[转]php的协程体验

 

————————————————————————————————————————————————————————

上次通过C扩展为PHP添加coroutine尝试失败之后,由于短期内啃下Zend可能性几乎为零,只能打语言原生能力的主意了。Google之后发现,PHP5.5引入了Generator和Coroutine新特性,于是才有了本文的诞生。

背景阅读

《当C/C++后台开发遇上Coroutine》

http://blog.csdn.net/cszhouwei/article/details/14230529

《一次失败的PHP扩展开发之旅》

http://blog.csdn.net/cszhouwei/article/details/41290673

预备知识

Generator

  1.  
    function my_range($start, $end, $step = 1) {
  2.  
    for ($i = $start; $i <= $end; $i += $step) {
  3.  
    yield $i;
  4.  
    }
  5.  
    }
  6.  
     
  7.  
    foreach (my_range(1, 1000) as $num) {
  8.  
    echo $num, "\n";
  9.  
    }
  10.  
    /*
  11.  
    * 1
  12.  
    * 2
  13.  
    * ...
  14.  
    * 1000
  15.  
    */

图 1 基于generator的range()实现

 

  1.  
    $range = my_range(1, 1000);
  2.  
     
  3.  
    var_dump($range);
  4.  
    /*
  5.  
    * object(Generator)#1 (0) {
  6.  
    * }
  7.  
    */
  8.  
     
  9.  
    var_dump($range instanceof Iterator);
  10.  
    /*
  11.  
    * bool(true)
  12.  
    */

 

图 2 my_range()的实现推测

由于接触PHP时日尚浅,并未深入语言实现细节,所以只能根据现象进行猜测,以下是我的一些个人理解:

  • 包含yield关键字的函数比较特殊,返回值是一个Generator对象,此时函数内语句尚未真正执行
  • Generator对象是Iterator接口实例,可以通过rewind()、current()、next()、valid()系列接口进行操纵
  • Generator可以视为一种“可中断”的函数,而yield构成了一系列的“中断点”
  • Generator类似于车间生产的流水线,每次需要用产品的时候才从那里取一个,然后这个流水线就停在那里等待下一次取操作

Coroutine

细心的读者可能已经发现,截至目前,其实Generator已经实现了Coroutine的关键特性:中断执行、恢复执行。按照《当C/C++后台开发遇上Coroutine》的思路,借助“全局变量”一类语言设施进行信息传递,实现异步Server应该足够了。

其实相对于swapcontext族函数,Generator已经前进了一大步,具备了“返回数据”的能力,如果同时具备“发送数据”的能力,就再也不必通过那些蹩脚的手法绕路而行了。在PHP里面,通过Generator的send()接口(注意:不再是next()接口),可以完成“发送数据”的任务,从而实现了真正的“双向通信”。

 

  1.  
    function gen() {
  2.  
    $ret = (yield ‘yield1‘);
  3.  
    echo "[gen]", $ret, "\n";
  4.  
    $ret = (yield ‘yield2‘);
  5.  
    echo "[gen]", $ret, "\n";
  6.  
    }
  7.  
     
  8.  
    $gen = gen();
  9.  
    $ret = $gen->current();
  10.  
    echo "[main]", $ret, "\n";
  11.  
    $ret = $gen->send("send1");
  12.  
    echo "[main]", $ret, "\n";
  13.  
    $ret = $gen->send("send2");
  14.  
    echo "[main]", $ret, "\n";
  15.  
     
  16.  
    /*
  17.  
    * [main]yield1
  18.  
    * [gen]send1
  19.  
    * [main]yield2
  20.  
    * [gen]send2
  21.  
    * [main]
  22.  
    */

 

图 3 Coroutine双向通信示例

作为C/C++系码农,发现“可重入”、“双向通信”能力之后,貌似没有更多奢求了,不过PHP还是比较慷慨,继续添加了Exception机制,“错误处理”机制得到进一步完善。

 

  1.  
    function gen() {
  2.  
    $ret = (yield ‘yield1‘);
  3.  
    echo "[gen]", $ret, "\n";
  4.  
    try {
  5.  
    $ret = (yield ‘yield2‘);
  6.  
    echo "[gen]", $ret, "\n";
  7.  
    } catch (Exception $ex) {
  8.  
    echo "[gen][Exception]", $ex->getMessage(), "\n";
  9.  
    }
  10.  
    echo "[gen]finish\n";
  11.  
    }
  12.  
     
