backups: Automatically install required apps before restore

Fixes #1460

Signed-off-by: Joseph Nuthalapati <njoseph@thoughtworks.com>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/backups/api.py

@@ -27,7 +27,7 @@ TODO:
 
 import logging
 
-from plinth import actions, action_utils, module_loader
+from plinth import actions, action_utils, module_loader, setup
 
 logger = logging.getLogger(__name__)
 
@@ -204,6 +204,7 @@ def restore_apps(restore_handler, app_names=None, create_subvolume=True,
         restore_root = subvolume['mount_path']
         subvolume = True
     else:
+        _install_apps_before_restore(apps)
         _lockdown_apps(apps, lockdown=True)
         original_state = _shutdown_services(apps)
         restore_root = '/'
@@ -220,6 +221,16 @@ def restore_apps(restore_handler, app_names=None, create_subvolume=True,
         _lockdown_apps(apps, lockdown=False)
 
 
+def _install_apps_before_restore(apps):
+    """Automatically install any applications from the backup archive
+    if they are not installed yet."""
+    modules_to_setup = []
+    for backup_app in apps:
+        if backup_app.app.setup_helper.get_state() == 'needs-setup':
+            modules_to_setup.append(backup_app.name)
+    setup.run_setup_on_modules(modules_to_setup)
+
+
 class BackupApp:
     """A application that can be backed up and its manifest."""
 
@@ -228,10 +239,6 @@ class BackupApp:
         self.name = name
         self.app = app
 
-        # Not installed
-        if app.setup_helper.get_state() == 'needs-setup':
-            raise TypeError
-
         # Has no backup related meta data
         try:
             self.manifest = app.backup

plinth/modules/backups/tests/test_api.py

@@ -110,7 +110,8 @@ class TestBackupProcesses(unittest.TestCase):
         backup_handler.assert_called_once()
 
     @staticmethod
-    def test_restore_apps():
+    @patch('plinth.modules.backups.api._install_apps_before_restore')
+    def test_restore_apps(mock_install):
         """Test that restore_handler is called."""
         restore_handler = MagicMock()
         api.restore_apps(restore_handler)