mirror of
https://github.com/borgbackup/borg.git
synced 2024-12-26 09:47:58 +00:00
436 lines
16 KiB
Python
436 lines
16 KiB
Python
from configparser import RawConfigParser
|
|
from binascii import hexlify
|
|
import errno
|
|
import os
|
|
import re
|
|
import shutil
|
|
import struct
|
|
from zlib import crc32
|
|
|
|
from .hashindex import NSIndex
|
|
from .helpers import Error, IntegrityError, read_msgpack, write_msgpack, unhexlify, UpgradableLock
|
|
from .lrucache import LRUCache
|
|
|
|
MAX_OBJECT_SIZE = 20 * 1024 * 1024
|
|
MAGIC = b'ATTICSEG'
|
|
TAG_PUT = 0
|
|
TAG_DELETE = 1
|
|
TAG_COMMIT = 2
|
|
|
|
|
|
class Repository(object):
|
|
"""Filesystem based transactional key value store
|
|
|
|
On disk layout:
|
|
dir/README
|
|
dir/config
|
|
dir/data/<X / SEGMENTS_PER_DIR>/<X>
|
|
dir/index.X
|
|
dir/hints.X
|
|
"""
|
|
DEFAULT_MAX_SEGMENT_SIZE = 5 * 1024 * 1024
|
|
DEFAULT_SEGMENTS_PER_DIR = 10000
|
|
|
|
class DoesNotExist(Error):
|
|
"""Repository {} does not exist"""
|
|
|
|
class AlreadyExists(Error):
|
|
"""Repository {} already exists"""
|
|
|
|
class InvalidRepository(Error):
|
|
"""{} is not a valid repository"""
|
|
|
|
|
|
def __init__(self, path, create=False):
|
|
self.path = path
|
|
self.io = None
|
|
self.lock = None
|
|
if create:
|
|
self.create(path)
|
|
self.open(path)
|
|
|
|
def __del__(self):
|
|
self.close()
|
|
|
|
def create(self, path):
|
|
"""Create a new empty repository at `path`
|
|
"""
|
|
if os.path.exists(path) and (not os.path.isdir(path) or os.listdir(path)):
|
|
raise self.AlreadyExists(path)
|
|
if not os.path.exists(path):
|
|
os.mkdir(path)
|
|
with open(os.path.join(path, 'README'), 'w') as fd:
|
|
fd.write('This is an Attic repository\n')
|
|
os.mkdir(os.path.join(path, 'data'))
|
|
config = RawConfigParser()
|
|
config.add_section('repository')
|
|
config.set('repository', 'version', '1')
|
|
config.set('repository', 'segments_per_dir', self.DEFAULT_SEGMENTS_PER_DIR)
|
|
config.set('repository', 'max_segment_size', self.DEFAULT_MAX_SEGMENT_SIZE)
|
|
config.set('repository', 'id', hexlify(os.urandom(32)).decode('ascii'))
|
|
with open(os.path.join(path, 'config'), 'w') as fd:
|
|
config.write(fd)
|
|
|
|
def open(self, path):
|
|
self.head = None
|
|
self.path = path
|
|
if not os.path.isdir(path):
|
|
raise self.DoesNotExist(path)
|
|
self.config = RawConfigParser()
|
|
self.config.read(os.path.join(self.path, 'config'))
|
|
if not 'repository' in self.config.sections() or self.config.getint('repository', 'version') != 1:
|
|
raise self.InvalidRepository(path)
|
|
self.lock = UpgradableLock(os.path.join(path, 'config'))
|
|
self.max_segment_size = self.config.getint('repository', 'max_segment_size')
|
|
self.segments_per_dir = self.config.getint('repository', 'segments_per_dir')
|
|
self.id = unhexlify(self.config.get('repository', 'id').strip())
|
|
self.rollback()
|
|
|
|
def close(self):
|
|
if self.lock:
|
|
self.rollback()
|
|
self.lock.release()
|
|
self.lock = None
|
|
|
|
def commit(self, rollback=True):
|
|
"""Commit transaction
|
|
"""
|
|
self.io.write_commit()
|
|
self.compact_segments()
|
|
self.write_index()
|
|
self.rollback()
|
|
|
|
def _available_indices(self, reverse=False):
|
|
names = [int(name[6:]) for name in os.listdir(self.path) if re.match('index\.\d+', name)]
|
|
names.sort(reverse=reverse)
|
|
return names
|
|
|
|
def open_index(self, head, read_only=False):
|
|
if head is None:
|
|
self.index = NSIndex.create(os.path.join(self.path, 'index.tmp').encode('utf-8'))
|
|
self.segments = {}
