PHP下用Swoole實現Actor併發模型

什麼是Actor？

Actor對於PHPer來講，可能會比較陌生，寫過Java的同窗會比較熟悉，Java一直都有線程的概念（雖然PHP有Pthread,但不普及）,它是一種非共享內存的併發模型，每一個Actor內的數據獨立存在，Actor之間經過消息傳遞的形式進行交互調度，且Actor是一種高度抽象化的編程模型，很是適合於遊戲、硬件行業。

Swoole協程與信箱

得益於Swoole4.x，咱們能夠基於Swoole的協程與Channel快速實現一個信箱模式調度。模擬代碼以下：

use Swoole\Coroutine\Channel;
go(function (){
    //建立十個信箱通道
    $mailBoxes = [];
    for ($i = 1;$i <= 10;$i++){
        $mailBoxes[$i] = new Channel(16);
    }
    //模擬master 郵局調度,隨機像一個信箱投遞消息
    go(function ()use($mailBoxes){
        while (1){
            \co::sleep(2);
            $key = rand(1,10);
            ($mailBoxes[$key])->push(time());
        }
    });
    //模擬actor 實體消費
    for ($i = 1;$i <= 10;$i++){
        go(function ()use($mailBoxes,$i){
            while (1){
                $msg = ($mailBoxes[$i])->pop();
                echo "Actor {$i} recv msg : {$msg} \n";
            }
        });
    }
});

以上代碼執行輸出：

php test.php 
Actor 8 recv msg : 1559622691 
Actor 10 recv msg : 1559622693 
Actor 1 recv msg : 1559622695 
Actor 5 recv msg : 1559622697

協程通道每次在POP遇到無數據的時候，都會自動讓出執行權（具體能夠去看Swoole協程調度）

Actor庫

基於上面的原理，咱們實行了一個多進程分佈的協程Actor庫

composer require easyswoole/actor=2.x-dev

咱們依賴dev庫進行測試，生產能夠本身依賴stable版本

進程關係

Easyswoole的Actor模型中，存在兩組進程，一組是proxy進程，用來實現Actor對外服務，一組是worker進程，proxy進程與worker進程之間經過unixsock進行通信，而Actor實例就均勻的分佈worker之中。

樣例代碼

好比在一個聊天室中，咱們能夠定義一個房間模型。

namespace EasySwoole\Actor\Test;


use EasySwoole\Actor\AbstractActor;
use EasySwoole\Actor\ActorConfig;

class RoomActor extends AbstractActor
{
    public static function configure(ActorConfig $actorConfig)
    {
        $actorConfig->setActorName('Room');
    }
    public function onStart()
    {
        //每當一個RoomActor實體被建立的時候，都會執行該回調
        var_dump('room actor '.$this->actorId().' start');
    }
    public function onMessage($msg)
    {
        //每當一個RoomActor實體收到外部消息的時候，都會執行該回調當
        var_dump('room actor '.$this->actorId().' onmessage: '.$msg);
        return 'reply at '.time();
    }
    public function onExit($arg)
    { 
        //每當一個RoomActor實體退出的時候，都會執行該回調
        var_dump('room actor '.$this->actorId().' exit at arg: '.$arg);
        return 'exit at '.time();
    }
    protected function onException(\Throwable $throwable)
    {
        //每當一個RoomActor出現異常的時候，都會執行該回調
        var_dump($throwable->getMessage());
    }
}

在cli模式下建立一個Actor服務

use EasySwoole\Actor\Actor;
use EasySwoole\Actor\Test\RoomActor;
use EasySwoole\Actor\ProxyProcess;

Actor::getInstance()->register(RoomActor::class);
$list = Actor::getInstance()->generateProcess();

foreach ($list['proxy'] as  $proxy){
    /** @var ProxyProcess $proxy */
    $proxy->getProcess()->start();
}
foreach ($list['worker'] as $actors){
    foreach ($actors as $actorProcess){
        /** @var ProxyProcess $actorProcess */
        $actorProcess->getProcess()->start();
    }
}
while($ret = \Swoole\Process::wait()) {
    echo "PID={$ret['pid']}\n";
}

建立一個cli測試腳本

use EasySwoole\Actor\Actor;
use EasySwoole\Actor\Test\RoomActor;
Actor::getInstance()->register(RoomActor::class);

go(function (){
    $actorId = RoomActor::client()->create('create arg1');
    var_dump($actorId);
    \co::sleep(3);
    var_dump(RoomActor::client()->send($actorId,'this is msg'));
    \co::sleep(3);
    var_dump(RoomActor::client()->exit($actorId,'this is exit arg'));
    \co::sleep(3);
    RoomActor::client()->create('create arg2');
    \co::sleep(3);
    RoomActor::client()->create('create arg3');
    \co::sleep(3);
    var_dump(RoomActor::client()->sendAll('sendAll msg'));
    \co::sleep(3);
    var_dump(RoomActor::client()->status());
    \co::sleep(3);
    var_dump(RoomActor::client()->exitAll('sendAll exit'));
});

以上代碼執行結果以下：
服務端

php test.php 
string(40) "room actor 00101000000000000000001 start"
string(57) "room actor 00101000000000000000001 onmessage: this is msg"
string(64) "room actor 00101000000000000000001 exit at arg: this is exit arg"
string(40) "room actor 00101000000000000000002 start"
string(40) "room actor 00103000000000000000001 start"
string(57) "room actor 00101000000000000000002 onmessage: sendAll msg"
string(57) "room actor 00103000000000000000001 onmessage: sendAll msg"
string(60) "room actor 00101000000000000000002 exit at arg: sendAll exit"
string(60) "room actor 00103000000000000000001 exit at arg: sendAll exit"

客戶端

php test2.php 
string(23) "00101000000000000000001"
string(19) "reply at 1559623925"
string(18) "exit at 1559623928"
bool(true)
array(3) {
  [1]=>
  int(1)
  [2]=>
  int(0)
  [3]=>
  int(1)
}
bool(true)

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