安全存储秒杀

import redis
import time

r = redis.Redis(host='localhost', port=6379, db=0)

def seckill(product_id, user_id):
    key = f"stock:{product_id}"
    stock = r.get(key)
    
    if stock is None or int(stock) <= 0:
        return "秒杀失败，商品已售罄"
    
    # 使用WATCH命令监控stock键的变化
    with r.pipeline() as pipe:
        while True:
            try:
                pipe.watch(key)
                current_stock = int(pipe.get(key))
                if current_stock <= 0:
                    return "秒杀失败，商品已售罄"
                
                # 开启事务
                pipe.multi()
                pipe.decr(key)  # 减少库存
                pipe.execute()  # 执行事务
                
                # 记录秒杀成功信息（此处可插入数据库操作）
                print(f"用户{user_id}秒杀商品{product_id}成功")
                return "秒杀成功"
            except redis.WatchError:
                continue  # 若监控的键被其他客户端修改，则重试

# 模拟秒杀场景
for i in range(100):
    threading.Thread(target=seckill, args=(1, i)).start()