|
|
self.compact = set()
|
|
else:
|
|
if read_only:
|
|
self.index = NSIndex((os.path.join(self.path, 'index.%d') % head).encode('utf-8'), readonly=True)
|
|
else:
|
|
shutil.copy(os.path.join(self.path, 'index.%d' % head),
|
|
os.path.join(self.path, 'index.tmp'))
|
|
self.index = NSIndex(os.path.join(self.path, 'index.tmp').encode('utf-8'))
|
|
hints = read_msgpack(os.path.join(self.path, 'hints.%d' % head))
|
|
if hints[b'version'] != 1:
|
|
raise ValueError('Unknown hints file version: %d' % hints['version'])
|
|
self.segments = hints[b'segments']
|
|
self.compact = set(hints[b'compact'])
|
|
|
|
def write_index(self):
|
|
hints = {b'version': 1,
|
|
b'segments': self.segments,
|
|
b'compact': list(self.compact)}
|
|
write_msgpack(os.path.join(self.path, 'hints.%d' % self.io.head), hints)
|
|
self.index.flush()
|
|
os.rename(os.path.join(self.path, 'index.tmp'),
|
|
os.path.join(self.path, 'index.%d' % self.io.head))
|
|
# Remove old indices
|
|
current = '.%d' % self.io.head
|
|
for name in os.listdir(self.path):
|
|
if not name.startswith('index.') and not name.startswith('hints.'):
|
|
continue
|
|
if name.endswith(current):
|
|
continue
|
|
os.unlink(os.path.join(self.path, name))
|
|
|
|
def compact_segments(self):
|
|
"""Compact sparse segments by copying data into new segments
|
|
"""
|
|
if not self.compact:
|
|
return
|
|
|
|
def lookup(tag, key):
|
|
return tag == TAG_PUT and self.index.get(key, (-1, -1))[0] == segment
|
|
segments = self.segments
|
|
for segment in sorted(self.compact):
|
|
if segments[segment] > 0:
|
|
for tag, key, data in self.io.iter_objects(segment, lookup, include_data=True):
|
|
new_segment, offset = self.io.write_put(key, data)
|
|
self.index[key] = new_segment, offset
|
|
segments.setdefault(new_segment, 0)
|
|
segments[new_segment] += 1
|
|
segments[segment] -= 1
|
|
assert segments[segment] == 0
|
|
self.io.write_commit()
|
|
for segment in self.compact:
|
|
assert self.segments.pop(segment) == 0
|
|
self.io.delete_segment(segment)
|
|
self.compact = set()
|
|
|
|
def recover(self, path):
|
|
"""Recover missing index by replaying logs"""
|
|
start = None
|
|
available = self._available_indices()
|
|
if available:
|
|
start = available[-1]
|
|
self.open_index(start)
|
|
for segment, filename in self.io._segment_names():
|
|
if start is not None and segment <= start:
|
|
continue
|
|
self.segments[segment] = 0
|
|
for tag, key, offset in self.io.iter_objects(segment):
|
|
if tag == TAG_PUT:
|
|
try:
|
|
s, _ = self.index[key]
|
|
self.compact.add(s)
|
|
self.segments[s] -= 1
|
|
except KeyError:
|
|
pass
|
|
self.index[key] = segment, offset
|
|
self.segments[segment] += 1
|
|
elif tag == TAG_DELETE:
|
|
try:
|
|
s, _ = self.index.pop(key)
|
|
self.segments[s] -= 1
|
|
self.compact.add(s)
|
|
self.compact.add(segment)
|
|
except KeyError:
|
|
pass
|
|
if self.segments[segment] == 0:
|
|
self.compact.add(segment)
|
|
if self.io.head is not None:
|
|
self.write_index()
|
|
|
|
def rollback(self):
|
|
"""
|
|
"""
|
|
self._active_txn = False
|
|
if self.io:
|
|
self.io.close()
|
|
self.io = LoggedIO(self.path, self.max_segment_size, self.segments_per_dir)
|
|
if self.io.head is not None and not os.path.exists(os.path.join(self.path, 'index.%d' % self.io.head)):
|
|
self.lock.upgrade()
|
|
self.recover(self.path)
|
|
self.open_index(self.io.head, read_only=True)
|
|
|
|
def _len(self):
|
|
return len(self.index)
|
|
|
|
def get(self, id):
|
|
try:
|
|
segment, offset = self.index[id]
|
|
return self.io.read(segment, offset, id)
