Pool 类

(PECL pthreads >= 2.0.0)

简介

Pool 对象是多个 Worker 对象的容器，同时也是它们的控制器。

线程池是对 Worker 功能的高层抽象，包括按照 pthreads 需要的方式来管理应用的功能。

类摘要

Pool {
/* 属性 */
protected $size ;
protected $class ;
protected $workers ;
protected $ctor ;
protected $last ;
/* 方法 */
public collect ( Callable $collector = ? ) : int
public __construct ( int $size , string $class = ? , array $ctor = ? ) : Pool
publicresize ( int $size ) : void
publicshutdown ( ) : void
public submit ( Threaded $task ) : int
public submitTo ( int $worker , Threaded $task ) : int
}

属性

size

Pool 对象可容纳的 Worker 对象的最大数量

class

Worker 的类

workers

指向 Worker 对象的引用

ctor

构造新的 Worker 对象时所需的参数

last

最后使用的 Worker 对象在池中的位置偏移量

Table of Contents

User Contributed Notes

meadowsjared at gmail dot com 29-Dec-2020 05:43
In this example, it shows how to use a pool to get an array of results, using pThreads v3.2.1 and php 7.3.23

<?php
class TestWork extends Threaded {
//updated version that works with pThreads v3.2.1 and php 7.3.23
    protected $complete;
    //$pData is the data sent to your worker thread to do it's job.
    public function __construct($pData) {
        //transfer all the variables to local variables
        $this->complete = false;
        $this->testData = $pData;
    }
    //This is where all of your work will be done.
    public function run() {
        usleep(2000000); //sleep 2 seconds to simulate a large job
        $this->complete = true;
    }
    public function isDone() {
        return $this->complete;
    }
}
class ExamplePool extends Pool {
    public $data = array(); // used to return data after we're done
    private $numTasks = 0; // counter used to know when we're done
    /**
     * override the submit function from the parent
     * to keep track of our jobs
     */
    public function submit(Threaded $task) {
        $this->numTasks++;
        parent::submit($task);
    }
    /**
     * used to wait until all workers are done
     */
    public function process() {
        // Run this loop as long as we have
        // jobs in the pool
        while (count($this->data) < $this->numTasks) {
            $this->collect(function (TestWork $task) {
                // If a task was marked as done, collect its results
                if ($task->isDone()) {
                    $tmpObj = new stdclass();
                    $tmpObj->complete = $task->complete;
                    //this is how you get your completed data back out [accessed by $pool->process()]
                    $this->data[] = $tmpObj;
                }
                return $task->isDone();
            });
        }
        // All jobs are done
        // we can shutdown the pool
        $this->shutdown();
        return $this->data;
    }
}
$pool = new ExamplePool(3);
$testData = 'asdf';
for($i=0;$i<5;$i++) {
    $pool->submit(new TestWork($testData));
}
$retArr = $pool->process(); //get all of the results
echo '<pre>';
print_r($retArr); //return the array of results (and maybe errors)
echo '</pre>';
?>
meadowsjared at gmail dot com 14-Mar-2016 07:16
Please note, when using the collect function, it's important that you extend the pool class so you can keep checking for finished threads until they're all done.

<?php
class TestWork extends Threaded {
    protected $complete;
    //$pData is the data sent to your worker thread to do it's job.
    public function __construct($pData){
        //transfer all the variables to local variables
        $this->complete = false;
        $this->testData = $pData;
    }
    //This is where all of your work will be done.
    public function run(){
        usleep(2000000); //sleep 2 seconds to simulate a large job
        $this->complete = true;
    }
    public function isGarbage() {
        return $this->complete;
    }
}
class ExamplePool extends Pool
{
    public $data = array();
    public function process()
    {
        // Run this loop as long as we have
        // jobs in the pool
        while (count($this->work)) {
            $this->collect(function (TestWork $task) {
                // If a task was marked as done
                // collect its results
                if ($task->isGarbage()) {
                    $tmpObj = new stdclass();
                    $tmpObj->complete = $task->complete;
                    //this is how you get your completed data back out [accessed by $pool->process()]
                    $this->data[] = $tmpObj;
                }
                return $task->isGarbage();
            });
        }
        // All jobs are done
        // we can shutdown the pool
        $this->shutdown();
        return $this->data;
    }
}
$pool = new ExamplePool(3);
$testData = 'asdf';
for($i=0;$i<5;$i++) {
    $pool->submit(new TestWork($testData));
}
$retArr = $pool->process(); //get all of the results
echo '<pre>';
print_r($retArr); //return the array of results (and maybe errors)
echo '</pre>';
?>
olavk 30-Mar-2015 01:48
Simple example with Collectable (basically Thread meant for Pool) and Pool

