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Code Issues Releases Wiki Activity

cache sync/remote: compressed, decrypted cache

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This commit is contained in:
Marian Beermann 2017-05-28 13:16:52 +02:00
parent c786a5941e
commit 835b0e5ee0
2 changed files with 70 additions and 29 deletions
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18
src/borg/cache.py
View file

@ -564,17 +564,15 @@ def cleanup_cached_archive(id):
except FileNotFoundError:
pass
def fetch_and_build_idx(archive_id, repository, key, chunk_idx):
cdata = repository.get(archive_id)
data = key.decrypt(archive_id, cdata)
chunk_idx.add(archive_id, 1, len(data), len(cdata))
def fetch_and_build_idx(archive_id, decrypted_repository, key, chunk_idx):
csize, data = decrypted_repository.get(archive_id)
chunk_idx.add(archive_id, 1, len(data), csize)
archive = ArchiveItem(internal_dict=msgpack.unpackb(data))
if archive.version != 1:
raise Exception('Unknown archive metadata version')
sync = CacheSynchronizer(chunk_idx)
for item_id, chunk in zip(archive.items, repository.get_many(archive.items)):
data = key.decrypt(item_id, chunk)
chunk_idx.add(item_id, 1, len(data), len(chunk))
for item_id, (csize, data) in zip(archive.items, decrypted_repository.get_many(archive.items)):
chunk_idx.add(item_id, 1, len(data), csize)
sync.feed(data)
if self.do_cache:
fn = mkpath(archive_id)
@ -641,7 +639,7 @@ def create_master_idx(chunk_idx):
# above can remove *archive_id* from *cached_ids*.
logger.info('Fetching and building archive index for %s ...', archive_name)
archive_chunk_idx = ChunkIndex()
fetch_and_build_idx(archive_id, repository, self.key, archive_chunk_idx)
fetch_and_build_idx(archive_id, decrypted_repository, self.key, archive_chunk_idx)
logger.info("Merging into master chunks index ...")
if chunk_idx is None:
# we just use the first archive's idx as starting point,
@ -653,7 +651,7 @@ def create_master_idx(chunk_idx):
else:
chunk_idx = chunk_idx or ChunkIndex(master_index_capacity)
logger.info('Fetching archive index for %s ...', archive_name)
fetch_and_build_idx(archive_id, repository, self.key, chunk_idx)
fetch_and_build_idx(archive_id, decrypted_repository, self.key, chunk_idx)
if self.progress:
pi.finish()
logger.info('Done.')
@ -675,7 +673,7 @@ def legacy_cleanup():
pass
self.begin_txn()
with cache_if_remote(self.repository) as repository:
with cache_if_remote(self.repository, decrypted_cache=self.key) as decrypted_repository:
legacy_cleanup()
# TEMPORARY HACK: to avoid archive index caching, create a FILE named ~/.cache/borg/REPOID/chunks.archive.d -
# this is only recommended if you have a fast, low latency connection to your repo (e.g. if repo is local disk)

