/upgrades.feature

@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
-@essential @upgrades @system
+@essential @upgrades @system @backups
 Feature: Software Upgrades
   Configure automatic software upgrades
 
@@ -31,3 +31,11 @@ Scenario: Disable automatic upgrades
   Given automatic upgrades are enabled
   When I disable automatic upgrades
   Then automatic upgrades should be disabled
+
+Scenario: Backup and restore upgrades
+  When I enable automatic upgrades
+  And I create a backup of the upgrades app data
+  And I disable automatic upgrades
+  And I export the upgrades app data backup
+  And I restore the upgrades app data backup
+  Then automatic upgrades should be enabled

plinth/modules/upgrades/__init__.py

@@ -24,6 +24,8 @@ from plinth import service as service_module
 from plinth import actions
 from plinth.menu import main_menu
 
+from .manifest import backup
+
 version = 1
 
 is_essential = True

plinth/modules/upgrades/manifest.py

@@ -0,0 +1,27 @@
+#
+# This file is part of FreedomBox.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Application manifest for upgrades.
+"""
+
+from plinth.modules.backups.api import validate as validate_backup
+
+backup = validate_backup({
+    'config': {
+        'files': ['/etc/apt/apt.conf.d/20auto-upgrades']
+    }
+})