|
|
except KeyError:
|
|
raise self.DoesNotExist(self.path)
|
|
|
|
def get_many(self, ids, is_preloaded=False):
|
|
for id_ in ids:
|
|
yield self.get(id_)
|
|
|
|
def put(self, id, data, wait=True):
|
|
if not self._active_txn:
|
|
self._active_txn = True
|
|
self.lock.upgrade()
|
|
self.open_index(self.io.head)
|
|
try:
|
|
segment, _ = self.index[id]
|
|
self.segments[segment] -= 1
|
|
self.compact.add(segment)
|
|
segment = self.io.write_delete(id)
|
|
self.segments.setdefault(segment, 0)
|
|
self.compact.add(segment)
|
|
except KeyError:
|
|
pass
|
|
segment, offset = self.io.write_put(id, data)
|
|
self.segments.setdefault(segment, 0)
|
|
self.segments[segment] += 1
|
|
self.index[id] = segment, offset
|
|
|
|
def delete(self, id, wait=True):
|
|
if not self._active_txn:
|
|
self._active_txn = True
|
|
self.lock.upgrade()
|
|
self.open_index(self.io.head)
|
|
try:
|
|
segment, offset = self.index.pop(id)
|
|
self.segments[segment] -= 1
|
|
self.compact.add(segment)
|
|
segment = self.io.write_delete(id)
|
|
self.compact.add(segment)
|
|
self.segments.setdefault(segment, 0)
|
|
except KeyError:
|
|
raise self.DoesNotExist(self.path)
|
|
|
|
def add_callback(self, cb, data):
|
|
cb(None, None, data)
|
|
|
|
def preload(self, ids):
|
|
"""Preload objects (only applies to remote repositories
|
|
"""
|
|
|
|
|
|
class LoggedIO(object):
|
|
|
|
header_fmt = struct.Struct('<IIB')
|
|
assert header_fmt.size == 9
|
|
put_header_fmt = struct.Struct('<IIB32s')
|
|
assert put_header_fmt.size == 41
|
|
header_no_crc_fmt = struct.Struct('<IB')
|
|
assert header_no_crc_fmt.size == 5
|
|
crc_fmt = struct.Struct('<I')
|
|
assert crc_fmt.size == 4
|
|
|
|
_commit = header_no_crc_fmt.pack(9, TAG_COMMIT)
|
|
COMMIT = crc_fmt.pack(crc32(_commit)) + _commit
|
|
|
|
def __init__(self, path, limit, segments_per_dir, capacity=100):
|
|
self.path = path
|
|
self.fds = LRUCache(capacity)
|
|
self.segment = None
|
|
self.limit = limit
|
|
self.segments_per_dir = segments_per_dir
|
|
self.offset = 0
|
|
self._write_fd = None
|
|
self.head = None
|
|
self.cleanup()
|
|
|
|
def close(self):
|
|
for segment in list(self.fds.keys()):
|
|
self.fds.pop(segment).close()
|
|
self.close_segment()
|
|
self.fds = None # Just to make sure we're disabled
|
|
|
|
def _segment_names(self, reverse=False):
|
|
for dirpath, dirs, filenames in os.walk(os.path.join(self.path, 'data')):
|
|
dirs.sort(key=int, reverse=reverse)
|
|
filenames = sorted((filename for filename in filenames if filename.isdigit()), key=int, reverse=reverse)
|
|
for filename in filenames:
|
|
yield int(filename), os.path.join(dirpath, filename)
|
|
|
|
def cleanup(self):
|
|
"""Delete segment files left by aborted transactions
|
|
"""
|
|
self.head = None
|
|
self.segment = 0
|
|
for segment, filename in self._segment_names(reverse=True):
|
|
if self.is_complete_segment(filename):
|
|
self.head = segment
|
|
self.segment = self.head + 1
|
|
return
|
|
else:
|
|
os.unlink(filename)
|
|
|
|
def is_complete_segment(self, filename):
|
|
with open(filename, 'rb') as fd:
|
|
try:
|
|
fd.seek(-self.header_fmt.size, os.SEEK_END)
|
|
except Exception as e:
|
|
# return False if segment file is empty or too small
|
|
if e.errno == errno.EINVAL:
|
|
return False
|
|
raise e
|
|
return fd.read(self.header_fmt.size) == self.COMMIT
|
|
|
|
def segment_filename(self, segment):
|
|
return os.path.join(self.path, 'data', str(segment // self.segments_per_dir), str(segment))
|
|
|
|
def get_write_fd(self, no_new=False):
|
|
