php 守护进程（Daemon）

守护进程(daemon)是一类在后台运行的特殊进程，用于执行特定的系统任务。

很多守护进程在系统引导的时候启动，并且一直运行直到系统关闭。

守护进程一直在后台运行,脱离终端运行的程序 独立运行的守护进程

 <?php
 class myProcess
 {
     const UID = 80;
     const GID = 80;
     protected $loop = true;
     protected $pidFile = "/tmp/myprocess.pid";
     //protected $data = "123132132\r\n";

     private function checkPidFile()
     {
         if(file_exists($this->pidFile))
         {
             echo "daemon process is already runing.\n";
             exit();
         }
     }
     private function daemon()
     {

         $pid = pcntl_fork();
         if ($pid == -1)
         {
             exit("fork fail");
         }else if($pid == 0){
             $this->handler();
         }else{
             exit();
         }
     }

     private function handler()
     {
         posix_setsid();
         posix_setuid(self::UID);
         posix_setgid(self::GID);
         #fclose(STDIN);
         #fclose(STDOUT);
         #fclose(STDERR);
         #$pid = posix_getpid
         $pid = getmypid();
         file_put_contents($this->pidFile, $pid); #or die("open file fail");
     }

     private function start()
     {
         pcntl_signal_dispatch();
         $this->checkPidFile();
         $this->daemon();
         while ($this->loop) {
             $id = getmypid();
             //$f = fopen("/tmp/a.txt",a);
             //fwrite($f,$this->data);
             //file_put_contents("/tmp/".$id.".log","进程ID:$id 正常运行\r\n");
             sleep(1);
         }
     }

     private function stop()
     {
         if (file_exists($this->pidFile)) {
            $pid = file_get_contents($this->pidFile);
            posix_kill($pid, SIGHUP);
            unlink($this->pidFile);
            echo "stop success.....";
         }else{
             echo "stop fail, daemon process not is already runing";
         }
     }

     private function restart()
     {
         $this->stop();
         $this->start();
     }

     public function reload()
     {
         // $this->loop = false;
         // pcntl_signal_dispatch();
         // $this->loop = true;
         // $this->start();
     }

     public function main($argv)
     {
         switch ($argv[1]) {
              case 'start':
                $this->start();
                break;
              case 'stop':
                   $this->stop();
                   break;
             case 'restart':
                   $this->restart();
                   break;
             case 'reload':
                   $this->reload();
                   break;
              default:
                  echo 'php process.php start | stop | restart | reload';
                  exit;
         }
     }

 }

 $proce = new myProcess();
 $proce->main($argv);