<?php

class job extends Collectable {
  public $val;

  public function __construct($val){
    // init some properties
    $this->val = $val;
  }
  public function run(){
    // do some work
    $this->val = $this->val . file_get_contents('http://www.example.com/', null, null, 3, 20);
    $this->setGarbage();
  }
}

// At most 3 threads will work at once
$p = new Pool(3);

$tasks = array(
  new job('0'),
  new job('1'),
  new job('2'),
  new job('3'),
  new job('4'),
  new job('5'),
  new job('6'),
  new job('7'),
  new job('8'),
  new job('9'),
  new job('10'),
);
// Add tasks to pool queue
foreach ($tasks as $task) {
  $p->submit($task);
}

// shutdown will wait for current queue to be completed
$p->shutdown();
// garbage collection check / read results
$p->collect(function($checkingTask){
  echo $checkingTask->val;
  return $checkingTask->isGarbage();
});

?>
fajan 28-May-2014 01:18
Example class to demonstrate usage of Pool/Worker mechanism, also to show a few tricks & hints ;)
<?php
class Config extends Threaded{    // shared global object
    protected $val=0, $val2=0;
    protected function inc(){++$this->val;}    // protected synchronizes by-object
    public function inc2(){++$this->val2;}    // no synchronization
}
class WorkerClass extends Worker{
    protected static $worker_id_next = -1;
    protected $worker_id;
    protected $config;
    public function __construct($config){
        $this->worker_id = ++static::$worker_id_next;    // static members are not avalable in thread but are in 'main thread'
        $this->config = $config;
    }
    public function run(){
        global $config;
        $config = $this->config;    // NOTE: setting by reference WON'T work
        global $worker_id;
        $worker_id = $this->worker_id;
        echo "working context {$worker_id} is created!\n";
        //$this->say_config();    // globally synchronized function.
    }
    protected function say_config(){    // 'protected' is synchronized by-object so WON'T work between multiple instances
        global $config;        // you can use the shared $config object as synchronization source.
        $config->synchronized(function() use (&$config){    // NOTE: you can use Closures here, but if you attach a Closure to a Threaded object it will be destroyed as can't be serialized
            var_dump($config);
        });
    }
}
class Task extends Stackable{    // Stackable still exists, it's just somehow dissappeared from docs (probably by mistake). See older version's docs for more details.
    protected $set;
    public function __construct($set){
        $this->set = $set;
    }
    public function run(){
        global $worker_id;
        echo "task is running in {$worker_id}!\n";
        usleep(mt_rand(1,100)*100);
        $config = $this->getConfig();
        $val = $config->arr->shift();
        $config->arr[] = $this->set;
        for ($i = 0 ; $i < 1000; ++$i){
            $config->inc();
            $config->inc2();
        }
    }
    public function getConfig(){
        global $config;    // WorkerClass set this on thread's scope, can be reused by Tasks for additional asynch data source. (ie: connection pool or taskqueue to demultiplexer)
        return $config;
    }
}

$config = new Config;
$config->arr = new \Threaded();
$config->arr->merge(array(1,2,3,4,5,6));
class PoolClass extends Pool{
    public function worker_list(){
        if ($this->workers !== null)
            return array_keys($this->workers);
        return null;
    }
}
$pool = new PoolClass(3, 'WorkerClass', [$config] );
$pool->worker_list();
//$pool->submitTo(0,new Task(-10));    // submitTo DOES NOT try to create worker

$spammed_id = -1;
for ($i = 1; $i <= 100; ++$i){    // add some jobs
    if ($spammed_id == -1 && ($x = $pool->worker_list())!= null && @$x[2]){
        $spammed_id = $x[2];
        echo "spamming worker {$spammed_id} with lots of tasks from now on\n";
    }
    if ($spammed_id != -1 && ($i % 5) == 0)    // every 5th job is routed to one worker, so it has 20% of the total jobs (with 3 workers it should do ~33%, not it has (33+20)%, so only delegate to worker if you plan to do balancing as well... )
        $pool->submitTo($spammed_id,new Task(10*$i));   
    else
        $pool->submit(new Task(10*$i));
}
$pool->shutdown();
var_dump($config); // "val" is exactly 100000, "val2" is probably a bit less
// also: if you disable the spammer, you'll that the order of the "arr" is random.
?>
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