Redis的高级特性与应用场景(二)

Redis::connection('cache')->pipeline(function ($pipe) use ($fn) {
    foreach ($data() as $v) {
        $likeKeyArr[] = sprintf(LiveRooms::REDIS_LIVE_LIKE_PREFIX, $v['id'], $v['start_live_time']);
        $commentKeyArr[] = sprintf(LiveRooms::REDIS_LIVE_COMMENT_PREFIX, $v['id'], $v['start_live_time']);
        $shareKeyArr[] = sprintf(LiveRooms::REDIS_LIVE_SHARE_PREFIX, $v['id'], $v['start_live_time']);
    }
    $pipe->mget($likeKeyArr);
    $pipe->mget($commentKeyArr);
    $pipe->mget($shareKeyArr);
})

del key

PUBLISH __keyspace@0__:key del # 键空间通知
PUBLISH __keyevent@0__:del key # 键事件通知

<?php
class RedisInstance
{
    private $redis;
    public function __construct($host = '127.0.0.1', $port = 6379)
    {
        $this->redis = new Redis();
        $this->redis->connect($host, $port);
    }
    public function expire($key = null, $time = 0)
    {
        return $this->redis->expire($key, $time);
    }
    public function psubscribe($patterns = array(), $callback)
    {
        $this->redis->psubscribe($patterns, $callback);
    }
    public function setOption()
    {
        $this->redis->setOption(\Redis::OPT_READ_TIMEOUT,-1);
    }
}
echo "程序开始执行..\n";
$redis = new RedisInstance();
$redis->setOption();
$redis->psubscribe(array('__keyevent@0__:expired'), 'callback');
//回调
function callback($redis, $pattern, $chan, $msg)
{
    echo "$pattern\n";
    echo "$chan\n";
    echo "$msg\n";
      /*业务逻辑*/
}

set A 100
set B 100
set C 100
watch A
multi
decrby A 50
incrby B 50
# 在exec之前可以启用第二个客户端,对A账号减少50元,查看watch乐观锁机制是否生效
exec   # 这里就会返回 <nil> 因为事务没有执行
get A  # 第二个客户端转账50元 所以最终为 150

<?php
class RedLock
{
    private $retryDelay;
    private $retryCount;
    private $clockDriftFactor = 0.01;
    private $quorum;
    private $servers = array();
    private $instances = array();
    function __construct(array $servers, $retryDelay = 200, $retryCount = 3)
    {
        $this->servers = $servers;
        $this->retryDelay = $retryDelay;
        $this->retryCount = $retryCount;
        $this->quorum  = min(count($servers), (count($servers) / 2 + 1));
    }
    public function lock($resource, $ttl)
    {
        $this->initInstances();
        $token = uniqid();
        $retry = $this->retryCount;
        do {
            $n = 0;
            $startTime = microtime(true) * 1000;
            foreach ($this->instances as $instance) {
                if ($this->lockInstance($instance, $resource, $token, $ttl)) {
                    $n++;
                }
            }
            # Add 2 milliseconds to the drift to account for Redis expires
            # precision, which is 1 millisecond, plus 1 millisecond min drift
            # for small TTLs.
            $drift = ($ttl * $this->clockDriftFactor) + 2;
            $validityTime = $ttl - (microtime(true) * 1000 - $startTime) - $drift;
            if ($n >= $this->quorum && $validityTime > 0) {
                return [
                    'validity' => $validityTime,
                    'resource' => $resource,
                    'token'    => $token,
                ];
            } else {
                foreach ($this->instances as $instance) {
                    $this->unlockInstance($instance, $resource, $token);
                }
            }
            // Wait a random delay before to retry
            $delay = mt_rand(floor($this->retryDelay / 2), $this->retryDelay);
            usleep($delay * 1000);
            $retry--;
        } while ($retry > 0);
        return false;
    }
    public function unlock(array $lock)
    {
        $this->initInstances();
        $resource = $lock['resource'];
        $token    = $lock['token'];
        foreach ($this->instances as $instance) {
            $this->unlockInstance($instance, $resource, $token);
        }
    }
    private function initInstances()
    {
        if (empty($this->instances)) {
            foreach ($this->servers as $server) {
                list($host, $port, $timeout) = $server;
                $redis = new \Redis();
                $redis->connect($host, $port, $timeout);
                $this->instances[] = $redis;
            }
        }
    }
    private function lockInstance($instance, $resource, $token, $ttl)
    {
        return $instance->set($resource, $token, ['NX', 'PX' => $ttl]);
    }
    private function unlockInstance($instance, $resource, $token)
    {
        $script = '
            if redis.call("GET", KEYS[1]) == ARGV[1] then
                return redis.call("DEL", KEYS[1])
            else
                return 0
            end
        ';
        return $instance->eval($script, [$resource, $token], 1);
    }
}
$servers = [
    ['127.0.0.1', 6379, 0.01],
    ['127.0.0.1', 6389, 0.01],
    ['127.0.0.1', 6399, 0.01],
];
$redLock = new RedLock($servers);
while (true) {
    $lock = $redLock->lock('test', 10000);
    if ($lock) {
        print_r($lock);
    } else {
        print "Lock not acquired\n";
    }
}