PHP下用Swoole实现Actor并发模型的方法

什么是actor？

actor对于phper来说，可能会比较陌生，写过java的同学会比较熟悉，java一直都有线程的概念（虽然php有pthread,但不普及）,它是一种非共享内存的并发模型，每个actor内的数据独立存在，actor之间通过消息传递的形式进行交互调度，且actor是一种高度抽象化的编程模型，非常适合于游戏、硬件行业。

swoole协程与信箱

得益于swoole4.x，我们可以基于swoole的协程与channel快速实现一个信箱模式调度。模拟代码如下：

use swoole\coroutine\channel;
go(function (){
  //创建十个信箱通道
  $mailboxes = [];
  for ($i = 1;$i <= 10;$i++){
    $mailboxes[$i] = new channel(16);
  }
  //模拟master 邮局调度,随机像一个信箱投递消息
  go(function ()use($mailboxes){
    while (1){
      \co::sleep(2);
      $key = rand(1,10);
      ($mailboxes[$key])->push(time());
    }
  });
  //模拟actor 实体消费
  for ($i = 1;$i <= 10;$i++){
    go(function ()use($mailboxes,$i){
      while (1){
        $msg = ($mailboxes[$i])->pop();
        echo "actor {$i} recv msg : {$msg} \n";
      }
    });
  }
});

以上代码执行输出：

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

协程通道每次在pop遇到无数据的时候，都会自动让出执行权（具体可以去看swoole协程调度）

actor库

基于上面的原理，我们实行了一个多进程分布的协程actor库

composer require easyswoole/actor=2.x-dev

我们依赖dev库进行测试，生产可以自己依赖stable版本

进程关系

easyswoole的actor模型中，存在两组进程，一组是proxy进程，用来实现actor对外服务，一组是worker进程，proxy进程与worker进程之间通过unixsock进行通讯，而actor实例就均匀的分布worker之中。

样例代码

比如在一个聊天室中，我们可以定义一个房间模型。

namespace easyswoole\actor\test;


use easyswoole\actor\abstractactor;
use easyswoole\actor\actorconfig;

class roomactor extends abstractactor
{
  public static function configure(actorconfig $actorconfig)
  {
    $actorconfig->setactorname('room');
  }
  public function onstart()
  {
    //每当一个roomactor实体被创建的时候，都会执行该回调
    var_dump('room actor '.$this->actorid().' start');
  }
  public function onmessage($msg)
  {
    //每当一个roomactor实体收到外部消息的时候，都会执行该回调当
    var_dump('room actor '.$this->actorid().' onmessage: '.$msg);
    return 'reply at '.time();
  }
  public function onexit($arg)
  { 
    //每当一个roomactor实体退出的时候，都会执行该回调
    var_dump('room actor '.$this->actorid().' exit at arg: '.$arg);
    return 'exit at '.time();
  }
  protected function onexception(\throwable $throwable)
  {
    //每当一个roomactor出现异常的时候，都会执行该回调
    var_dump($throwable->getmessage());
  }
}

在cli模式下创建一个actor服务

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";
}

创建一个cli测试脚本

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'));
});

以上代码执行结果如下：

服务端

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"

客户端

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)

更多细节可以在easyswoole项目官网得到文档支持

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