borg/darc/archive.py

381 lines
14 KiB
Python

from __future__ import with_statement
from datetime import datetime, timedelta
from getpass import getuser
import msgpack
import os
import socket
import stat
import sys
from cStringIO import StringIO
from xattr import xattr, XATTR_NOFOLLOW
from ._speedups import chunkify
from .helpers import uid2user, user2uid, gid2group, group2gid, \
Counter, encode_filename, Statistics
ITEMS_BUFFER = 1024 * 1024
CHUNK_SIZE = 64 * 1024
WINDOW_SIZE = 4096
have_lchmod = hasattr(os, 'lchmod')
linux = sys.platform == 'linux2'
class Archive(object):
class DoesNotExist(Exception):
pass
def __init__(self, store, key, name=None, cache=None):
self.key = key
self.store = store
self.cache = cache
self.items = StringIO()
self.items_ids = []
self.hard_links = {}
self.stats = Statistics()
if name:
manifest = Archive.read_manifest(self.store, self.key)
try:
info = manifest['archives'][name]
except KeyError:
raise Archive.DoesNotExist
self.load(info['id'])
@staticmethod
def read_manifest(store, key):
mid = store.meta['manifest']
if not mid:
return {'version': 1, 'archives': {}}
mid = mid.decode('hex')
data = key.decrypt(mid, store.get(mid))
manifest = msgpack.unpackb(data)
if not manifest.get('version') == 1:
raise ValueError('Invalid manifest version')
return manifest
def write_manifest(self, manifest):
mid = self.store.meta['manifest']
if mid:
self.cache.chunk_decref(mid.decode('hex'))
if manifest:
data = msgpack.packb(manifest)
mid = self.key.id_hash(data)
self.cache.add_chunk(mid, data, self.stats)
self.store.meta['manifest'] = mid.encode('hex')
else:
self.store.meta['manifest'] = ''
def load(self, id):
self.id = id
data = self.key.decrypt(self.id, self.store.get(self.id))
self.metadata = msgpack.unpackb(data)
if self.metadata['version'] != 1:
raise Exception('Unknown archive metadata version')
self.name = self.metadata['name']
@property
def ts(self):
"""Timestamp of archive creation in UTC"""
t, f = self.metadata['time'].split('.', 1)
return datetime.strptime(t, '%Y-%m-%dT%H:%M:%S') + timedelta(seconds=float('.' + f))
def __repr__(self):
return 'Archive(%r)' % self.name
def iter_items(self, callback):
unpacker = msgpack.Unpacker()
counter = Counter(0)
def cb(chunk, error, id):
if error:
raise error
assert not error
counter.dec()
data = self.key.decrypt(id, chunk)
unpacker.feed(data)
for item in unpacker:
callback(item)
for id in self.metadata['items']:
# Limit the number of concurrent items requests to 10
self.store.flush_rpc(counter, 10)
counter.inc()
self.store.get(id, callback=cb, callback_data=id)
def add_item(self, item):
self.items.write(msgpack.packb(item))
if self.items.tell() > ITEMS_BUFFER:
self.flush_items()
def flush_items(self, flush=False):
if self.items.tell() == 0:
return
self.items.seek(0)
chunks = list(str(s) for s in chunkify(self.items, CHUNK_SIZE, WINDOW_SIZE, self.key.chunk_seed))
self.items.seek(0)
self.items.truncate()
for chunk in chunks[:-1]:
id, _, _ = self.cache.add_chunk(self.key.id_hash(chunk), chunk, self.stats)
self.items_ids.append(id)
if flush or len(chunks) == 1:
id, _, _ = self.cache.add_chunk(self.key.id_hash(chunks[-1]), chunks[-1], self.stats)
self.items_ids.append(id)
else:
self.items.write(chunks[-1])
def save(self, name, cache):
self.flush_items(flush=True)
metadata = {
'version': 1,
'name': name,
'items': self.items_ids,
'cmdline': sys.argv,
