Add an option --use-rmdir to use rmdir instead of rm -R

This is useful when the backups are CephFS snapshots.
Those are usually located in a special hidden directory (normally `.snap`) and cannot be removed by rm -R
(because they're read-only) but they can be removed by calling rmdir directly on the non-empty directory.
For example a simple backup procedure could be :
* mount cephfs to /backup
* backup the system to /backup
* make a snapshot with `mkdir /backup/.snap/<date>`
* rotate snapshots with `rotate-backups --use-rmdir /backup/.snap/`

Author: ls-initiatives

README.rst

@@ -211,6 +211,7 @@ intended you have no right to complain ;-).
    remote system over SSH)."
    "``-n``, ``--dry-run``","Don't make any changes, just print what would be done. This makes it easy
    to evaluate the impact of a rotation scheme without losing any backups."
+   "``-D``, ``--use-rmdir``","Use ""rmdir"" to remove the backups (useful with CephFS snapshots for example)."
    "``-v``, ``--verbose``",Increase logging verbosity (can be repeated).
    "``-q``, ``--quiet``",Decrease logging verbosity (can be repeated).
    "``-h``, ``--help``",Show this message and exit.
@@ -359,8 +360,8 @@ Supported configuration options
   - If an include or exclude list is defined in the configuration file it
     overrides the include or exclude list given on the command line.
 
-- The ``prefer-recent``, ``strict`` and ``use-sudo`` options expect a boolean
-  value (``yes``, ``no``, ``true``, ``false``, ``1`` or ``0``).
+- The ``prefer-recent``, ``strict``, ``rmdir`` and ``use-sudo`` options expect a
+  boolean value (``yes``, ``no``, ``true``, ``false``, ``1`` or ``0``).
 
 - The ``ionice`` option expects one of the I/O scheduling class names ``idle``,
   ``best-effort`` or ``realtime``.

rotate_backups/__init__.py

@@ -197,7 +197,8 @@ def load_config_file(configuration_file=None, expand=True):
                        exclude_list=split(items.get('exclude-list', '')),
                        io_scheduling_class=items.get('ionice'),
                        strict=coerce_boolean(items.get('strict', 'yes')),
-                       prefer_recent=coerce_boolean(items.get('prefer-recent', 'no')))
+                       prefer_recent=coerce_boolean(items.get('prefer-recent', 'no')),
+                       rmdir=items.get('use-rmdir'))
         # Expand filename patterns?
         if expand and location.have_wildcards:
             logger.verbose("Expanding filename pattern %s on %s ..", location.directory, location.context)
@@ -241,8 +242,9 @@ def __init__(self, rotation_scheme, **options):
         :param rotation_scheme: Used to set :attr:`rotation_scheme`.
         :param options: Any keyword arguments are used to set the values of the
                         properties :attr:`config_file`, :attr:`dry_run`,
-                        :attr:`exclude_list`, :attr:`include_list`,
-                        :attr:`io_scheduling_class` and :attr:`strict`.
+                        :attr:`rmdir`, :attr:`exclude_list`,
+                        :attr:`include_list`, :attr:`io_scheduling_class` and
+                        :attr:`strict`.
         """
         options.update(rotation_scheme=rotation_scheme)
         super(RotateBackups, self).__init__(**options)
@@ -269,6 +271,18 @@ def dry_run(self):
         """
         return False
 
+    @mutable_property
+    def rmdir(self):
+        """
+        :data:`True` to use `rmdir` to remove the snapshots, :data:`False` to use `rm -r` (defaults to :data:`False`).
+
+        Normally the backups are removed one file at a file using the command `rm -r`.
+        Some file-systems are capable of removing a whole directory with the command `rmdir`,
+        even when the directory is not empty. For example, this is how CephFS snapshots are
+        removed.
+        """
+        return False
+
     @cached_property(writable=True)
     def exclude_list(self):
         """
@@ -467,11 +481,18 @@ class together to implement backup rotation with an easy to use Python
             else:
                 logger.info("Deleting %s ..", friendly_name)
                 if not self.dry_run:
-                    command = location.context.prepare(
-                        'rm', '-Rf', backup.pathname,
-                        group_by=(location.ssh_alias, location.mount_point),
-                        ionice=self.io_scheduling_class,
-                    )
+                    if not self.rmdir:
+                        command = location.context.prepare(
+                            'rm', '-Rf', backup.pathname,
+                            group_by=(location.ssh_alias, location.mount_point),
+                            ionice=self.io_scheduling_class,
+                        )
+                    else:
+                        command = location.context.prepare(
+                            'rmdir', backup.pathname,
+                            group_by=(location.ssh_alias, location.mount_point),
+                            ionice=self.io_scheduling_class,
+                        )
                     rotation_commands.append(command)
                     if not prepare:
                         timer = Timer()

rotate_backups/cli.py

@@ -154,6 +154,12 @@
     Don't make any changes, just print what would be done. This makes it easy
     to evaluate the impact of a rotation scheme without losing any backups.
 
+  -D, --use-rmdir
+
+    Remove backups by calling `rmdir' to directly remove the whole directory
+    instead of deleting each of the files in it. This works only with special
+    directories such as CephFS snapshot.
+
   -v, --verbose
 
     Increase logging verbosity (can be repeated).
@@ -202,10 +208,10 @@ def main():
     selected_locations = []
     # Parse the command line arguments.
     try:
-        options, arguments = getopt.getopt(sys.argv[1:], 'M:H:d:w:m:y:I:x:jpri:c:r:unvqh', [
+        options, arguments = getopt.getopt(sys.argv[1:], 'M:H:d:w:m:y:I:x:jpri:c:r:uDnvqh', [
             'minutely=', 'hourly=', 'daily=', 'weekly=', 'monthly=', 'yearly=',
             'include=', 'exclude=', 'parallel', 'prefer-recent', 'relaxed',
-            'ionice=', 'config=', 'use-sudo', 'dry-run', 'verbose', 'quiet',
+            'ionice=', 'config=', 'use-sudo', 'dry-run', 'use-rmdir', 'verbose', 'quiet',
             'help',
         ])
         for option, value in options:
@@ -241,6 +247,8 @@ def main():
             elif option in ('-n', '--dry-run'):
                 logger.info("Performing a dry run (because of %s option) ..", option)
                 kw['dry_run'] = True
+            elif option in ('-D', '--use-rmdir'):
+                kw['rmdir'] = True
             elif option in ('-v', '--verbose'):
                 coloredlogs.increase_verbosity()
             elif option in ('-q', '--quiet'):