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backends.py
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# -*- coding: utf-8 -*-
# Copyright (C) 2015-2018 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# This program 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 Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/
import time
import errno
import logging
import gevent
from dogpile.cache.backends import memory as memory_backend
from dogpile.cache.backends import file as file_backend
from dogpile.cache.backends import redis as redis_backend
from dogpile.cache.backends.file import NO_VALUE, compat, FileLock
from dogpile.cache.util import memoized_property
from lru import LRU as LRUDict
_default_max_size = 1024
log = logging.getLogger(__name__)
class LRUMemoryBackend(memory_backend.MemoryBackend):
pickle_values = False
def __init__(self, arguments):
max_size = arguments.pop('max_size', _default_max_size)
callback = None
if arguments.pop('log_max_size_reached', None):
def evicted(key, value):
log.debug(
'LRU: evicting key `%s` due to max size %s reach', key, max_size)
callback = evicted
arguments['cache_dict'] = LRUDict(max_size, callback=callback)
super(LRUMemoryBackend, self).__init__(arguments)
def delete(self, key):
if self._cache.has_key(key):
del self._cache[key]
def delete_multi(self, keys):
for key in keys:
if self._cache.has_key(key):
del self._cache[key]
class Serializer(object):
def _dumps(self, value, safe=False):
try:
return compat.pickle.dumps(value)
except Exception:
if safe:
return NO_VALUE
else:
raise
def _loads(self, value, safe=True):
try:
return compat.pickle.loads(value)
except Exception:
if safe:
return NO_VALUE
else:
raise
class CustomLockFactory(FileLock):
@memoized_property
def _module(self):
import fcntl
flock_org = fcntl.flock
def gevent_flock(fd, operation):
"""
Gevent compatible flock
"""
# set non-blocking, this will cause an exception if we cannot acquire a lock
operation |= fcntl.LOCK_NB
start_lock_time = time.time()
timeout = 60 * 5 # 5min
while True:
try:
flock_org(fd, operation)
# lock has been acquired
break
except (OSError, IOError) as e:
# raise on other errors than Resource temporarily unavailable
if e.errno != errno.EAGAIN:
raise
elif (time.time() - start_lock_time) > timeout:
# waited to much time on a lock, better fail than loop for ever
raise
log.debug('Failed to acquire lock, retry in 0.1')
gevent.sleep(0.1)
fcntl.flock = gevent_flock
return fcntl
class FileNamespaceBackend(Serializer, file_backend.DBMBackend):
def __init__(self, arguments):
arguments['lock_factory'] = CustomLockFactory
super(FileNamespaceBackend, self).__init__(arguments)
def list_keys(self, prefix=''):
def cond(v):
if not prefix:
return True
if v.startswith(prefix):
return True
return False
with self._dbm_file(True) as dbm:
return filter(cond, dbm.keys())
def get_store(self):
return self.filename
def get(self, key):
with self._dbm_file(False) as dbm:
if hasattr(dbm, 'get'):
value = dbm.get(key, NO_VALUE)
else:
# gdbm objects lack a .get method
try:
value = dbm[key]
except KeyError:
value = NO_VALUE
if value is not NO_VALUE:
value = self._loads(value)
return value
def set(self, key, value):
with self._dbm_file(True) as dbm:
dbm[key] = self._dumps(value)
def set_multi(self, mapping):
with self._dbm_file(True) as dbm:
for key, value in mapping.items():
dbm[key] = self._dumps(value)
class RedisPickleBackend(Serializer, redis_backend.RedisBackend):
def list_keys(self, prefix=''):
if prefix:
prefix = prefix + '*'
return self.client.keys(prefix)
def get_store(self):
return self.client.connection_pool
def get(self, key):
value = self.client.get(key)
if value is None:
return NO_VALUE
return self._loads(value)
def set(self, key, value):
if self.redis_expiration_time:
self.client.setex(key, self.redis_expiration_time,
self._dumps(value))
else:
self.client.set(key, self._dumps(value))
def set_multi(self, mapping):
mapping = dict(
(k, self._dumps(v))
for k, v in mapping.items()
)
if not self.redis_expiration_time:
self.client.mset(mapping)
else:
pipe = self.client.pipeline()
for key, value in mapping.items():
pipe.setex(key, self.redis_expiration_time, value)
pipe.execute()