Redis实现锁续期的项目实践

local lockKey = KEYS[1]
local clientId = ARGV[1]
local newTimeout = tonumber(ARGV[2])

-- Check if the lock is held by the client
if redis.call("get", lockKey) == clientId then
    -- Extend the lock timeout
    redis.call("expire", lockKey, newTimeout)
end

import redis
import time
from threading import Thread

def acquire_lock(redis_client, lock_key, client_id, timeout):
    return redis_client.set(lock_key, client_id, nx=True, ex=timeout)

def extend_lock(redis_client, lock_key, client_id, new_timeout):
    lua_script = """
    local lockKey = KEYS[1]
    local clientId = ARGV[1]
    local newTimeout = tonumber(ARGV[2])

    if redis.call("get", lockKey) == clientId then
        redis.call("expire", lockKey, newTimeout)
    end
    """
    # 使用 EVAL 执行 Lua 脚本
    return redis_client.eval(lua_script, 1, lock_key, client_id, new_timeout)

def renew_lock(redis_client, lock_key, client_id, initial_timeout, renew_interval):
    while True:
        # 尝试续期锁
        extend_lock(redis_client, lock_key, client_id, initial_timeout)
        time.sleep(renew_interval)

def main():
    redis_client = redis.Redis(host='localhost', port=6379, db=0)
    lock_key = "lock:example"
    client_id = "client1"
    initial_timeout = 60  # 初始锁超时时间
    renew_interval = 15   # 续期间隔

    # 获取锁
    if acquire_lock(redis_client, lock_key, client_id, initial_timeout):
        print(f"Client {client_id} acquired the lock.")
        
        # 启动续期线程
        renew_thread = Thread(target=renew_lock, args=(redis_client, lock_key, client_id, initial_timeout, renew_interval))
        renew_thread.start()

        # 执行长时间运行的任务
        try:
            do_long_running_task()
        finally:
            # 在任务完成后释放锁
            release_lock(redis_client, lock_key, client_id)
            renew_thread.join()  # 等待续期线程结束
    else:
        print(f"Client {client_id} failed to acquire the lock.")

def release_lock(redis_client, lock_key, client_id):
    if redis_client.get(lock_key) == client_id:
        redis_client.delete(lock_key)

def do_long_running_task():
    # 模拟长时间运行的任务
    time.sleep(120)
    print("Long running task completed.")

if __name__ == '__main__':
    main()