  13.  
    $gen = gen();
  14.  
    $ret = $gen->current();
  15.  
    echo "[main]", $ret, "\n";
  16.  
    $ret = $gen->send("send1");
  17.  
    echo "[main]", $ret, "\n";
  18.  
    $ret = $gen->throw(new Exception("Test"));
  19.  
    echo "[main]", $ret, "\n";
  20.  
     
  21.  
    /*
  22.  
    * [main]yield1
  23.  
    * [gen]send1
  24.  
    * [main]yield2
  25.  
    * [gen][Exception]Test
  26.  
    * [gen]finish
  27.  
    * [main]
  28.  
    */

 

图 4 Coroutine错误处理示例

实战演习

前面简单介绍了相关的语言设施,那么具体到实际项目中,到底应该如何运用呢?让我们继续《一次失败的PHP扩展开发之旅》描述的场景,借助上述特性实现那个美好的愿望:以同步方式书写异步代码!

第一版初稿

 

  1.  
    <?php
  2.  
     
  3.  
    class AsyncServer {
  4.  
    protected $handler;
  5.  
    protected $socket;
  6.  
    protected $tasks = [];
  7.  
     
  8.  
    public function __construct($handler) {
  9.  
    $this->handler = $handler;
  10.  
     
  11.  
    $this->socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
  12.  
    if(!$this->socket) {
  13.  
    die(socket_strerror(socket_last_error())."\n");
  14.  
    }
  15.  
    if (!socket_set_nonblock($this->socket)) {
  16.  
    die(socket_strerror(socket_last_error())."\n");
  17.  
    }
  18.  
    if(!socket_bind($this->socket, "0.0.0.0", 1234)) {
  19.  
    die(socket_strerror(socket_last_error())."\n");
  20.  
    }
  21.  
    }
  22.  
     
  23.  
    public function Run() {
  24.  
    while (true) {
  25.  
    $reads = array($this->socket);
  26.  
    foreach ($this->tasks as list($socket)) {
  27.  
    $reads[] = $socket;
  28.  
    }
  29.  
    $writes = NULL;
  30.  
    $excepts= NULL;
  31.  
    if (!socket_select($reads, $writes, $excepts, 0, 1000)) {
  32.  
    continue;
  33.  
    }
  34.  
     
  35.  
    foreach ($reads as $one) {
  36.  
    $len = socket_recvfrom($one, $data, 65535, 0, $ip, $port);
  37.  
    if (!$len) {
  38.  
    //echo "socket_recvfrom fail.\n";
  39.  
    continue;
  40.  
    }
  41.  
    if ($one == $this->socket) {
  42.  
    //echo "[Run]request recvfrom succ. data=$data ip=$ip port=$port\n";
  43.  
    $handler = $this->handler;
  44.  
    $coroutine = $handler($one, $data, $len, $ip, $port);
  45.  
    $task = $coroutine->current();
  46.  
    //echo "[Run]AsyncTask recv. data=$task->data ip=$task->ip port=$task->port timeout=$task->timeout\n";
  47.  
    $socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
  48.  
    if(!$socket) {
  49.  
    //echo socket_strerror(socket_last_error())."\n";
  50.  
    $coroutine->throw(new Exception(socket_strerror(socket_last_error()), socket_last_error()));
  51.  
    continue;
  52.  
    }
  53.  
    if (!socket_set_nonblock($socket)) {
  54.  
    //echo socket_strerror(socket_last_error())."\n";
  55.  
    $coroutine->throw(new Exception(socket_strerror(socket_last_error()), socket_last_error()));
  56.  
    continue;
  57.  
    }
  58.  
    socket_sendto($socket, $task->data, $task->len, 0, $task->ip, $task->port);
  59.  
    $this->tasks[$socket] = [$socket, $coroutine];
  60.  
    } else {
  61.  
    //echo "[Run]response recvfrom succ. data=$data ip=$ip port=$port\n";
  62.  
    if (!isset($this->tasks[$one])) {
  63.  
    //echo "no async_task found.\n";
  64.  
    } else {
  65.  
    list($socket, $coroutine) = $this->tasks[$one];
  66.  
    unset($this->tasks[$one]);
  67.  
    socket_close($socket);
  68.  
    $coroutine->send(array($data, $len));
  69.  
    }
  70.  
    }
  71.  
    }
  72.  
    }
  73.  
    }
  74.  
    }
  75.  
     
