基于PHP+Redis实现分布式锁

$redis = new \Redis();
$redis->connect('127.0.0.1',6379);
$result = $redis->setNx('key','val');
if ($result) {
	$redis->expire('key',30);
}

$redis = new \Redis();
$redis->connect('127.0.0.1',6379);
$luaScript = <<<LUA
           if redis.call("setnx", KEYS[1], ARGV[1]) == 1 then
               redis.call("expire", KEYS[1], ARGV[2])
               return true
           end
           return false
LUA;

$result = $redis>eval($luaScript,[ $this->lockKey, $this->requestId, $this->expireTime ],1);

//index.php
$redis = new \Redis();
$redis->connect('127.0.0.1',6379);
    
$luaScript = <<<LUA
   return {KEYS[1],KEYS[2],KEYS[3],ARGV[1],ARGV[2]};
LUA;
var_dump($redis->eval($luaScript,[1,2,3,4,5],3));

<?php 
class RedisDistributedLock {
    private $redis;
    private $lockKey;
    private $requestId;
    private $expireTime;
    /**
     * @param string $lockKey    加锁的key
     * @param int    $expireTime 锁的有效期（单位：秒）
     */
    public function __construct(string $lockKey, $expireTime = 30) 
    {
        $redis = new \Redis();
        $redis->connect('127.0.0.1',6379);
        $this->redis      = $redis;
        $this->lockKey    = $lockKey;
        $this->expireTime = $expireTime;
        $this->requestId  = uniqid(); // 生成唯一请求ID
    }
    /**
     * 尝试获取锁，并在指定次数内进行重试
     *
     * @param int $maxRetries 最大重试次数，默认为3次
     * @param int $retryDelay 两次重试之间的延迟时间（单位：毫秒）
     * @return bool 是否成功获取锁
     */
    public function acquireLock(int $maxRetries = 3, int $retryDelay = 50): bool
    {
        
        for ($attempt = 1; $attempt <= $maxRetries; $attempt++) {
            if ($this->acquireLockOnce()) {
                return true;
            }
            usleep($retryDelay * 1000);
        }
        return false;
    }
    /**
     * 进行加锁
     * @return bool 加锁是否成功
     */
    private function acquireLockOnce(): bool 
    {
        $luaScript = <<<LUA
            if redis.call("setnx", KEYS[1], ARGV[1]) == 1 then
                redis.call("expire", KEYS[1], ARGV[2])
                return true
            end
            return false
LUA;

        $result = $this->redis->eval(
            $luaScript,
            [ $this->lockKey, $this->requestId, $this->expireTime ],
            1
        );

        return (bool)$result;
    }
    /**
     * 释放锁
     * @return bool
     */
    public function releaseLock(): bool
    {
        $luaScript = <<<LUA
        if redis.call("get", KEYS[1]) == ARGV[1] then
            return redis.call("del", KEYS[1])
        else
            return 0
        end
LUA;

        $result = $this->redis->eval(
            $luaScript,
            [ $this->lockKey, $this->requestId ],
            1
        );

        return (bool)$result;
    }
}
?>

<?php
include 'RedisDistributedLock.php';
function task() {
    $lockKey = 'task_1';
    $handler = new RedisDistributedLock($lockKey);
    $startTime = time();
    if ($handler->acquireLock(4)) {
        //@TODO 加锁成功后执行具体的业务逻辑
        echo '加锁成功 开始执行加锁逻辑的时间：'.date('Y-m-d H:i:s',$startTime);
        echo "\r\n";
        echo '锁定到：'.date('Y-m-d H:i:s',time() + 15);
        sleep(15);
        $handler->releaseLock();
        echo "\r\n";
        echo '---15s后已释放锁---';
    } else {
        echo '加锁失败：'.date('Y-m-d H:i:s',$startTime);
        return false;
    }
}
task();
?>