python-redis-lock是如何实现锁自动续期的

在Python中实现Redis锁的自动续期，通常需要在获取锁之后，开启一个后台线程或者使用定时器，周期性地刷新锁的有效期。

以下是一个简单的例子，使用threading.Timer实现自动续期的Redis锁：

import redis
import threading
import time
 
class RedisLock:
    def __init__(self, redis_conn, lock_name, expire_time=10):
        self.redis_conn = redis_conn
        self.lock_name = lock_name
        self.expire_time = expire_time
        self.timer = None
 
    def acquire(self):
        identifier = str(uuid.uuid4())
        end = time.time() + self.expire_time
        while time.time() < end:
            if self.redis_conn.set(self.lock_name, identifier, ex=self.expire_time, nx=True):
                self.renew_lock(identifier)
                return True
            time.sleep(0.001)
        return False
 
    def release(self, identifier):
        pipe = self.redis_conn.pipeline(True)
        while True:
            try:
                pipe.watch(self.lock_name)
                if pipe.get(self.lock_name) == identifier:
                    pipe.multi()
                    pipe.delete(self.lock_name)
                    pipe.execute()
                    self.stop_renewal()
                    return True
                pipe.unwatch()
                break
            except redis.exceptions.WatchError:
                pass
        return False
 
    def renew_lock(self, identifier):
        def renew():
            while True:
                self.redis_conn.expire(self.lock_name, self.expire_time)
                time.sleep(self.expire_time * 0.75)
 
        self.timer = threading.Timer(self.expire_time * 0.75, renew)
        self.timer.daemon = True
        self.timer.start()
 
    def stop_renewal(self):
        if self.timer:
            self.timer.cancel()
            self.timer = None
 
# 使用方法
redis_conn = redis.Redis()
lock = RedisLock(redis_conn, 'my_lock', expire_time=10)
if lock.acquire(