Php 7.1 + Pecl-event + libevent - 在奇怪的情况下挂起

Question

基于 this answer, I've switched to pecl-event 库。现在我有：

[root]# php -v
PHP 7.1.12 (cli) (built: Nov 22 2017 08:40:02) ( NTS ) Copyright (c) 1997-2017 The PHP Group Zend Engine v3.1.0, Copyright (c) 1998-2017 Zend Technologieswith Zend OPcache v7.1.12, Copyright (c) 1999-2017, by Zend Technologies 
[root]# php --info | grep event
/etc/php.d/event.ini event libevent2 headers version => 2.1.8-stable
[root]# pecl list
Installed packages, channel pecl.php.net:
=========================================
Package Version State
event   2.3.0   stable

下面的例子表现得很奇怪。如果从 runme() 函数内部调用 $loop->run()，它会工作并调用回调。但是如果从 runme() 之外调用 $loop->run()，它就会挂起！

require_once __DIR__.'/../vendor/autoload.php';

$inner = count($argv) > 1;

$loop = new \React\EventLoop\ExtEventLoop();
//$loop = new \React\EventLoop\StreamSelectLoop();

runme($loop, $inner);

if (!$inner) {
    echo "Outer start\n";
    $loop->run();
}

function runme(\React\EventLoop\LoopInterface $loop, $inner)
{
    $contextOpts = [];
    $flags = STREAM_CLIENT_CONNECT | STREAM_CLIENT_ASYNC_CONNECT;
    $context = stream_context_create($contextOpts);
    $socket = stream_socket_client('tcp://127.0.0.1:3306', $errno, $errstr, 0, $flags, $context);
    stream_set_blocking($socket, 0);

    $loop->addWriteStream($socket, function ($socket) use ($loop) {
        echo "done  ".(false === stream_socket_get_name($socket, true) ? 'false' : 'true')."\n";
        $loop->removeWriteStream($socket);
    });

    if ($inner) {
        echo "Inner start\n";
        $loop->run();
    }

    echo "Exit runme\n";
}

运行结果：

[root@vultr Scraper]# php ./tests/test.php --inner
Inner start
done  false
Exit runme
[root@vultr Scraper]# php ./tests/test.php 
Exit runme
Outer start
...............HANGING HERE...........

我是不是遗漏了什么，或者这是 libraries/PHP 之一的问题？有人有运行 php7.1 + react + libevent 的经验吗？

更新：=========================================== =========================

我用最新的 "react/socket" 库“0.8.6”进行了测试。

require_once __DIR__.'/vendor/autoload.php';

$inner = count($argv) > 1;

$loop = new \React\EventLoop\ExtEventLoop();

$connector = new React\Socket\Connector($loop);

runme($loop, $connector, $inner);

if (!$inner) {
    echo "Outer start\n";
    $loop->run();
}

function runme(\React\EventLoop\LoopInterface $loop, React\Socket\Connector $connector, $inner)
{
    $connector->connect('tcp://127.0.0.1:3306')->
    then(function (\React\Socket\ConnectionInterface $conn) {
        echo ("Hello MySQL!\n");
        $conn->close();
    },function ($e) {
        echo ("Bye MySQL!\n");
    })->done();

    if ($inner) {
        echo "Inner start\n";
        $loop->run();
    }

    echo "Exit runme\n";
}

它工作正常并且returns：

$ php ./testMysql.php 
Exit runme
Outer start
Hello MySQL!
$ php ./testMysql.php  --inner
Inner start
Hello MySQL!
Exit runme

但是如果你进入 \React\Socket\TcpConnector::waitForStreamOnce() 并删除新 Promise 对象中的 $canceller 函数，如下所示，它将再次挂起。看起来它在最新版本的 React 中工作是一种意外，因为套接字没有以明显的方式存储，实际上类似于 v0.4.6 中的代码。

private function waitForStreamOnce($stream)
    {
        $loop = $this->loop;

        return new Promise\Promise(function ($resolve, $reject) use ($loop, $stream) {
            $loop->addWriteStream($stream, function ($stream) use ($loop, $resolve, $reject) {
                $loop->removeWriteStream($stream);