if not no_new and self.offset and self.offset > self.limit:
|
|
self.close_segment()
|
|
if not self._write_fd:
|
|
if self.segment % self.segments_per_dir == 0:
|
|
dirname = os.path.join(self.path, 'data', str(self.segment // self.segments_per_dir))
|
|
if not os.path.exists(dirname):
|
|
os.mkdir(dirname)
|
|
self._write_fd = open(self.segment_filename(self.segment), 'ab')
|
|
self._write_fd.write(MAGIC)
|
|
self.offset = 8
|
|
return self._write_fd
|
|
|
|
def get_fd(self, segment):
|
|
try:
|
|
return self.fds[segment]
|
|
except KeyError:
|
|
fd = open(self.segment_filename(segment), 'rb')
|
|
self.fds[segment] = fd
|
|
return fd
|
|
|
|
def delete_segment(self, segment):
|
|
try:
|
|
os.unlink(self.segment_filename(segment))
|
|
except OSError:
|
|
pass
|
|
|
|
def iter_objects(self, segment, lookup=None, include_data=False):
|
|
fd = self.get_fd(segment)
|
|
fd.seek(0)
|
|
if fd.read(8) != MAGIC:
|
|
raise IntegrityError('Invalid segment header')
|
|
offset = 8
|
|
header = fd.read(self.header_fmt.size)
|
|
while header:
|
|
crc, size, tag = self.header_fmt.unpack(header)
|
|
if size > MAX_OBJECT_SIZE:
|
|
raise IntegrityError('Invalid segment object size')
|
|
rest = fd.read(size - self.header_fmt.size)
|
|
if crc32(rest, crc32(memoryview(header)[4:])) & 0xffffffff != crc:
|
|
raise IntegrityError('Segment checksum mismatch')
|
|
if tag not in (TAG_PUT, TAG_DELETE, TAG_COMMIT):
|
|
raise IntegrityError('Invalid segment entry header')
|
|
key = None
|
|
if tag in (TAG_PUT, TAG_DELETE):
|
|
key = rest[:32]
|
|
if not lookup or lookup(tag, key):
|
|
if include_data:
|
|
yield tag, key, rest[32:]
|
|
else:
|
|
yield tag, key, offset
|
|
offset += size
|
|
header = fd.read(self.header_fmt.size)
|
|
|
|
def read(self, segment, offset, id):
|
|
if segment == self.segment:
|
|
self._write_fd.flush()
|
|
fd = self.get_fd(segment)
|
|
fd.seek(offset)
|
|
header = fd.read(self.put_header_fmt.size)
|
|
crc, size, tag, key = self.put_header_fmt.unpack(header)
|
|
if size > MAX_OBJECT_SIZE:
|
|
raise IntegrityError('Invalid segment object size')
|
|
data = fd.read(size - self.put_header_fmt.size)
|
|
if crc32(data, crc32(memoryview(header)[4:])) & 0xffffffff != crc:
|
|
raise IntegrityError('Segment checksum mismatch')
|
|
if tag != TAG_PUT or id != key:
|
|
raise IntegrityError('Invalid segment entry header')
|
|
return data
|
|
|
|
def write_put(self, id, data):
|
|
size = len(data) + self.put_header_fmt.size
|
|
fd = self.get_write_fd()
|
|
offset = self.offset
|
|
header = self.header_no_crc_fmt.pack(size, TAG_PUT)
|
|
crc = self.crc_fmt.pack(crc32(data, crc32(id, crc32(header))) & 0xffffffff)
|
|
fd.write(b''.join((crc, header, id, data)))
|
|
self.offset += size
|
|
return self.segment, offset
|
|
|
|
def write_delete(self, id):
|
|
fd = self.get_write_fd()
|
|
header = self.header_no_crc_fmt.pack(self.put_header_fmt.size, TAG_DELETE)
|
|
crc = self.crc_fmt.pack(crc32(id, crc32(header)) & 0xffffffff)
|
|
fd.write(b''.join((crc, header, id)))
|
|
self.offset += self.put_header_fmt.size
|
|
return self.segment
|
|
|
|
def write_commit(self):
|
|
fd = self.get_write_fd(no_new=True)
|
|
header = self.header_no_crc_fmt.pack(self.header_fmt.size, TAG_COMMIT)
|
|
crc = self.crc_fmt.pack(crc32(header) & 0xffffffff)
|
|
fd.write(b''.join((crc, header)))
|
|
self.head = self.segment
|
|
self.close_segment()
|
|
|
|
def close_segment(self):
|
|
if self._write_fd:
|
|
self.segment += 1
|
|
self.offset = 0
|
|
os.fsync(self._write_fd)
|
|
self._write_fd.close()
|
|
self._write_fd = None
|