Source code for duplicity.backends.par2backend

# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4; encoding:utf-8 -*-
# Copyright 2013 Germar Reitze <>
# This file is part of duplicity.
# Duplicity is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
# Duplicity is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with duplicity; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

import os
import re
from duplicity import backend
from duplicity.errors import BackendException
from duplicity import log
from duplicity import config
from duplicity import util

[docs]class Par2Backend(backend.Backend): u"""This backend wrap around other backends and create Par2 recovery files before the file and the Par2 files are transfered with the wrapped backend. If a received file is corrupt it will try to repair it on the fly. """
[docs] def __init__(self, parsed_url): backend.Backend.__init__(self, parsed_url) self.parsed_url = parsed_url try: self.redundancy = config.par2_redundancy except AttributeError: self.redundancy = 10 try: self.volumes = config.par2_volumes except AttributeError: self.volumes = 1 try: self.common_options = config.par2_options + u" -q -q" except AttributeError: self.common_options = u"-q -q" self.wrapped_backend = backend.get_backend_object(parsed_url.url_string) for attr in [u'_get', u'_put', u'_list', u'_delete', u'_delete_list', u'_query', u'_query_list', u'_retry_cleanup', u'_error_code', u'_move', u'_close']: if hasattr(self.wrapped_backend, attr): setattr(self, attr, getattr(self, attr[1:])) # always declare _delete_list support because _delete queries file # list for every call self._delete_list = self.delete_list
[docs] def transfer(self, method, source_path, remote_filename): u"""create Par2 files and transfer the given file and the Par2 files with the wrapped backend. Par2 must run on the real filename or it would restore the temp-filename later on. So first of all create a tempdir and symlink the soure_path with remote_filename into this. """ par2temp = source_path.get_temp_in_same_dir() par2temp.mkdir() source_symlink = par2temp.append(remote_filename) source_target = source_path.get_canonical() if not os.path.isabs(source_target): source_target = os.path.join(util.fsencode(os.getcwd()), source_target) os.symlink(source_target, source_symlink.get_canonical()) source_symlink.setdata() log.Info(u"Create Par2 recovery files") par2create = u'par2 c -r%d -n%d %s "%s"' % (self.redundancy, self.volumes, self.common_options, util.fsdecode(source_symlink.get_canonical())) returncode, out, err = self.subprocess_popen(par2create) if returncode: log.Warn(u"Failed to create par2 file with requested options, retrying with -n1") par2create = u'par2 c -r%d -n1 %s "%s"' % (self.redundancy, self.common_options, util.fsdecode(source_symlink.get_canonical())) returncode, out, err = self.subprocess_popen(par2create) if not returncode: log.Warn(u"Successfully created par2 file with -n1") source_symlink.delete() files_to_transfer = [] if not returncode: for file in par2temp.listdir(): files_to_transfer.append(par2temp.append(file)) else: log.Error(u"FAILED to create par2 file with returncode %d" % returncode) method(source_path, remote_filename) for file in files_to_transfer: method(file, file.get_filename()) par2temp.deltree()
[docs] def put(self, local, remote): self.transfer(self.wrapped_backend._put, local, remote)
[docs] def move(self, local, remote): self.transfer(self.wrapped_backend._move, local, remote)
[docs] def get(self, remote_filename, local_path): u"""transfer remote_filename and the related .par2 file into a temp-dir. remote_filename will be renamed into local_path before finishing. If "par2 verify" detect an error transfer the Par2-volumes into the temp-dir and try to repair. """ par2temp = local_path.get_temp_in_same_dir() par2temp.mkdir() local_path_temp = par2temp.append(remote_filename) self.wrapped_backend._get(remote_filename, local_path_temp) try: par2file = par2temp.append(remote_filename + b'.par2') self.wrapped_backend._get(par2file.get_filename(), par2file) par2verify = u'par2 v %s %s "%s"' % (self.common_options, util.fsdecode(par2file.get_canonical()), util.fsdecode(local_path_temp.get_canonical())) returncode, out, err = self.subprocess_popen(par2verify) if returncode: log.Warn(u"File is corrupt. Try to repair %s" % remote_filename) c = re.compile(u'%s\\.vol[\\d+]*\\.par2' % remote_filename.decode()) par2volumes = [f for f in self.wrapped_backend._list() if c.match(util.fsdecode(f))] for filename in par2volumes: file = par2temp.append(filename) self.wrapped_backend._get(filename, file) par2repair = u'par2 r %s %s "%s"' % (self.common_options, util.fsdecode(par2file.get_canonical()), util.fsdecode(local_path_temp.get_canonical())) returncode, out, err = self.subprocess_popen(par2repair) if returncode: log.Error(u"Failed to repair %s" % remote_filename) else: log.Warn(u"Repair successful %s" % remote_filename) except BackendException: # par2 file not available pass finally: local_path_temp.rename(local_path) par2temp.deltree()
[docs] def delete(self, filename): u"""delete given filename and its .par2 files """ self.wrapped_backend._delete(filename) remote_list = self.unfiltered_list() c = re.compile(u'%s(?:\\.vol[\\d+]*)?\\.par2' % util.fsdecode(filename)) for remote_filename in remote_list: if c.match(util.fsdecode(remote_filename)): self.wrapped_backend._delete(util.fsencode(remote_filename))
[docs] def delete_list(self, filename_list): u"""delete given filename_list and all .par2 files that belong to them """ remote_list = self.unfiltered_list() for filename in filename_list[:]: c = re.compile(u'%s(?:\\.vol[\\d+]*)?\\.par2' % util.fsdecode(filename)) for remote_filename in remote_list: if c.match(util.fsdecode(remote_filename)): # insert here to make sure par2 files will be removed first filename_list.insert(0, remote_filename) if hasattr(self.wrapped_backend, u'_delete_list'): return self.wrapped_backend._delete_list(filename_list) else: for filename in filename_list: self.wrapped_backend._delete(filename)
[docs] def list(self): u""" Return list of filenames (byte strings) present in backend Files ending with ".par2" will be excluded from the list. """ remote_list = self.wrapped_backend._list() c = re.compile(u'(?!.*\\.par2$)') filtered_list = [] for filename in remote_list: if c.match(util.fsdecode(filename)): filtered_list.append(filename) return filtered_list
[docs] def unfiltered_list(self): return self.wrapped_backend._list()
[docs] def retry_cleanup(self): self.wrapped_backend._retry_cleanup()
[docs] def error_code(self, operation, e): return self.wrapped_backend._error_code(operation, e)
[docs] def query(self, filename): return self.wrapped_backend._query(filename)
[docs] def query_list(self, filename_list): return self.wrapped_backend._query(filename_list)
[docs] def close(self): self.wrapped_backend._close()
backend.register_backend_prefix(u'par2', Par2Backend)