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Implementation of PHP multitask second timer

2022-07-26 05:58:00 【lxw1844912514】

1. describe

Recently deployed in the company crontab When , Whether the sudden whim can be used PHP To implement a timer , It's good if the particle size reaches the second level , because crontab Up to minute level , At the same time, I also investigated and used PHP There aren't too many timers to implement ,Swoole It is extended to realize a millisecond timer, which is very efficient , But after all, it's not pure PHP It's written in code , So finally, consider using PHP To implement a timer class , For learning reference .

2. Code implementation

When implementing timer code , Yes PHP Two extensions of the system

Pcntl - Multi process extension :

Mainly let PHP Many child processes can be started at the same time , Handle some tasks in parallel .

Spl - SplMinHeap - Small cap pile

A small top heap data structure , When implementing the timer , The efficiency of this structure is good , Insert 、 The time complexity of deletion is O(logN) , image libevent The timer is also 1.4 This data structure was adopted after the version, and before that rbtree, If you use a linked list or a fixed array , Insert... Every time 、 Deleting may require re traversal or sorting , There are still some performance problems .

3. technological process

explain

1、 Define timer structure , What parameters are there .
2、 Then register all of them into our timer class Timer.
3、 Call the timer class monitor Method , Start listening .
4、 The monitoring process is a while Dead cycle , Keep looking to see if the top of the time pile has expired , Originally, I thought about watching it every second , Later, when I thought about looking at it every second, I still had a problem , If it happens to be us sleep(1) The timer has expired , Then we can't implement it accurately right away , There may be a risk of delay , So we still use usleep(1000) Millisecond level to see and can also suspend the process to reduce CPU load .

4. Code

<?php

/**** Class Timer*/
class Timer extends SplMinHeap
{
    /**
     *  Compare the size of the root node and the newly inserted node   
     * @param mixed $value1 
     * @param mixed $value2  
     * @return int 
     */
    protected function compare($value1, $value2)
    {
        if ($value1['timeout'] > $value2['timeout']) {
            return -1;
        }
        if ($value1['timeout'] < $value2['timeout']) {
            return 1;
        }
        return 0;
    }

    /**  
     *  Insert node   
     * @param mixed $value 
     */
    public function insert($value)
    {
        $value['timeout'] = time() + $value['expire'];
        parent::insert($value);
    }

    /**
     *  monitor   
     * @param bool $debug 
     */
    public function monitor($debug = false)
    {
        while (!$this->isEmpty()) {
            $this->exec($debug);
            usleep(1000);
        }
    }

    /**  
     *  perform   
     * @param $debug 
     */
    private function exec($debug)
    {
        $hit = 0;
        $t1 = microtime(true);
        while (!$this->isEmpty()) {
            $node = $this->top();
            if ($node['timeout'] <= time()) {        // Out of the pile or into the pile 
                $node['repeat'] ? $this->insert($this->extract()) : $this->extract();
                $hit = 1;        // Start subprocess 
                if (pcntl_fork() == 0) {
                    empty($node['action']) ? '' : call_user_func($node['action']);
                    exit(0);
                }
                // Ignore child processes , Subprocess exit is recycled by the system 
                pcntl_signal(SIGCLD, SIG_IGN);
            } else {
                break;
            }
        }
        $t2 = microtime(true);
        echo ($debug && $hit) ? ' Time pile  -  Adjustment time : ' . round($t2 - $t1, 3) . " second \r\n" : '';
    }
}

5. example

<?php
$timer = new Timer();
// register  - 3s -  Repeat trigger 
$timer->insert(array('expire' => 3, 'repeat' => true, 'action' => function () {
    echo '3 second  -  repeat  - hello world' . "\r\n";
}));

// register  - 3s -  Repeat trigger 
$timer->insert(array('expire' => 3, 'repeat' => true, 'action' => function () {
    echo '3 second  -  repeat  - gogo' . "\r\n";
}));

// register  - 6s -  Trigger once 
$timer->insert(array('expire' => 6, 'repeat' => false, 'action' => function () {
    echo '6 second  -  once  - hello xxxx' . "\r\n";
}));

// monitor 
$timer->monitor(false)

6. Execution results