Redis 实战

Redis的使用场景测试用例

准备

• RedisController.php

<?php

namespace App\Api\Controller;

use App\Api\Controller as BaseController;
use App\Support\RedisTool;
use Collective\Annotations\Routing\Annotations\Annotations\{
    Controller, Post
};

/**
 * Class RedisController
 * @package App\Api\Controller
 * @Controller(prefix="/api/redis")
 */
class RedisController extends BaseController
{
    private $redis;

    public function __construct()
    {
        $this->redis = RedisTool::getInstance();
    }
}

• RedisTool.php

<?php

namespace App\Support;

use App\Concerns\Singleton;
use Illuminate\Support\Facades\Log;

class RedisTool extends \Redis
{
    use Singleton;

    public function __construct()
    {
        parent::__construct();

        $host = config('database.redis.default.host');
        $port = config('database.redis.default.port');

        if (! $this->connect($host, $port)) {
            Log::error("redis fail to connect to $host:$port");
        }
    }
}

• Singleton.php

<?php

namespace App\Concerns;

trait Singleton
{
    public static function getInstance()
    {
        static $instance = null;

        if (is_null($instance)) {
            $instance = new static();
        }

        return $instance;
    }
}

基于 redis 字符串 string 类型的简单缓存

/**
 * @Post("/test_string")
 */
public function test_string()
{
    $this->redis->set('cache_key', json_encode([
        'data-list' => '这是个缓存数据'
    ]), JSON_UNESCAPED_UNICODE);

    $res = $this->redis->get('cache_key');
    var_dump($res);
}

基于 redis 列表 list 类型的简单队列

/**
 * 实现队列
 * @Post("/test_queue")
 */
public function test_queue()
{
    // 进队列
    $user_id = mt_rand(100000, 999999);
    $this->redis->rPush('queue_name', json_encode(['user_id' => $user_id]));
    $user_id = mt_rand(100000, 999999);
    $this->redis->rPush('queue_name', json_encode(['user_id' => $user_id]));
    $user_id = mt_rand(100000, 999999);
    $this->redis->rPush('queue_name', json_encode(['user_id' => $user_id]));

    echo "数据进队列成功 \n";

    // 查看队列
    $res = $this->redis->lRange('queue_name', 0, 100);
    echo "当前队列数据为: \n";
    print_r($res);

    // 出队列
    $this->redis->lPop('queue_name');
    echo "数据出队列成功 \n";

    // 查看队列
    $res = $this->redis->lRange('queue_name', 0, 100);
    echo "当前队列数据为: \n";
    print_r($res);
}

基于 redis 字符串 setnx 的悲观锁

/**
 * 实现悲观锁机制
 * @Post("/test_lock_pessimism")
 */
public function test_lock_pessimism()
{
    $timeout = 5000;
    do {
        $microtime    = microtime(true) * 1000;
        $microtimeout = $microtime + $timeout + 1;

        // 上锁
        $isLock = $this->redis->setnx('lock.count', $microtimeout);
        if (!$isLock) {
            $getTime = $this->redis->get('lock.count');
            if ($getTime > $microtime) {
                // 睡眠, 降低抢锁频率 缓解redis压力
                usleep(5000);
                // 未超时继续等待
                continue;
            }
            // 超时, 抢锁, 可能有几毫秒级时间差可忽略
            $previousTime = $this->redis->getSet('lock.count', $microtimeout);
            if ((int)$previousTime < $microtime) {
                break;
            }
        }

    } while (!$isLock);

    $count = $this->redis->get('count') ?: 0;

    // 业务逻辑
    echo "执行count加1操作~~\n\n";

    $this->redis->set('count', $count + 1);

    // 删除锁
    $this->redis->del('lock.count');
    // 打印count值
    $count = $this->redis->get('count');

    echo "count值为: $count\n";
}

基于 redis 事务的乐观锁

/**
 * 实现悲观锁机制
 * @Post("/test_lock_optimistic")
 */
public function test_lock_optimistic()
{
    // 监视count值
    $this->redis->watch('count');

    // 开启事务(Redis的事务和MySQL事务概念不一样)
    $this->redis->multi();

    // 操作count
    $time = time();
    $this->redis->set('count', $time);

    // 模拟并发下其他进程进行set count操作 请执行下面操作
    // $this->redis->set('count', 'is simulate');
    sleep(10);

    // 提交事务
    $res = $this->redis->exec();

    if ($res) {
        // 成功
        echo 'Success: ' . $time . "\n";
        return;
    }

    // 失败
    echo 'Fail: ' . $time . "\n";
}

基于 redis 的发布订阅

/**
 * 发布
 * @Post("/test_publish")
 */
public function test_publish()
{
    $this->redis->publish('msg', '来自MSG频道的推送');
    echo "MSG频道消息推送成功 \n";
    $this->redis->close();
}

/**
 * 订阅
 * @Post("/test_subscribe")
 */
public function test_subscribe()
{
    // ini_set('default_socket_timeout', -1);

    echo "订阅MSG频道, 等待消息推送...\n";

    $callback = function ($msg) {
        echo $msg;
    };

    $this->redis->subscribe(['msg'], $callback);
}