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Files
quay/util/locking.py
Marcus Kok 780bca5eeb locking: change log severity (PROJQUAY-5221) (#1820)
When worker fails to acquire lock make sure a log message is sent as a warning for better visibility when troubleshooting.
2023-04-10 09:56:48 -04:00

97 lines
2.7 KiB
Python

import functools
import logging
from redis import Redis, RedisError
import redis_lock
logger = logging.getLogger(__name__)
class LockNotAcquiredException(Exception):
"""
Exception raised if a GlobalLock could not be acquired.
"""
def _redis_lock_factory(config):
_redis_info = dict(config["USER_EVENTS_REDIS"])
_redis_info.update(
{
"socket_connect_timeout": 5,
"socket_timeout": 5,
"single_connection_client": True,
}
)
_conn = Redis(**_redis_info)
return functools.partial(redis_lock.Lock, _conn)
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.
"""
lock_factory = None
@classmethod
def configure(cls, config):
if cls.lock_factory is None:
cls.lock_factory = _redis_lock_factory(config)
def __init__(self, name, lock_ttl=600, auto_renewal=False):
if GlobalLock.lock_factory is None:
raise LockNotAcquiredException("GlobalLock not configured")
self._lock_name = name
self._lock_ttl = lock_ttl
self._auto_renewal = auto_renewal
self._lock = None
def __enter__(self):
if not self.acquire():
raise LockNotAcquiredException()
def __exit__(self, type, value, traceback):
self.release()
def acquire(self):
logger.debug("Acquiring global lock %s", self._lock_name)
try:
self._lock = GlobalLock.lock_factory(
self._lock_name, expire=self._lock_ttl, auto_renewal=self._auto_renewal
)
acquired = self._lock.acquire()
if not acquired:
logger.debug("Was unable to not acquire lock %s", self._lock_name)
return False
logger.debug("Acquired lock %s", self._lock_name)
return True
except RedisError as re:
logger.warning("Could not connect to Redis for lock %s: %s", self._lock_name, re)
return False
except:
logger.debug("Could not acquire lock %s", self._lock_name)
return False
def release(self):
if self._lock is not None:
logger.debug("Releasing lock %s", self._lock_name)
try:
self._lock.release()
except RedisError as re:
logger.debug(
"Could not connect to Redis for releasing lock %s: %s", self._lock_name, re
)
except:
logger.debug("Could not release lock %s", self._lock_name)
logger.debug("Released lock %s", self._lock_name)
self._lock = None