数据库cdn加速

# 示例代码：使用Redis作为缓存，设置缓存过期时间和更新机制
import redis
import time

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

def get_data(key):
    data = r.get(key)
    if data is None:
        data = fetch_from_database(key)  # 从数据库获取数据
        r.setex(key, 3600, data)  # 设置缓存过期时间为1小时
    return data

def update_data(key, new_data):
    r.delete(key)  # 删除旧缓存
    save_to_database(key, new_data)  # 更新数据库
    r.setex(key, 3600, new_data)  # 设置新缓存

# 示例代码：使用布隆过滤器防止缓存穿透
from bloom_filter import BloomFilter

bf = BloomFilter(capacity=1000000, error_rate=0.001)

def get_data(key):
    if not bf.contains(key):
        return None  # 数据不可能存在，直接返回空值
    data = r.get(key)
    if data is None:
        data = fetch_from_database(key)
        r.setex(key, 3600, data)
    return data

# 示例代码：使用分布式锁防止缓存雪崩
import redis
import time

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

def get_data(key):
    data = r.get(key)
    if data is None:
        lock = r.lock(f"lock:{key}", timeout=10)
        if lock.acquire():
            try:
                data = r.get(key)
                if data is None:
                    data = fetch_from_database(key)
                    r.setex(key, 3600 + random.randint(0, 60), data)  # 设置随机过期时间
            finally:
                lock.release()
    return data