Initial commit (unfinished) to address #1243.

borgmatic/actions/diff.py

@@ -0,0 +1,53 @@
+import logging
+
+import borgmatic.actions.pattern
+import borgmatic.borg.pattern
+import borgmatic.borg.diff
+
+logger = logging.getLogger(__name__)
+
+
+
+def run_diff(
+    repository,
+    config,
+    local_borg_version,
+    diff_arguments,
+    global_arguments,
+    local_path,
+    remote_path,
+):
+    '''
+    Run the "diff" action for the given repository.
+    '''
+
+    # Collect and process patterns.
+    processed_patterns = borgmatic.actions.pattern.process_patterns(
+        (
+            *borgmatic.actions.pattern.collect_patterns(config),
+        ),
+        config,
+        borgmatic.config.paths.get_working_directory(config),
+    )
+
+    archive = borgmatic.borg.repo_list.resolve_archive_name(
+        repository['path'],
+        diff_arguments.archive,
+        config,
+        local_borg_version,
+        global_arguments,
+        local_path,
+        remote_path,
+    )
+
+    borgmatic.borg.diff.diff(
+        repository['path'],
+        archive,
+        config,
+        local_borg_version,
+        diff_arguments,
+        global_arguments,
+        local_path=local_path,
+        remote_path=remote_path,
+        patterns=processed_patterns,
+    )

borgmatic/borg/diff.py

@@ -0,0 +1,88 @@
+import logging
+import shlex
+
+import borgmatic.borg.environment
+import borgmatic.borg.feature
+import borgmatic.config.paths
+import borgmatic.execute
+from borgmatic.borg import flags
+from borgmatic.borg.pattern import write_patterns_file
+
+logger = logging.getLogger(__name__)
+
+
+def diff(
+    repository,
+    archive,
+    config,
+    local_borg_version,
+    diff_arguments,
+    global_arguments,
+    local_path,
+    remote_path=None,
+    patterns=None,
+):
+    '''
+    Given a local or remote repository path, an archive name, a configuration dict, the local Borg
+    version string, an argparse.Namespace of diff arguments, an argparse.Namespace of global
+    arguments, optional local and remote Borg paths, executes the diff command with the given
+    arguments.
+    '''
+    lock_wait = config.get('lock_wait', None)
+    exclude_flags = flags.make_exclude_flags(config)
+    extra_borg_options = config.get('extra_borg_options', {}).get('diff', '')
+
+    # Write patterns to a temporary file and use that file with --patterns-from.
+    patterns_file = write_patterns_file(
+        patterns,
+        borgmatic.config.paths.get_working_directory(config),
+    )
+
+    diff_command = (
+        (local_path, 'diff')
+        + (('--remote-path', remote_path) if remote_path else ())
+        + ('--log-json',)
+        + (('--lock-wait', str(lock_wait)) if lock_wait is not None else ())
+        + (('--info',) if logger.getEffectiveLevel() == logging.INFO else ())
+        + (('--debug', '--show-rc') if logger.isEnabledFor(logging.DEBUG) else ())
+        + (('--patterns-from', patterns_file.name) if patterns_file else ())
+        + (
+            (
+                '--list',
+                '--filter',
+                flags.make_list_filter_flags(local_borg_version, global_arguments.dry_run),
+            )
+            if config.get('list_details')
+            else ()
+        )
+        + exclude_flags
+        + (tuple(shlex.split(extra_borg_options)) if extra_borg_options else ())
+        + (
+            (
+                flags.make_repository_flags(repository, local_borg_version)
+                + flags.make_match_archives_flags(
+                    archive or config.get('match_archives'),
+                    config.get('archive_name_format'),
+                    local_borg_version,
+                )
+            )
+            if borgmatic.borg.feature.available(
+                borgmatic.borg.feature.Feature.SEPARATE_REPOSITORY_ARCHIVE,
+                local_borg_version,
+            )
+            else (
+                flags.make_repository_archive_flags(repository, archive, local_borg_version)
+                if archive
+                else flags.make_repository_flags(repository, local_borg_version)
+            )
+        )
+    )
+
+    borgmatic.execute.execute_command(
+        full_command=diff_command,
+        output_log_level=logging.INFO,
+        environment=borgmatic.borg.environment.make_environment(config),
+        working_directory=borgmatic.config.paths.get_working_directory(config),
+        borg_local_path=local_path,
+        borg_exit_codes=config.get('borg_exit_codes'),
+    )

borgmatic/commands/arguments.py

@@ -33,6 +33,7 @@ ACTION_ALIASES = {
     'key': [],
     'borg': [],
     'recreate': [],
+    'diff': [],
 }
 
 
@@ -1970,6 +1971,23 @@ def make_parsers(schema, unparsed_arguments):  # noqa: PLR0915
         help='Show this help message and exit',
     )
 
+    diff_parser = action_parsers.add_parser(
+        'diff',
+        aliases=ACTION_ALIASES['diff'],
+        help='This command finds differences (file contents, user/group/mode) between archives',
+        description='This command finds differences (file contents, user/group/mode) between archives',
+        add_help=False,
+    )
+    diff_group = diff_parser.add_argument_group('diff arguments')
+    diff_group.add_argument(
+        '--repository',
+        help='Path of repository containing archive to diff, defaults to the configured repository if there is only one, quoted globs supported',
+    )
+    diff_group.add_argument(
+        '--archive',
+        help='Archive name, hash, or series to diff, defaults to all archives in the repository (if specified)',
+    )
+
     borg_parser = action_parsers.add_parser(
         'borg',
         aliases=ACTION_ALIASES['borg'],

borgmatic/commands/borgmatic.py

@@ -20,6 +20,7 @@ import borgmatic.actions.config.generate
 import borgmatic.actions.config.validate
 import borgmatic.actions.create
 import borgmatic.actions.delete
+import borgmatic.actions.diff
 import borgmatic.actions.export_key
 import borgmatic.actions.export_tar
 import borgmatic.actions.extract
@@ -622,6 +623,16 @@ def run_actions(  # noqa: PLR0912, PLR0915
                         local_path,
                         remote_path,
                     )
+                elif action_name == 'diff':
+                    borgmatic.actions.diff.run_diff(
+                        repository,
+                        config,
+                        local_borg_version,
+                        action_arguments,
+                        global_arguments,
+                        local_path,
+                        remote_path,
+                    )
                 elif action_name == 'borg':
                     borgmatic.actions.borg.run_borg(
                         repository,