Merge pull request #1778 from coreos-inc/redlock

Fix locking via RedLock
This commit is contained in:
josephschorr 2016-08-29 16:12:01 -04:00 committed by GitHub
commit 5c64646629
2 changed files with 63 additions and 43 deletions

View file

@ -7,6 +7,11 @@ from app import app
logger = logging.getLogger(__name__)
class LockNotAcquiredException(Exception):
""" Exception raised if a GlobalLock could not be acquired. """
class GlobalLock(object):
""" A lock object that blocks globally via Redis. Note that Redis is not considered a tier-1
service, so this lock should not be used for any critical code paths.
@ -20,17 +25,22 @@ class GlobalLock(object):
self._redlock = None
def __enter__(self):
return self.lock()
if not self.acquire():
raise LockNotAcquiredException()
def __exit__(self ,type, value, traceback):
self.unlock()
def __exit__(self, type, value, traceback):
self.release()
def lock(self):
def acquire(self):
logger.debug('Acquiring global lock %s', self._lock_name)
try:
redlock = RedLock(self._lock_name, connection_details=[self._redis_info],
ttl=self._lock_ttl)
redlock.acquire()
ttl=self._lock_ttl)
acquired = redlock.acquire()
if not acquired:
logger.debug('Was unable to not acquire lock %s', self._lock_name)
return False
self._redlock = redlock
logger.debug('Acquired lock %s', self._lock_name)
return True
@ -41,10 +51,15 @@ class GlobalLock(object):
logger.debug('Could not connect to Redis for lock %s: %s', self._lock_name, re)
return False
def unlock(self):
def release(self):
if self._redlock is not None:
logger.debug('Releasing lock %s', self._lock_name)
self._redlock.release()
try:
self._redlock.release()
except RedLockError:
logger.debug('Could not release lock %s', self._lock_name)
except RedisError as re:
logger.debug('Could not connect to Redis for releasing lock %s: %s', self._lock_name, re)
logger.debug('Released lock %s', self._lock_name)
self._redlock = None

View file

@ -12,7 +12,7 @@ from data.database import UseThenDisconnect
from data.model.log import (get_stale_logs, get_stale_logs_start_id,
get_stale_logs_cutoff_id, delete_stale_logs)
from data.userfiles import DelegateUserfiles
from util.locking import GlobalLock
from util.locking import GlobalLock, LockNotAcquiredException
from util.streamingjsonencoder import StreamingJSONEncoder
from workers.worker import Worker
@ -23,7 +23,7 @@ STALE_AFTER = timedelta(days=30)
MIN_LOGS_PER_ROTATION = 10000
MEMORY_TEMPFILE_SIZE = 12 * 1024 * 1024
WORKER_FREQUENCY = app.config.get('ACTION_LOG_ROTATION_FREQUENCY', 60 * 60 * 24)
WORKER_FREQUENCY = app.config.get('ACTION_LOG_ROTATION_FREQUENCY', 60 * 60 * 12)
SAVE_PATH = app.config.get('ACTION_LOG_ARCHIVE_PATH')
SAVE_LOCATION = app.config.get('ACTION_LOG_ARCHIVE_LOCATION')
@ -36,8 +36,6 @@ class LogRotateWorker(Worker):
def _archive_logs(self):
logger.debug('Attempting to rotate log entries')
log_archive = DelegateUserfiles(app, storage, SAVE_LOCATION, SAVE_PATH)
with UseThenDisconnect(app.config):
cutoff_date = datetime.now() - STALE_AFTER
cutoff_id = get_stale_logs_cutoff_id(cutoff_date)
@ -45,44 +43,51 @@ class LogRotateWorker(Worker):
logger.warning('Failed to find cutoff id')
return
while True:
with GlobalLock('ACTION_LOG_ROTATION') as gl:
if not gl:
logger.debug('Could not acquire global lock; sleeping')
return
logs_archived = True
while logs_archived:
try:
with GlobalLock('ACTION_LOG_ROTATION'):
logs_archived = self._perform_archiving(cutoff_id)
except LockNotAcquiredException:
return
with UseThenDisconnect(app.config):
start_id = get_stale_logs_start_id()
def _perform_archiving(self, cutoff_id):
log_archive = DelegateUserfiles(app, storage, SAVE_LOCATION, SAVE_PATH)
if start_id is None:
logger.warning('Failed to find start id')
return
with UseThenDisconnect(app.config):
start_id = get_stale_logs_start_id()
logger.debug('Found starting ID %s and cutoff ID %s', start_id, cutoff_id)
if start_id is None:
logger.warning('Failed to find start id')
return False
approx_count = cutoff_id - start_id
if approx_count < MIN_LOGS_PER_ROTATION:
logger.debug('Not enough stale logs to warrant rotation (approx %d)', approx_count)
return
logger.debug('Found starting ID %s and cutoff ID %s', start_id, cutoff_id)
end_id = start_id + MIN_LOGS_PER_ROTATION
logs = [log_dict(log) for log in get_stale_logs(start_id, end_id)]
approx_count = cutoff_id - start_id
if approx_count < MIN_LOGS_PER_ROTATION:
logger.debug('Not enough stale logs to warrant rotation (approx %d)', approx_count)
return False
logger.debug('Archiving logs from IDs %s to %s', start_id, end_id)
with SpooledTemporaryFile(MEMORY_TEMPFILE_SIZE) as tempfile:
with GzipFile('temp_action_log_rotate', fileobj=tempfile, compresslevel=1) as zipstream:
for chunk in StreamingJSONEncoder().iterencode(logs):
zipstream.write(chunk)
end_id = start_id + MIN_LOGS_PER_ROTATION
logs = [log_dict(log) for log in get_stale_logs(start_id, end_id)]
tempfile.seek(0)
filename = '%d-%d.txt.gz' % (start_id, end_id)
log_archive.store_file(tempfile, JSON_MIMETYPE, content_encoding='gzip',
file_id=filename)
logger.debug('Finished archiving logs from IDs %s to %s', start_id, end_id)
logger.debug('Archiving logs from IDs %s to %s', start_id, end_id)
with SpooledTemporaryFile(MEMORY_TEMPFILE_SIZE) as tempfile:
with GzipFile('temp_action_log_rotate', fileobj=tempfile, compresslevel=1) as zipstream:
for chunk in StreamingJSONEncoder().iterencode(logs):
zipstream.write(chunk)
with UseThenDisconnect(app.config):
logger.debug('Deleting logs from IDs %s to %s', start_id, end_id)
delete_stale_logs(start_id, end_id)
tempfile.seek(0)
filename = '%d-%d.txt.gz' % (start_id, end_id)
log_archive.store_file(tempfile, JSON_MIMETYPE, content_encoding='gzip',
file_id=filename)
logger.debug('Finished archiving logs from IDs %s to %s', start_id, end_id)
with UseThenDisconnect(app.config):
logger.debug('Deleting logs from IDs %s to %s', start_id, end_id)
delete_stale_logs(start_id, end_id)
return True
def log_dict(log):