如何实现PHP后端功能开发中的分布式缓存管理？

<?php

class CacheManager
{
    private $servers = []; // 缓存服务器列表
    private $hashRing = []; // 一致性哈希环
    
    public function __construct($servers)
    {
        $this->servers = $servers;
        $this->buildHashRing();
    }
    
    // 初始化一致性哈希环
    private function buildHashRing()
    {
        foreach ($this->servers as $server) {
            for ($i = 0; $i < 5; $i++) { // 每个服务器虚拟5个节点
                $hash = crc32($server . '-' . $i);
                $this->hashRing[$hash] = $server;
            }
        }
        ksort($this->hashRing); // 按哈希值排序
    }
    
    // 根据缓存键获取缓存服务器
    private function getServer($key)
    {
        $hash = crc32($key); // 使用键的哈希值
        foreach ($this->hashRing as $hashKey => $server) {
            if ($hashKey >= $hash) {
                return $server;
            }
        }
        return reset($this->servers);
    }
    
    // 获取缓存数据
    public function get($key)
    {
        $server = $this->getServer($key);
        // 连接缓存服务器
        $connection = new Memcached();
        $connection->addServer($server, 11211);
        
        $value = $connection->get($key);
        // 关闭连接
        $connection->quit();
        return $value;
    }
    
    // 设置缓存数据
    public function set($key, $value, $expire = 0)
    {
        $server = $this->getServer($key);
        // 连接缓存服务器
        $connection = new Memcached();
        $connection->addServer($server, 11211);
        
        $connection->set($key, $value, $expire);
        // 关闭连接
        $connection->quit();
        return $value;
    }
}

// 示例使用
$servers = ['127.0.0.1', '192.168.1.1', '192.168.2.1'];
$cacheManager = new CacheManager($servers);
$cacheManager->set('key1', 'value1');
$value = $cacheManager->get('key1');
echo $value;