怎么用PHP写守护进程类

本篇内容主要讲解"怎么用PHP写守护进程类"，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习"怎么用PHP写守护进程类"吧!

用PHP实现的Daemon类。可以在服务器上实现队列或者脱离 crontab 的计划任务。
使用的时候，继承于这个类，并重写 _doTask 方法，通过 main 初始化执行。

_logMessage('Starting daemon');     if (!$this->_daemonize()) {      $this->_logMessage('Could not start daemon', self::DLOG_ERROR);       return false;    }     $this->_logMessage('Running...');     $this->_isRunning = true;     while ($this->_isRunning) {      $this->_doTask();    }     return true;  }   /**   * 停止进程   *   * @return void   */  public function stop() {     $this->_logMessage('Stoping daemon');     $this->_isRunning = false;  }   /**   * Do task   *   * @return void   */  protected function _doTask() {    // override this method  }   /**   * _logMessage   * 记录日志   *   * @param string 消息   * @param integer 级别   * @return void   */  protected function _logMessage($msg, $level = self::DLOG_NOTICE) {    // override this method  }   /**   * Daemonize   *   * Several rules or characteristics that most daemons possess:   * 1) Check is daemon already running   * 2) Fork child process   * 3) Sets identity   * 4) Make current process a session laeder   * 5) Write process ID to file   * 6) Change home path   * 7) umask(0)   *   * @access private   * @since 1.0   * @return void   */  private function _daemonize() {     ob_end_flush();     if ($this->_isDaemonRunning()) {      // Deamon is already running. Exiting      return false;    }     if (!$this->_fork()) {      // Coudn't fork. Exiting.      return false;    }     if (!$this->_setIdentity() && $this->requireSetIdentity) {      // Required identity set failed. Exiting      return false;    }     if (!posix_setsid()) {      $this->_logMessage('Could not make the current process a session leader', self::DLOG_ERROR);       return false;    }     if (!$fp = fopen($this->pidFileLocation, 'w')) {      $this->_logMessage('Could not write to PID file', self::DLOG_ERROR);      return false;    } else {      fputs($fp, $this->_pid);      fclose($fp);    }     // 写入监控日志    $this->writeProcess();     chdir($this->homePath);    umask(0);     declare(ticks = 1);     pcntl_signal(SIGCHLD, array(&$this, 'sigHandler'));    pcntl_signal(SIGTERM, array(&$this, 'sigHandler'));    pcntl_signal(SIGUSR1, array(&$this, 'sigHandler'));    pcntl_signal(SIGUSR2, array(&$this, 'sigHandler'));     return true;  }   /**   * Cheks is daemon already running   *   * @return bool   */  private function _isDaemonRunning() {     $oldPid = file_get_contents($this->pidFileLocation);     if ($oldPid !== false && posix_kill(trim($oldPid),0))    {      $this->_logMessage('Daemon already running with PID: '.$oldPid, (self::DLOG_TO_CONSOLE | self::DLOG_ERROR));       return true;    }    else    {      return false;    }  }   /**   * Forks process   *   * @return bool   */  private function _fork() {     $this->_logMessage('Forking...');     $pid = pcntl_fork();     if ($pid == -1) {      // 出错      $this->_logMessage('Could not fork', self::DLOG_ERROR);       return false;    } elseif ($pid) {      // 父进程      $this->_logMessage('Killing parent');       exit();    } else {      // fork的子进程      $this->_isChildren = true;      $this->_pid = posix_getpid();       return true;    }  }   /**   * Sets identity of a daemon and returns result   *   * @return bool   */  private function _setIdentity() {     if (!posix_setgid($this->groupID) || !posix_setuid($this->userID))    {      $this->_logMessage('Could not set identity', self::DLOG_WARNING);       return false;    }    else    {      return true;    }  }   /**   * Signals handler   *   * @access public   * @since 1.0   * @return void   */  public function sigHandler($sigNo) {     switch ($sigNo)    {      case SIGTERM:  // Shutdown        $this->_logMessage('Shutdown signal');        exit();        break;       case SIGCHLD:  // Halt        $this->_logMessage('Halt signal');        while (pcntl_waitpid(-1, $status, WNOHANG) > 0);        break;      case SIGUSR1:  // User-defined        $this->_logMessage('User-defined signal 1');        $this->_sigHandlerUser1();        break;      case SIGUSR2:  // User-defined        $this->_logMessage('User-defined signal 2');        $this->_sigHandlerUser2();        break;    }  }   /**   * Signals handler: USR1   * 主要用于定时清理每个进程里被缓存的域名dns解析记录   *   * @return void   */  protected function _sigHandlerUser1() {    apc_clear_cache('user');  }   /**   * Signals handler: USR2   * 用于写入心跳包文件   *   * @return void   */  protected function _sigHandlerUser2() {     $this->_initProcessLocation();     file_put_contents($this->processHeartLocation, time());     return true;  }   /**   * Releases daemon pid file   * This method is called on exit (destructor like)   *   * @return void   */  public function releaseDaemon() {     if ($this->_isChildren && is_file($this->pidFileLocation)) {      $this->_logMessage('Releasing daemon');       unlink($this->pidFileLocation);    }  }   /**   * writeProcess   * 将当前进程信息写入监控日志，另外的脚本会扫描监控日志的数据发送信号，如果没有响应则重启进程   *   * @return void   */  public function writeProcess() {     // 初始化 proc    $this->_initProcessLocation();     $command = trim(implode(' ', $_SERVER['argv']));     // 指定进程的目录    $processDir = $this->processLocation . '/' . $this->_pid;    $processCmdFile = $processDir . '/cmd';    $processPwdFile = $processDir . '/pwd';     // 所有进程所在的目录    if (!is_dir($this->processLocation)) {      mkdir($this->processLocation, 0777);      chmod($processDir, 0777);    }     // 查询重复的进程记录    $pDirObject = dir($this->processLocation);    while ($pDirObject && (($pid = $pDirObject->read()) !== false)) {      if ($pid == '.' || $pid == '..' || intval($pid) != $pid) {        continue;      }       $pDir = $this->processLocation . '/' . $pid;      $pCmdFile = $pDir . '/cmd';      $pPwdFile = $pDir . '/pwd';      $pHeartFile = $pDir . '/heart';       // 根据cmd检查启动相同参数的进程      if (is_file($pCmdFile) && trim(file_get_contents($pCmdFile)) == $command) {        unlink($pCmdFile);        unlink($pPwdFile);        unlink($pHeartFile);         // 删目录有缓存        usleep(1000);         rmdir($pDir);      }    }     // 新进程目录    if (!is_dir($processDir)) {      mkdir($processDir, 0777);      chmod($processDir, 0777);    }     // 写入命令参数    file_put_contents($processCmdFile, $command);    file_put_contents($processPwdFile, $_SERVER['PWD']);     // 写文件有缓存    usleep(1000);     return true;  }   /**   * _initProcessLocation   * 初始化   *   * @return void   */  protected function _initProcessLocation() {     $this->processLocation = ROOT_PATH . '/app/data/proc';    $this->processHeartLocation = $this->processLocation . '/' . $this->_pid . '/heart';  }}

到此，相信大家对"怎么用PHP写守护进程类"有了更深的了解，不妨来实际操作一番吧！这里是网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！