Current File : //lib/python3/dist-packages/duplicity/backends/par2backend.py
# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4; encoding:utf-8 -*-
#
# Copyright 2013 Germar Reitze <germar.reitze@gmail.com>
#
# 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
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# 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 import config
from duplicity import log
from duplicity.errors import BackendException
class Par2Backend(backend.Backend):
"""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.
"""
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 = f"{config.par2_options} -q -q"
except AttributeError:
self.common_options = "-q -q"
self.wrapped_backend = backend.get_backend_object(parsed_url.url_string)
for attr in [
"_get",
"_put",
"_list",
"_delete",
"_delete_list",
"_query",
"_query_list",
"_retry_cleanup",
"_error_code",
"_move",
"_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
def transfer(self, method, source_path, remote_filename):
"""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(os.fsencode(os.getcwd()), source_target)
os.symlink(source_target, source_symlink.get_canonical())
source_symlink.setdata()
log.Info("Create Par2 recovery files")
par2create = (
f"par2 c -r{int(self.redundancy)} -n{int(self.volumes)} {self.common_options} "
f'"{os.fsdecode(source_symlink.get_canonical())}"'
)
returncode, out, err = self.subprocess_popen(par2create)
if returncode:
log.Warn("Failed to create par2 file with requested options, retrying with -n1")
par2create = (
f"par2 c -r{int(self.redundancy)} -n1 {self.common_options} "
f'"{os.fsdecode(source_symlink.get_canonical())}"'
)
returncode, out, err = self.subprocess_popen(par2create)
if not returncode:
log.Warn("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(f"FAILED to create par2 file with returncode {int(returncode)}")
method(source_path, remote_filename)
for file in files_to_transfer:
method(file, file.get_filename())
par2temp.deltree()
def put(self, local, remote):
self.transfer(self.wrapped_backend._put, local, remote)
def move(self, local, remote):
self.transfer(self.wrapped_backend._move, local, remote)
def get(self, remote_filename, local_path):
"""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 = (
f"par2 v {self.common_options} {os.fsdecode(par2file.get_canonical())} "
f'"{os.fsdecode(local_path_temp.get_canonical())}"'
)
returncode, out, err = self.subprocess_popen(par2verify)
if returncode:
log.Warn(f"File is corrupt. Try to repair {remote_filename}")
c = re.compile(f"{remote_filename.decode()}\\.vol[\\d+]*\\.par2")
par2volumes = [f for f in self.wrapped_backend._list() if c.match(os.fsdecode(f))]
for filename in par2volumes:
file = par2temp.append(filename)
self.wrapped_backend._get(filename, file)
par2repair = (
f"par2 r {self.common_options} {os.fsdecode(par2file.get_canonical())} "
f'"{os.fsdecode(local_path_temp.get_canonical())}"'
)
returncode, out, err = self.subprocess_popen(par2repair)
if returncode:
log.Error(f"Failed to repair {remote_filename}")
else:
log.Warn(f"Repair successful {remote_filename}")
except BackendException:
# par2 file not available
pass
finally:
local_path_temp.rename(local_path)
par2temp.deltree()
def delete(self, filename):
"""delete given filename and its .par2 files"""
self.wrapped_backend._delete(filename)
remote_list = self.unfiltered_list()
c = re.compile(f"{os.fsdecode(filename)}(?:\\.vol[\\d+]*)?\\.par2")
for remote_filename in remote_list:
if c.match(os.fsdecode(remote_filename)):
self.wrapped_backend._delete(os.fsencode(remote_filename))
def delete_list(self, filename_list):
"""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(f"{os.fsdecode(filename)}(?:\\.vol[\\d+]*)?\\.par2")
for remote_filename in remote_list:
if c.match(os.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, "_delete_list"):
return self.wrapped_backend._delete_list(filename_list)
else:
for filename in filename_list:
self.wrapped_backend._delete(filename)
def list(self):
"""
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("(?!.*\\.par2$)")
filtered_list = []
for filename in remote_list:
if c.match(os.fsdecode(filename)):
filtered_list.append(filename)
return filtered_list
def unfiltered_list(self):
return self.wrapped_backend._list()
def retry_cleanup(self):
self.wrapped_backend._retry_cleanup()
def error_code(self, operation, e):
return self.wrapped_backend._error_code(operation, e)
def query(self, filename):
return self.wrapped_backend._query(filename)
def query_list(self, filename_list):
return self.wrapped_backend._query(filename_list)
def close(self):
self.wrapped_backend._close()
backend.register_backend_prefix("par2", Par2Backend)
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