php教程 带你学习swoole_process

推荐（免费）：swoole

swoole 的进程之间有两种通信方式，一种是消息队列(queue)，另一种是管道(pipe)，对swoole_process 的研究在swoole中显得尤为重要。

预备知识

IO多路复用

swoole 中的io多路复用表现为底层的 epoll进程模型，在C语言中表现为 epoll 函数。

epoll 模型下会持续监听自己名下的素有socket 描述符 fd
当触发了 socket 监听的事件时，epoll 函数才会响应，并返回所有监听该时间的 socket 集合
epoll 的本质是阻塞IO，它的优点在于能同事处理大量socket连接
Event loop 事件循环

swoole 对 epoll 实现了一个Reactor线程模型封装，设置了read事件和write事件的监听回调函数。（详见swoole_event_add）

Event loop 是一个Reactor线程，其中运行了一个epoll实例。
通过swoole_event_add将socket描述符的一个事件添加到epoll监听中，事件发生时将执行回调函数
不可用于fpm环境下，因为fpm在任务结束时可能会关掉进程。

swoole_process

基于C语言封装的进程管理模块，方便php来调用
内置管道、消息队列接口，方便实现进程间通信
我们在php-fpm.conf配置文件中发现，php-fpm中有两种进程池管理设置。

静态模式 即初始化固定的进程数，当来了一个请求时，从中选取一个进程来处理。
动态模式 指定最小、最大进程数，当请求量过大，进程数不超过最大限制时，新增线程去处理请求

接下来用swoole代码来实现，这里只是为理解swoole_process、进程间通信、定时器等使用，实际情况使用封装好的swoole_server来实现task任务队列池会更方便。

假如有个定时投递的任务队列：

<?php/**
 * 动态进程池，类似fpm
 * 动态新建进程
 * 有初始进程数，最小进程数，进程不够处理时候新建进程，不超过最大进程数
 */// 一个进程定时投递任务/**
 * 1. tick
 * 2. process及其管道通讯
 * 3. event loop 事件循环
 */class processPool{
  private $pool;

  /**
   * @var swoole_process[] 记录所有worker的process对象
   */
  private $workers = [];

  /**
   * @var array 记录worker工作状态
   */
  private $used_workers = [];

  /**
   * @var int 最小进程数
   */
  private $min_woker_num = 5;

  /**
   * @var int 初始进程数
   */
  private $start_worker_num = 10;

  /**
   * @var int 最大进程数
   */
  private $max_woker_num = 20;

  /**
   * 进程闲置销毁秒数
   * @var int
   */
  private $idle_seconds = 5;

  /**
   * @var int 当前进程数
   */
  private $curr_num;

  /**
   * 闲置进程时间戳
   * @var array
   */
  private $active_time = [];

  public function __construct()
  {
    $this->pool = new swoole_process(function () {
      // 循环建立worker进程
      for ($i = 0; $i < $this->start_worker_num; $i++) {
        $this->createWorker();
      }
      echo '初始化进程数：' . $this->curr_num . PHP_EOL;
      // 每秒定时往闲置的worker的管道中投递任务
      swoole_timer_tick(1000, function ($timer_id) {
        static $count = 0;
        $count++;
        $need_create = true;
        foreach ($this->used_workers as $pid => $used) {
          if ($used == 0) {
            $need_create = false;
            $this->workers[$pid]->write($count . ' job');
            // 标记使用中
            $this->used_workers[$pid] = 1;
            $this->active_time[$pid] = time();
            break;
          }
        }
        foreach ($this->used_workers as $pid => $used)
          // 如果所有worker队列都没有闲置的，则新建一个worker来处理
          if ($need_create && $this->curr_num < $this->max_woker_num) {
            $new_pid = $this->createWorker();
            $this->workers[$new_pid]->write($count . ' job');
            $this->used_workers[$new_pid] = 1;
            $this->active_time[$new_pid] = time();
          }

        // 闲置超过一段时间则销毁进程
        foreach ($this->active_time as $pid => $timestamp) {
          if ((time() - $timestamp) > $this->idle_seconds && $this->curr_num > $this->min_woker_num) {
            // 销毁该进程
            if (isset($this->workers[$pid]) && $this->workers[$pid] instanceof swoole_process) {
              $this->workers[$pid]->write('exit');
              unset($this->workers[$pid]);
              $this->curr_num = count($this->workers);
              unset($this->used_workers[$pid]);
              unset($this->active_time[$pid]);
              echo "{$pid} destroyed\n";
              break;
            }
          }
        }

        echo "任务{$count}/{$this->curr_num}\n";

        if ($count == 20) {
          foreach ($this->workers as $pid => $worker) {
            $worker->write('exit');
          }
          // 关闭定时器
          swoole_timer_clear($timer_id);
          // 退出进程池
          $this->pool->exit(0);
          exit();
        }
      });

    });

    $master_pid = $this->pool->start();
    echo "Master $master_pid start\n";

    while ($ret = swoole_process::wait()) {
      $pid = $ret['pid'];
      echo "process {$pid} existed\n";
    }
  }

  /**
   * 创建一个新进程
   * @return int 新进程的pid
   */
  public function createWorker()
  {
    $worker_process = new swoole_process(function (swoole_process $worker) {
      // 给子进程管道绑定事件
      swoole_event_add($worker->pipe, function ($pipe) use ($worker) {
        $data = trim($worker->read());
        if ($data == 'exit') {
          $worker->exit(0);
          exit();
        }
        echo "{$worker->pid} 正在处理 {$data}\n";
        sleep(5);
        // 返回结果，表示空闲
        $worker->write("complete");
      });
    });

    $worker_pid = $worker_process->start();

    // 给父进程管道绑定事件
    swoole_event_add($worker_process->pipe, function ($pipe) use ($worker_process) {
      $data = trim($worker_process->read());
      if ($data == 'complete') {
        // 标记为空闲//        echo "{$worker_process->pid} 空闲了\n";
        $this->used_workers[$worker_process->pid] = 0;
      }
    });

    // 保存process对象
    $this->workers[$worker_pid] = $worker_process;
    // 标记为空闲
    $this->used_workers[$worker_pid] = 0;
    $this->active_time[$worker_pid] = time();
    $this->curr_num = count($this->workers);
    return $worker_pid;
  }}new processPool();

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