'hostname': socket.gethostname(),
'username': getuser(),
'time': datetime.utcnow().isoformat(),
}
data = msgpack.packb(metadata)
self.id = self.key.id_hash(data)
cache.add_chunk(self.id, data, self.stats)
manifest = Archive.read_manifest(self.store, self.key)
assert not name in manifest['archives']
manifest['archives'][name] = {'id': self.id, 'time': metadata['time']}
self.write_manifest(manifest)
self.store.commit()
cache.commit()
def calc_stats(self, cache):
# This function is a bit evil since it abuses the cache to calculate
# the stats. The cache transaction must be rolled back afterwards
def cb(chunk, error, id):
assert not error
data = self.key.decrypt(id, chunk)
unpacker.feed(data)
for item in unpacker:
try:
for id, size, csize in item['chunks']:
count, _, _ = self.cache.chunks[id]
stats.update(size, csize, count==1)
stats.nfiles += 1
self.cache.chunks[id] = count - 1, size, csize
except KeyError:
pass
unpacker = msgpack.Unpacker()
cache.begin_txn()
stats = Statistics()
for id in self.metadata['items']:
self.store.get(id, callback=cb, callback_data=id)
count, size, csize = self.cache.chunks[id]
stats.update(size, csize, count==1)
self.cache.chunks[id] = count - 1, size, csize
self.store.flush_rpc()
cache.rollback()
return stats
def extract_item(self, item, dest=None, start_cb=None, restore_attrs=True):
dest = dest or os.getcwdu()
dir_stat_queue = []
assert item['path'][0] not in ('/', '\\', ':')
path = os.path.join(dest, encode_filename(item['path']))
mode = item['mode']
if stat.S_ISDIR(mode):
if not os.path.exists(path):
os.makedirs(path)
if restore_attrs:
self.restore_attrs(path, item)
elif stat.S_ISFIFO(mode):
if not os.path.exists(os.path.dirname(path)):
os.makedirs(os.path.dirname(path))
os.mkfifo(path)
self.restore_attrs(path, item)
elif stat.S_ISLNK(mode):
if not os.path.exists(os.path.dirname(path)):
os.makedirs(os.path.dirname(path))
source = item['source']
if os.path.exists(path):
os.unlink(path)
os.symlink(source, path)
self.restore_attrs(path, item, symlink=True)
elif stat.S_ISREG(mode):
if not os.path.exists(os.path.dirname(path)):
os.makedirs(os.path.dirname(path))
# Hard link?
if 'source' in item:
source = os.path.join(dest, item['source'])
if os.path.exists(path):
os.unlink(path)
os.link(source, path)
else:
def extract_cb(chunk, error, (id, i)):
if i == 0:
state['fd'] = open(path, 'wb')
start_cb(item)
assert not error
data = self.key.decrypt(id, chunk)
state['fd'].write(data)
if i == n - 1:
state['fd'].close()
self.restore_attrs(path, item)
state = {}
n = len(item['chunks'])
## 0 chunks indicates an empty (0 bytes) file
if n == 0:
open(path, 'wb').close()
start_cb(item)
self.restore_attrs(path, item)
else:
for i, (id, size, csize) in enumerate(item['chunks']):
self.store.get(id, callback=extract_cb, callback_data=(id, i))
else:
raise Exception('Unknown archive item type %r' % item['mode'])
def restore_attrs(self, path, item, symlink=False):
xattrs = item.get('xattrs')
if xattrs:
xa = xattr(path, XATTR_NOFOLLOW)
for k, v in xattrs.items():
try:
xa.set(k, v)
except (IOError, KeyError):
pass
if have_lchmod:
os.lchmod(path, item['mode'])
elif not symlink:
os.chmod(path, item['mode'])
uid = user2uid(item['user']) or item['uid']
gid = group2gid(item['group']) or item['gid']
try:
os.lchown(path, uid, gid)
except OSError:
pass
if not symlink:
