一个简单的php守护进程代码示例

工作中同事需要做一个简单的工作进程，需要在进程结束时不能被硬生生的掐断当前正在执行的工作流程，需要等一个处理流程跑完了再结束，所以这时候就需要用到pcntl的信号量来工作了，主要的设计思路：

捕获系统发给进程的中断的信号量
在handler代码中设置标志位变量
在一个业务循环处理完成之后判断标志位变量，如果接收到过终止请求，则跳出整个工作循环。主要的处理逻辑：

注册绑定函数：

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    protected function regist_sig_handler()
    {
        declare(ticks = 1);
        pcntl_signal(SIGTERM, [$this, 'sig_handler']);
        pcntl_signal(SIGHUP, [$this, 'sig_handler']);
        pcntl_signal(SIGINT, [$this, 'sig_handler']);
    }

在函数中设置标志位：

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protected function sig_handler($signo)
    {
        switch ($signo) {
            case SIGTERM:
            case SIGHUP:
            case SIGINT:
                self::$_MYDAEMON_SHOULD_STOP = true;
                // ...
                break;
        }
    }

构建退出处理函数

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 protected function shouldStop()
    {
        if (self::$_MYDAEMON_SHOULD_STOP) {
            // before exit staff code
            // ...
            return true;
        }

        return false;
    }

在主循环中一次处理完成后判断是否要终止退出

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        while (true) {
            if ($this->shouldStop()) {
                break;
            }
            try {
                $jobStatusInfo = $this->execute([]);
            } catch (Exception $ex) {
                $this->log($ex->getMessage());
            }
            usleep(10);
        }

附上完整代码（loop是示例需要长时间处理的业务逻辑，memoryusage超限也会退出，外部可以由supervisor/daemontools等进程监控程序控制）

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#!/usr/bin/env php
<?php
/**
 * Description
 *
 * @project mydevkit
 * @package mydevkit
 * @author nickfan <nickfan81@gmail.com>
 * @link http://www.axiong.me
 * @version $Id$
 * @lastmodified: 2015-07-08 09:37
 *
 */
@set_time_limit(0);

class myDaemon
{
    const DEBUG = true;
    protected static $_MYDAEMON_SHOULD_STOP = false;
    public static $memLimit = 5242880;
    private $loop = 10;
    protected $logpath = '';

    public function __construct($option = [])
    {
        $option += [
            'loop' => 10,
            'memLimit' => 5242880,
            'logpath' => '/tmp/daemon_kill.log',
        ];
        $this->loop = $option['loop'];
        $this->logpath = $option['logpath'];
        self::$memLimit = $option['memLimit'];
        $this->regist_sig_handler();
    }

    public function __destruct()
    {
        $this->log('worker progress ending...');
    }

    protected function regist_sig_handler()
    {
        declare(ticks = 1);
        pcntl_signal(SIGTERM, [$this, 'sig_handler']);
        pcntl_signal(SIGHUP, [$this, 'sig_handler']);
        pcntl_signal(SIGINT, [$this, 'sig_handler']);
    }

    protected function sig_handler($signo)
    {
        switch ($signo) {
            case SIGTERM:
            case SIGHUP:
            case SIGINT:
                self::$_MYDAEMON_SHOULD_STOP = true;
                $signoStr = '';
                if ($signo == SIGTERM) {
                    $signoStr = 'SIGTERM';
                } elseif ($signo == SIGHUP) {
                    $signoStr = 'SIGHUP';
                } elseif ($signo == SIGINT) {
                    $signoStr = 'SIGINT';
                }
                $content = date('Y-m-d H:i:s') . ' ' . $signoStr . PHP_EOL;
                file_put_contents($this->logpath, $content, FILE_APPEND);
                break;
        }
    }

    protected function shouldStop()
    {
        if (self::$_MYDAEMON_SHOULD_STOP) {
            // before exit staff code
            // ...
            return true;
        }
        return false;
    }

    protected function log()
    {
        $args = func_get_args();
        $retstr = date('[Y-m-d H:i:s] ') . implode(' ', $args) . PHP_EOL;
        if (self::DEBUG == true) {
            echo $retstr;
        } else {
            return $retstr;
        }
    }

    public function execute($data = [])
    {
        $this->log('[EXECUTE] process lot of data.');
        for ($i = 0; $i < $this->loop; $i++) {
            $this->log('step:' . ($i + 1));
            sleep(1);
        }
        return rand(1, $this->loop);
    }

    public function run()
    {
        $this->log('[RUN] worker starting to run ...');
        while (true) {
            if ($this->shouldStop()) {
                break;
            }
            $this->log('processJobData Start ...');
            try {
                $jobStatusInfo = $this->execute([]);
                $this->log('processJobData end with: ' . var_export($jobStatusInfo, true));
                unset($jobStatusInfo);
            } catch (Exception $ex) {
                $this->log($ex->getMessage());
            }
            $memory = memory_get_usage();
            $this->log('memory usage:' . sprintf('%.2fMB', round($memory / 1048576, 2)));
            if ($memory > self::$memLimit) {
                $this->log('exiting run due to memory limit');
                exit;
            }
            //sleep(1);
            usleep(10);
        }
        $this->log('[RUN] worker run quit.');
    }
}

$gotMyParam = 10;
if (isset($argv[1])) {
    $gotMyParam = intval(trim(strip_tags($argv[1])));
}
$worker = new myDaemon(['loop' => $gotMyParam, 'memLimit' => 1048576 * 128,]);
$worker->run();

测试：

在class代码中的构造函数中注释掉

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//$this->regist_sig_handler();

运行daemon代码，在执行execute的for循环时ctrl+c或者用 kill 杀死当前进程

进程直接结束，没有执行完execute的一个完整流程就直接退出了，

把注释去掉重新执行daemon代码：

在执行过程中按ctrl+c或者kill命令杀死前进程

观察daemon运行的结果是直到整个execute循环执行完了以后才退出程序的

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