摘要：協程與信箱得益于，我們可以基于的協程與快速實現一個信箱模式調度。樣例代碼比如在一個聊天室中，我們可以定義一個房間模型。

Actor對于PHPer來說，可能會比較陌生，寫過Java的同學會比較熟悉，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并發模型，每個Actor內的數據獨立存在，Actor之間通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，非常適合于游戲、硬件行業。

得益于Swoole4.x，我們可以基于Swoole的協程與Channel快速實現一個信箱模式調度。模擬代碼如下：

use SwooleCoroutineChannel;
go(function (){
    //創建十個信箱通道
    $mailBoxes = [];
    for ($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} 
";
            }
        });
    }
});

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（具體可以去看Swoole協程調度）

基于上面的原理，我們實行了一個多進程分布的協程Actor庫

composer require easyswoole/actor=2.x-dev

我們依賴dev庫進行測試，生產可以自己依賴stable版本

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進程之間通過unixsock進行通訊，而Actor實例就均勻的分布worker之中。

比如在一個聊天室中，我們可以定義一個房間模型。

namespace EasySwooleActorTest;


use EasySwooleActorAbstractActor;
use EasySwooleActorActorConfig;

class RoomActor extends AbstractActor
{
    public static function configure(ActorConfig $actorConfig)
    {
        $actorConfig->setActorName("Room");
    }
    public function onStart()
    {
        //每當一個RoomActor實體被創建的時候，都會執行該回調
        var_dump("room actor ".$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模式下創建一個Actor服務

use EasySwooleActorActor;
use EasySwooleActorTestRoomActor;
use EasySwooleActorProxyProcess;

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 = SwooleProcess::wait()) {
    echo "PID={$ret["pid"]}
";
}

創建一個cli測試腳本

use EasySwooleActorActor;
use EasySwooleActorTestRoomActor;
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"));
});

以上代碼執行結果如下：
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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