backups: Allow comments to be added to archives during backup

Tests performed:

- Schedules are able to store and retrieve comments properly. Information about
schedule backups stored in comments is extracted properly.

- Unit tests run.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/backups

@@ -13,6 +13,7 @@ import sys
 import tarfile
 
 from plinth.modules.backups import MANIFESTS_FOLDER
+from plinth.utils import Version
 
 TIMEOUT = 30
 
@@ -38,6 +39,9 @@ def parse_arguments():
                                            help='Create archive')
     create_archive.add_argument('--paths', help='Paths to include in archive',
                                 nargs='+')
+    create_archive.add_argument('--comment',
+                                help='Comment text to add to archive',
+                                default='')
 
     delete_archive = subparsers.add_parser('delete-archive',
                                            help='Delete archive')
@@ -112,13 +116,32 @@ def subcommand_info(arguments):
 
 def subcommand_list_repo(arguments):
     """List repository contents."""
-    run(['borg', 'list', '--json', arguments.path], arguments)
+    run(['borg', 'list', '--json', '--format="{comment}"', arguments.path],
+        arguments)
+
+
+def _get_borg_version(arugments):
+    """Return the version of borgbackup."""
+    process = run(['borg', '--version'], arugments, stdout=subprocess.PIPE)
+    return process.stdout.decode().split()[1]  # Example: "borg 1.1.9"
 
 
 def subcommand_create_archive(arguments):
     """Create archive."""
     paths = filter(os.path.exists, arguments.paths)
-    run(['borg', 'create', '--json', arguments.path] + list(paths), arguments)
+    command = ['borg', 'create', '--json']
+    if arguments.comment:
+        comment = arguments.comment
+        if Version(_get_borg_version(arguments)) < Version('1.1.10'):
+            # Undo any placeholder escape sequences in comments as this version
+            # of borg does not support placeholders. XXX: Drop this code when
+            # support for borg < 1.1.10 is dropped.
+            comment = comment.replace('{{', '{').replace('}}', '}')
+
+        command += ['--comment', comment]
+
+    command += [arguments.path] + list(paths)
+    run(command, arguments)
 
 
 def subcommand_delete_archive(arguments):

plinth/modules/backups/__init__.py

@@ -85,7 +85,11 @@ def _backup_handler(packet, encryption_passphrase=None):
 
     paths = packet.directories + packet.files
     paths.append(manifest_path)
-    arguments = ['create-archive', '--path', packet.path, '--paths'] + paths
+    arguments = ['create-archive', '--path', packet.path]
+    if packet.archive_comment:
+        arguments += ['--comment', packet.archive_comment]
+
+    arguments += ['--paths'] + paths
     input_data = ''
     if encryption_passphrase:
         input_data = json.dumps(

plinth/modules/backups/api.py

@@ -41,7 +41,8 @@ class BackupError:
 class Packet:
     """Information passed to a handlers for backup/restore operations."""
 
-    def __init__(self, operation, scope, root, components=None, path=None):
+    def __init__(self, operation, scope, root, components=None, path=None,
+                 archive_comment=None):
         """Initialize the packet.
 
         operation is either 'backup' or 'restore.
@@ -62,6 +63,7 @@ class Packet:
         self.root = root
         self.components = components
         self.path = path
+        self.archive_comment = archive_comment
         self.errors = []
 
         self.directories = []
@@ -105,8 +107,8 @@ def restore_full(restore_handler):
     _switch_to_subvolume(subvolume)
 
 
-def backup_apps(backup_handler, path, app_ids=None,
-                encryption_passphrase=None):
+def backup_apps(backup_handler, path, app_ids=None, encryption_passphrase=None,
+                archive_comment=None):
     """Backup data belonging to a set of applications."""
     if not app_ids:
         components = get_all_components_for_backup()
@@ -123,7 +125,8 @@ def backup_apps(backup_handler, path, app_ids=None,
         backup_root = '/'
         snapshotted = False
 
-    packet = Packet('backup', 'apps', backup_root, components, path)
+    packet = Packet('backup', 'apps', backup_root, components, path,
+                    archive_comment)
     _run_operation(backup_handler, packet,
                    encryption_passphrase=encryption_passphrase)
 

plinth/modules/backups/repository.py

@@ -166,12 +166,13 @@ class BaseBorgRepository(abc.ABC):
         return sorted(archives, key=lambda archive: archive['start'],
                       reverse=True)
 
-    def create_archive(self, archive_name, app_ids):
+    def create_archive(self, archive_name, app_ids, archive_comment=None):
         """Create a new archive in this repository with given name."""
         archive_path = self._get_archive_path(archive_name)
         passphrase = self.credentials.get('encryption_passphrase', None)
         api.backup_apps(_backup_handler, path=archive_path, app_ids=app_ids,
-                        encryption_passphrase=passphrase)
+                        encryption_passphrase=passphrase,
+                        archive_comment=archive_comment)
 
     def delete_archive(self, archive_name):
         """Delete an archive with given name from this repository."""

plinth/modules/backups/tests/test_api.py

@@ -63,11 +63,21 @@ def _get_test_app(name):
 class TestBackupProcesses:
     """Test cases for backup processes"""
 
+    @staticmethod
+    def test_packet_init():
+        """Test that packet is initialized properly."""
+        packet = api.Packet('backup', 'apps', '/', [])
+        assert packet.archive_comment is None
+        packet = api.Packet('backup', 'apps', '/', [],
+                            archive_comment='test comment')
+        assert packet.archive_comment == 'test comment'
+
     @staticmethod
     def test_packet_collected_files_directories():
         """Test that directories/files are collected from manifests."""
         components = [_get_backup_component('a'), _get_backup_component('b')]
-        packet = api.Packet('backup', 'apps', '/', components)
+        packet = api.Packet('backup', 'apps', '/', components,
+                            archive_comment='test comment')
         for component in components:
             for section in ['config', 'data', 'secrets']:
                 for directory in getattr(component, section)['directories']:

plinth/modules/backups/tests/test_backups.py

@@ -88,18 +88,21 @@ def test_create_export_delete_archive(data_directory, backup_directory):
     """
     repo_name = 'test_create_and_delete'
     archive_name = 'first_archive'
+    archive_comment = 'test_archive_comment'
     path = backup_directory / repo_name
 
     repository = BorgRepository(str(path))
     repository.initialize()
     archive_path = "::".join([str(path), archive_name])
     actions.superuser_run('backups', [
-        'create-archive', '--path', archive_path, '--paths',
+        'create-archive', '--path', archive_path, '--comment', archive_comment,
+        '--paths',
         str(data_directory)
     ])
 
     archive = repository.list_archives()[0]
     assert archive['name'] == archive_name
+    assert archive['comment'] == archive_comment
 
     repository.delete_archive(archive_name)
     content = repository.list_archives()