                // The following hack looks like the only way to
                // detect connection refused errors with PHP's stream sockets.
                if (false === stream_socket_get_name($stream, true)) {
                    fclose($stream);

                    $reject(new \RuntimeException('Connection refused'));
                } else {
                    $resolve(new Connection($stream, $loop));
                }
            });
        });
    }



$ php ./testMysql.php  --inner
Inner start
.....HANGING
$ php ./testMysql.php 
Exit runme
Outer start
...HANGING

Answer 1

嘿 ReactPHP 核心开发人员，刚刚查看了您的脚本，我可以在本地重现它，所以我将为此提交一个问题（即使这可能超出我们的范围）。

require_once __DIR__.'/../vendor/autoload.php';

$inner = count($argv) > 1;

$loop = new \React\EventLoop\ExtEventLoop();
//$loop = new \React\EventLoop\StreamSelectLoop();

runme($loop, $inner);

    $contextOpts = [];
    $flags = STREAM_CLIENT_CONNECT | STREAM_CLIENT_ASYNC_CONNECT;
    $context = stream_context_create($contextOpts);
    $socket = stream_socket_client('tcp://127.0.0.1:3306', $errno, $errstr, 0, $flags, $context);
    stream_set_blocking($socket, 0);

    $loop->addWriteStream($socket, function ($socket) use ($loop) {
        echo "done  ".(false === stream_socket_get_name($socket, true) ? 'false' : 'true')."\n";
        $loop->removeWriteStream($socket);
    });

    if ($inner) {
        echo "Inner start\n";
        $loop->run();
    }

    echo "Exit runme\n";

但我建议您查看我们的 socket component 来处理连接。

可能看起来像：

$loop = new \React\EventLoop\ExtEventLoop();
$connector = new React\Socket\Connector($loop);

$connector->connect('tcp://127.0.0.1:3306')->then(function (ConnectionInterface $conn) use ($loop) {
    $conn->write("Hello MySQL!\n");
});

$loop->run();

Answer 2

问题是 $socket 变量 destroyed 当 runme() returns（就像任何本地 PHP 变量一样！）。结果，在此套接字 上打开的连接已关闭 。

事件扩展尽最大努力防止内存泄漏，因此它尽可能不存储对用户变量的引用。特别是，所有方法都接受来自输入变量的 socket resource (Event::__construct, for instance) only retrieve 底层数字文件描述符。用户实际上负责保持那些变量存活 .

以下脚本通过将 $socket 移至全局范围解决了该问题。

require_once 'vendor/autoload.php';

$inner = count($argv) > 1;
$loop = new \React\EventLoop\ExtEventLoop();
$socket = init_socket();

runme($loop, $socket, $inner);

if (!$inner) {
    echo "Outer start\n";
    $loop->run();
}

function init_socket()
{
    $contextOpts = [];
    $flags = STREAM_CLIENT_CONNECT | STREAM_CLIENT_ASYNC_CONNECT;
    $context = stream_context_create($contextOpts);
    $socket = stream_socket_client('tcp://test.local:80', $errno, $errstr, 0, $flags, $context);
    stream_set_blocking($socket, 0);
    return $socket;
}

function runme(\React\EventLoop\LoopInterface $loop, $socket, $inner)
{
    $loop->addWriteStream($socket, function ($socket) use ($loop) {
        echo "done  ".(false === stream_socket_get_name($socket, true) ? 'false' : 'true')."\n";
        $loop->removeWriteStream($socket);
    });

    if ($inner) {
        echo "Inner start\n";
        $loop->run();
    }

    echo "Exit runme\n";
}

在实际应用程序中，您可能会将 $socket 存储为 class 成员变量。

Php 7.1 + Pecl-event + libevent - 在奇怪的情况下挂起

Php 7.1 + Pecl-event + libevent - is hanging in weird case

asynchronous

libevent

reactphp

php-7.1

pecl-event