# FIXME: We should really call futimes here (c extension required)
os.utime(path, (item['mtime'], item['mtime']))
def verify_file(self, item, start, result):
def verify_chunk(chunk, error, (id, i)):
if error:
if not state:
result(item, False)
state[True] = True
return
if i == 0:
start(item)
data = self.key.decrypt(id, chunk)
if i == n - 1:
result(item, True)
state = {}
n = len(item['chunks'])
if n == 0:
start(item)
result(item, True)
else:
for i, (id, size, csize) in enumerate(item['chunks']):
self.store.get(id, callback=verify_chunk, callback_data=(id, i))
def delete(self, cache):
def callback(chunk, error, id):
assert not error
data = self.key.decrypt(id, chunk)
unpacker.feed(data)
for item in unpacker:
try:
for chunk_id, size, csize in item['chunks']:
self.cache.chunk_decref(chunk_id)
except KeyError:
pass
self.cache.chunk_decref(id)
unpacker = msgpack.Unpacker()
for id in self.metadata['items']:
self.store.get(id, callback=callback, callback_data=id)
self.store.flush_rpc()
self.cache.chunk_decref(self.id)
manifest = Archive.read_manifest(self.store, self.key)
assert self.name in manifest['archives']
del manifest['archives'][self.name]
self.write_manifest(manifest)
self.store.commit()
cache.commit()
def stat_attrs(self, st, path):
item = {
'mode': st.st_mode,
'uid': st.st_uid, 'user': uid2user(st.st_uid),
'gid': st.st_gid, 'group': gid2group(st.st_gid),
'mtime': st.st_mtime,
}
try:
xa = xattr(path, XATTR_NOFOLLOW)
xattrs = {}
for key in xa:
# Only store the user namespace on Linux
if linux and not key.startswith('user'):
continue
xattrs[key] = xa[key]
if xattrs:
item['xattrs'] = xattrs
except IOError:
pass
return item
def process_dir(self, path, st):
item = {'path': path.lstrip('/\\:')}
item.update(self.stat_attrs(st, path))
self.add_item(item)
def process_fifo(self, path, st):
item = {'path': path.lstrip('/\\:')}
item.update(self.stat_attrs(st, path))
self.add_item(item)
def process_symlink(self, path, st):
source = os.readlink(path)
item = {'path': path.lstrip('/\\:'), 'source': source}
item.update(self.stat_attrs(st, path))
self.add_item(item)
def process_file(self, path, st, cache):
safe_path = path.lstrip('/\\:')
# Is it a hard link?
if st.st_nlink > 1:
source = self.hard_links.get((st.st_ino, st.st_dev))
if (st.st_ino, st.st_dev) in self.hard_links:
item = self.stat_attrs(st, path)
item.update({'path': safe_path, 'source': source})
self.add_item(item)
return
else:
self.hard_links[st.st_ino, st.st_dev] = safe_path
path_hash = self.key.id_hash(path)
ids = cache.file_known_and_unchanged(path_hash, st)
chunks = None
if ids is not None:
# Make sure all ids are available
for id in ids:
if not cache.seen_chunk(id):
break
else:
chunks = [cache.chunk_incref(id, self.stats) for id in ids]
# Only chunkify the file if needed
if chunks is None:
with open(path, 'rb') as fd:
chunks = []
for chunk in chunkify(fd, CHUNK_SIZE, WINDOW_SIZE,
self.key.chunk_seed):
chunks.append(cache.add_chunk(self.key.id_hash(chunk), chunk, self.stats))
ids = [id for id, _, _ in chunks]
cache.memorize_file(path_hash, st, ids)
item = {'path': safe_path, 'chunks': chunks}
item.update(self.stat_attrs(st, path))
self.stats.nfiles += 1
self.add_item(item)
@staticmethod
def list_archives(store, key, cache=None):
manifest = Archive.read_manifest(store, key)
for name, info in manifest['archives'].items():
archive = Archive(store, key, cache=cache)
archive.load(info['id'])
yield archive