  76.  
    class AsyncTask {
  77.  
    public $data;
  78.  
    public $len;
  79.  
    public $ip;
  80.  
    public $port;
  81.  
    public $timeout;
  82.  
     
  83.  
    public function __construct($data, $len, $ip, $port, $timeout) {
  84.  
    $this->data = $data;
  85.  
    $this->len = $len;
  86.  
    $this->ip = $ip;
  87.  
    $this->port = $port;
  88.  
    $this->timeout = $timeout;
  89.  
    }
  90.  
    }
  91.  
     
  92.  
    function RequestHandler($socket, $req_buf, $req_len, $ip, $port) {
  93.  
    //echo "[RequestHandler] before yield AsyncTask. REQ=$req_buf\n";
  94.  
    list($rsp_buf, $rsp_len) = (yield new AsyncTask($req_buf, $req_len, "127.0.0.1", 2345, 1000));
  95.  
    //echo "[RequestHandler] after yield AsyncTask. RSP=$rsp_buf\n";
  96.  
    socket_sendto($socket, $rsp_buf, $rsp_len, 0, $ip, $port);
  97.  
    }
  98.  
     
  99.  
    $server = new AsyncServer(RequestHandler);
  100.  
    $server->Run();
  101.  
     
  102.  
    ?>

 

代码解读:

  • 为了便于说明问题,这里所有底层通讯基于UDP,省略了TCP的connect等繁琐细节
  • AsyncServer为底层框架类,封装了网络通讯细节以及协程切换细节,通过socket进行coroutine绑定
  • RequestHandler为业务处理函数,通过yield new AsyncTask()实现异步网络交互

第二版完善

第一版遗留问题:

  • 异步网络交互的timeout未实现,仅预留了接口参数
  • yield new AsyncTask()调用方式不够自然,略感别扭
  1.  
    <?php
  2.  
     
  3.  
    class AsyncServer {
  4.  
    protected $handler;
  5.  
    protected $socket;
  6.  
    protected $tasks = [];
  7.  
    protected $timers = [];
  8.  
     
  9.  
    public function __construct(callable $handler) {
  10.  
    $this->handler = $handler;
  11.  
     
  12.  
    $this->socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
  13.  
    if(!$this->socket) {
  14.  
    die(socket_strerror(socket_last_error())."\n");
  15.  
    }
  16.  
    if (!socket_set_nonblock($this->socket)) {
  17.  
    die(socket_strerror(socket_last_error())."\n");
  18.  
    }
  19.  
    if(!socket_bind($this->socket, "0.0.0.0", 1234)) {
  20.  
    die(socket_strerror(socket_last_error())."\n");
  21.  
    }
  22.  
    }
  23.  
     
  24.  
    public function Run() {
  25.  
    while (true) {
  26.  
    $now = microtime(true) * 1000;
  27.  
    foreach ($this->timers as $time => $sockets) {
  28.  
    if ($time > $now) break;
  29.  
    foreach ($sockets as $one) {
  30.  
    list($socket, $coroutine) = $this->tasks[$one];
  31.  
    unset($this->tasks[$one]);
  32.  
    socket_close($socket);
  33.  
    $coroutine->throw(new Exception("Timeout"));
  34.  
    }
  35.  
    unset($this->timers[$time]);
  36.  
    }
  37.  
     
  38.  
    $reads = array($this->socket);
  39.  
    foreach ($this->tasks as list($socket)) {
  40.  
    $reads[] = $socket;
  41.  
    }
  42.  
    $writes = NULL;
  43.  
    $excepts= NULL;
  44.  
    if (!socket_select($reads, $writes, $excepts, 0, 1000)) {
  45.  
    continue;
  46.  
    }
  47.  
     
