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Copy path177.py
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57 lines (48 loc) · 1.82 KB
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from contextlib import contextmanager
from threading import Lock
from typing import TYPE_CHECKING, Any
from expiringdict import ExpiringDict
if TYPE_CHECKING:
from redis import Redis
from redis.lock import Lock as RedisLock
class RedisKeyedMutex:
"""
This class provides a mutex that can be locked and unlocked by a specific key,
using Redis as a distributed locking provider.
It uses an ExpiringDict to automatically clear the mutex after a specified timeout,
in case the key is not unlocked for a specified duration, to prevent memory leaks.
"""
def __init__(self, redis: "Redis", timeout: int | None = 60):
self.redis = redis
self.timeout = timeout
self.locks: dict[Any, "RedisLock"] = ExpiringDict(
max_len=6000, max_age_seconds=self.timeout
)
self.locks_lock = Lock()
@contextmanager
def locked(self, key: Any):
lock = self.acquire(key)
try:
yield
finally:
if lock.locked():
lock.release()
def acquire(self, key: Any) -> "RedisLock":
"""Acquires and returns a lock with the given key"""
with self.locks_lock:
if key not in self.locks:
self.locks[key] = self.redis.lock(
str(key), self.timeout, thread_local=False
)
lock = self.locks[key]
lock.acquire()
return lock
def release(self, key: Any):
if (lock := self.locks.get(key)) and lock.locked() and lock.owned():
lock.release()
def release_all_locks(self):
"""Call this on process termination to ensure all locks are released"""
self.locks_lock.acquire(blocking=False)
for lock in self.locks.values():
if lock.locked() and lock.owned():
lock.release()