81
src/borg/remote.py
View file

@ -8,6 +8,7 @@
import select
import shlex
import shutil
import struct
import sys
import tempfile
import textwrap
@ -18,6 +19,7 @@
import msgpack
from . import __version__
from .compress import LZ4
from .helpers import Error, IntegrityError
from .helpers import bin_to_hex
from .helpers import get_home_dir
@ -1046,9 +1048,14 @@ class RepositoryNoCache:
"""A not caching Repository wrapper, passes through to repository.
Just to have same API (including the context manager) as RepositoryCache.
*transform* is a callable taking two arguments, key and raw repository data.
The return value is returned from get()/get_many(). By default, the raw
repository data is returned.
"""
def __init__(self, repository):
def __init__(self, repository, transform=None):
self.repository = repository
self.transform = transform or (lambda key, data: data)
def close(self):
pass
@ -1063,8 +1070,8 @@ def get(self, key):
return next(self.get_many([key], cache=False))
def get_many(self, keys, cache=True):
for data in self.repository.get_many(keys):
yield data
for key, data in zip(keys, self.repository.get_many(keys)):
yield self.transform(key, data)
class RepositoryCache(RepositoryNoCache):
@ -1072,10 +1079,17 @@ class RepositoryCache(RepositoryNoCache):
A caching Repository wrapper.
Caches Repository GET operations locally.
*pack* and *unpack* complement *transform* of the base class.
*pack* receives the output of *transform* and should return bytes,
which are stored in the cache. *unpack* receives these bytes and
should return the initial data (as returned by *transform*).
"""
def __init__(self, repository):
super().__init__(repository)
def __init__(self, repository, pack=None, unpack=None, transform=None):
super().__init__(repository, transform)
self.pack = pack or (lambda data: data)
self.unpack = unpack or (lambda data: data)
self.cache = set()
self.basedir = tempfile.mkdtemp(prefix='borg-cache-')
self.query_size_limit()
@ -1106,11 +1120,15 @@ def backoff(self):
os.unlink(file)
self.evictions += 1
def add_entry(self, key, data):
def add_entry(self, key, data, cache):
transformed = self.transform(key, data)
if not cache:
return transformed
packed = self.pack(transformed)
file = self.key_filename(key)
try:
with open(file, 'wb') as fd:
fd.write(data)
fd.write(packed)
except OSError as os_error:
if os_error.errno == errno.ENOSPC:
self.enospc += 1
@ -1118,11 +1136,11 @@ def add_entry(self, key, data):
else:
raise
else:
self.size += len(data)
self.size += len(packed)
self.cache.add(key)
if self.size > self.size_limit:
self.backoff()
return data
return transformed
def close(self):
logger.debug('RepositoryCache: current items %d, size %s / %s, %d hits, %d misses, %d slow misses (+%.1fs), '
@ -1141,31 +1159,56 @@ def get_many(self, keys, cache=True):
file = self.key_filename(key)
with open(file, 'rb') as fd:
self.hits += 1
yield fd.read()
yield self.unpack(fd.read())
else:
for key_, data in repository_iterator:
if key_ == key:
if cache:
self.add_entry(key, data)
transformed = self.add_entry(key, data, cache)
self.misses += 1
yield data
yield transformed
break
else:
# slow path: eviction during this get_many removed this key from the cache
t0 = time.perf_counter()
data = self.repository.get(key)
self.slow_lat += time.perf_counter() - t0
if cache:
self.add_entry(key, data)
transformed = self.add_entry(key, data, cache)
self.slow_misses += 1
yield data
yield transformed
# Consume any pending requests
for _ in repository_iterator:
pass
def cache_if_remote(repository):
def cache_if_remote(repository, *, decrypted_cache=False, pack=None, unpack=None, transform=None):
"""
Return a Repository(No)Cache for *repository*.
If *decrypted_cache* is a key object, then get and get_many will return a tuple
(csize, plaintext) instead of the actual data in the repository. The cache will
store decrypted data, which increases CPU efficiency (by avoiding repeatedly decrypting
and more importantly MAC and ID checking cached objects).
Internally, objects are compressed with LZ4.
"""
if decrypted_cache and (pack or unpack or transform):
raise ValueError('decrypted_cache and pack/unpack/transform are incompatible')
elif decrypted_cache:
key = decrypted_cache
cache_struct = struct.Struct('=I')
compressor = LZ4()
def pack(data):
return cache_struct.pack(data[0]) + compressor.compress(data[1])
def unpack(data):
return cache_struct.unpack(data[:cache_struct.size])[0], compressor.decompress(data[cache_struct.size:])
def transform(id_, data):
csize = len(data)
decrypted = key.decrypt(id_, data)
return csize, decrypted
if isinstance(repository, RemoteRepository):
return RepositoryCache(repository)
return RepositoryCache(repository, pack, unpack, transform)
else:
return RepositoryNoCache(repository)
return RepositoryNoCache(repository, transform)