php多进程总结

/** 确保这个函数只能运行在SHELL中 */
if (substr(php_sapi_name(), 0, 3) !== ‘cli‘) {
　　die("cli mode only");
}

<?php

//最大的子进程数量
$maxChildPro = 8;

//当前的子进程数量
$curChildPro = 0;

//当子进程退出时，会触发该函数,当前子进程数-1
function sig_handler($sig)
{
    global $curChildPro;
    switch ($sig) {
        case SIGCHLD:
            echo ‘SIGCHLD‘, PHP_EOL;
            $curChildPro--;
            break;
    }
}

//配合pcntl_signal使用，简单的说，是为了让系统产生时间云，让信号捕捉函数能够捕捉到信号量
declare(ticks = 1);

//注册子进程退出时调用的函数。SIGCHLD：在一个进程终止或者停止时，将SIGCHLD信号发送给其父进程。
pcntl_signal(SIGCHLD, "sig_handler");

while (true) {
    $curChildPro++;
    $pid = pcntl_fork();
    if ($pid) {
//父进程运行代码,达到上限时父进程阻塞等待任一子进程退出后while循环继续
        if ($curChildPro >= $maxChildPro) {
            pcntl_wait($status);
        }
    } else {
//子进程运行代码
        $s = rand(2, 6);
        sleep($s);
        echo "child sleep $s second quit", PHP_EOL;
        exit;
    }
}

<?php

$childs = array();

// Fork10个子进程
for ($i = 0; $i < 10; $i++) {
    $pid = pcntl_fork();
    if ($pid == -1)
        die(‘Could not fork‘);

    if ($pid) {
        echo "parent \n";
        $childs[] = $pid;
    } else {
// Sleep $i+1 (s). 子进程可以得到$i参数
        sleep($i + 1);

// 子进程需要exit,防止子进程也进入for循环
        exit();
    }
}

while (count($childs) > 0) {
    foreach ($childs as $key => $pid) {
        $res = pcntl_waitpid($pid, $status, WNOHANG);

//-1代表error, 大于0代表子进程已退出,返回的是子进程的pid,非阻塞时0代表没取到退出子进程
        if ($res == -1 || $res > 0)
            unset($childs[$key]);
    }

    sleep(1);
}

<?php
function _fetchLog()
{
    $password        = $this->_getPassword();
    $online_log_path = NginxConf::getArchiveDir($this->_stat_day);
    $task_log_path   = QFrameConfig::getConfig(‘LOG_PATH‘);
    $children        = array();
    $success         = true;
    foreach($this->_server_list as $host => $value)
    {
        $local_dir = $this->_prepareLocalDir($host);
        $task_log  = "$task_log_path/fetch_log.$host";
        $cmd = "sshpass -p $password rsync -av -e ‘ssh -o StrictHostKeyChecking=no‘ $host:$online_log_path/* $local_dir >> $task_log 2>&1";
        $pid = pcntl_fork();
        if(-1 === $pid)
        {
            LogSvc::log(‘stat_pv_by_citycode_error‘, ‘could not fork‘);
            exit(‘could not fork‘);
        }
        else if(0 === $pid)
        {
            system($cmd, $return_value);
            if(0 !== $return_value)
            {
                LogSvc::log(‘stat_pv_by_citycode_error‘, "rsync $host error");
            }
            exit($return_value);
        }
        else
        {
            $children[$pid] = 1;
        }
    }
    while(!empty($children))
    {
        $pid = pcntl_waitpid(-1, $status, WNOHANG);
        if(0 === $pid)
        {
            sleep(1);
        }
        else
        {
            if(0 !== pcntl_wexitstatus($status))
            {
                $success = false;
            }
            unset($children[$pid]);
        }
    }
    return $success;
}