带着问题出发

错误版本1

public function hello2(RequestInterface $request)
    {
        $name = '';
        $channel = new \Swoole\Coroutine\Channel(12);
        for ($i=0;$i<10;$i++){
            co(function () use ($channel,$name){
                $users = Db::select('select count(*) as ct from xxx;');  //  返回array
                foreach($users as $user){
                    $name .= $user->ct;
                }
            });
//            var_dump($channel->pop());
        }
        var_dump($name);
    }

• 这样做是拿不到值的，因为协程是互相独立的所以压根就拿不到值参数的，而且主线程不会等协程，因此为空值，

正确姿势1(通过管道来实现)

public function hello1(RequestInterface $request)
    {
       $data = [];
        $channel = new \Swoole\Coroutine\Channel(12);
        for ($i=0;$i<10;$i++){
            co(function () use ($channel){
                $users = Db::select('select count(*) as ct from xxx;');  //  返回array
                foreach($users as $user){
                    $channel->push($user->ct);
                }
            });
        }
for ($i = 0; $i < 10; $i++)
        {
            // 当通道为空时，会自动挂起当前协程，等待生产者推送数据后，重新调度进来
            $data [] =  $channel->pop();
        }
        var_dump($channel->pop());
    }

正确用法2(通过协程等待)

public function index2()
    {
        $channel = new \Swoole\Coroutine\Channel(10);
        $wg = new \Swoole\Coroutine\WaitGroup();
        $data = [];
        $wg->add(10);
        for ($i=0;$i<10;$i++){
            co(function () use ($channel,$wg,&$data){
                $users = Db::select('select count(*) as ct from t_lease_assets;');  //  返回array
                foreach($users as $user){
                    $data[] = $user->ct;
                }
                $wg->done();
            });
        }
        $wg->wait();

        return $data;
    }

https://www.cnblogs.com/danhuang/archive/2020/07/15/13277498.html //参考文章

• 放入通道中，然后再获取通道参数即可，这里注意要设定channel的个数否则拿不全参数