  48.  
    foreach ($reads as $one) {
  49.  
    $len = socket_recvfrom($one, $data, 65535, 0, $ip, $port);
  50.  
    if (!$len) {
  51.  
    //echo "socket_recvfrom fail.\n";
  52.  
    continue;
  53.  
    }
  54.  
    if ($one == $this->socket) {
  55.  
    //echo "[Run]request recvfrom succ. data=$data ip=$ip port=$port\n";
  56.  
    $handler = $this->handler;
  57.  
    $coroutine = $handler($one, $data, $len, $ip, $port);
  58.  
    if (!$coroutine) {
  59.  
    //echo "[Run]everything is done.\n";
  60.  
    continue;
  61.  
    }
  62.  
    $task = $coroutine->current();
  63.  
    //echo "[Run]AsyncTask recv. data=$task->data ip=$task->ip port=$task->port timeout=$task->timeout\n";
  64.  
    $socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
  65.  
    if(!$socket) {
  66.  
    //echo socket_strerror(socket_last_error())."\n";
  67.  
    $coroutine->throw(new Exception(socket_strerror(socket_last_error()), socket_last_error()));
  68.  
    continue;
  69.  
    }
  70.  
    if (!socket_set_nonblock($socket)) {
  71.  
    //echo socket_strerror(socket_last_error())."\n";
  72.  
    $coroutine->throw(new Exception(socket_strerror(socket_last_error()), socket_last_error()));
  73.  
    continue;
  74.  
    }
  75.  
    socket_sendto($socket, $task->data, $task->len, 0, $task->ip, $task->port);
  76.  
    $deadline = $now + $task->timeout;
  77.  
    $this->tasks[$socket] = [$socket, $coroutine, $deadline];
  78.  
    $this->timers[$deadline][$socket] = $socket;
  79.  
    } else {
  80.  
    //echo "[Run]response recvfrom succ. data=$data ip=$ip port=$port\n";
  81.  
    list($socket, $coroutine, $deadline) = $this->tasks[$one];
  82.  
    unset($this->tasks[$one]);
  83.  
    unset($this->timers[$deadline][$one]);
  84.  
    socket_close($socket);
  85.  
    $coroutine->send(array($data, $len));
  86.  
    }
  87.  
    }
  88.  
    }
  89.  
    }
  90.  
    }
  91.  
     
  92.  
    class AsyncTask {
  93.  
    public $data;
  94.  
    public $len;
  95.  
    public $ip;
  96.  
    public $port;
  97.  
    public $timeout;
  98.  
     
  99.  
    public function __construct($data, $len, $ip, $port, $timeout) {
  100.  
    $this->data = $data;
  101.  
    $this->len = $len;
  102.  
    $this->ip = $ip;
  103.  
    $this->port = $port;
  104.  
    $this->timeout = $timeout;
  105.  
    }
  106.  
    }
  107.  
     
  108.  
    function AsyncSendRecv($req_buf, $req_len, $ip, $port, $timeout) {
  109.  
    return new AsyncTask($req_buf, $req_len, $ip, $port, $timeout);
  110.  
    }
  111.  
     
  112.  
    function RequestHandler($socket, $req_buf, $req_len, $ip, $port) {
  113.  
    //echo "[RequestHandler] before yield AsyncTask. REQ=$req_buf\n";
  114.  
    try {
  115.  
    list($rsp_buf, $rsp_len) = (yield AsyncSendRecv($req_buf, $req_len, "127.0.0.1", 2345, 3000));
  116.  
    } catch (Exception $ex) {
  117.  
    $rsp_buf = $ex->getMessage();
  118.  
    $rsp_len = strlen($rsp_buf);
  119.  
    //echo "[Exception]$rsp_buf\n";
  120.  
    }
  121.  
    //echo "[RequestHandler] after yield AsyncTask. RSP=$rsp_buf\n";
  122.  
    socket_sendto($socket, $rsp_buf, $rsp_len, 0, $ip, $port);
  123.  
    }
  124.  
     
  125.  
    $server = new AsyncServer(RequestHandler);
  126.  
    $server->Run();
  127.  
     
  128.  
    ?>

代码解读:

  • 借助PHP内置array能力,实现简单的“超时管理”,以毫秒为精度作为时间分片
  • 封装AsyncSendRecv接口,调用形如yield AsyncSendRecv(),更加自然
  • 添加Exception作为错误处理机制,添加ret_code亦可,仅为展示之用

性能测试

测试环境

[转]php的协程体验

测试数据

  100Byte/REQ 1000Byte/REQ
async_svr_v1.php 16000/s 15000/s
async_svr_v2.php 11000/s 10000/s

展望未来

  • 有兴趣的PHPer可以基于该思路进行底层框架封装,对于常见阻塞操作进行封装,比如:connect、send、recv、sleep ...
  • 本人接触PHP时日尚浅,很多用法非最优,高手可有针对性优化,性能应该可以继续提高
  • 目前基于socket进行coroutine绑定,如果基于TCP通信,每次connect/close,开销过大,需要考虑实现连接池
  • python等语言也有类似的语言设施,有兴趣的读者可以自行研究

[转]php的协程体验

原文:https://www.cnblogs.com/oxspirt/p/14008832.html

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