分享PHP守护进程类

<?php
 
class Daemon {
 
  const DLOG_TO_CONSOLE = 1;
  const DLOG_NOTICE = 2;
  const DLOG_WARNING = 4;
  const DLOG_ERROR = 8;
  const DLOG_CRITICAL = 16;
 
  const DAPC_PATH = '/tmp/daemon_apc_keys';
 
  /
    User ID
   
    @var int
   /
  public $userID = 65534; // nobody
 
  /
    Group ID
   
    @var integer
   /
  public $groupID = 65533; // nobody
 
  /
    Terminate daemon when set identity failure ?
   
    @var bool
    @since 1.0.3
   /
  public $requireSetIdentity = false;
 
  /
    Path to PID file
   
    @var string
    @since 1.0.1
   /
  public $pidFileLocation = '/tmp/daemon.pid';
 
  /
    processLocation
    进程信息记录目录
   
    @var string
   /
  public $processLocation = '';
 
  /
    processHeartLocation
    进程心跳包文件
   
    @var string
   /
  public $processHeartLocation = '';
 
  /
    Home path
   
    @var string
    @since 1.0
   /
  public $homePath = '/';
 
  /
    Current process ID
   
    @var int
    @since 1.0
   /
  protected $_pid = 0;
 
  /
    Is this process a children
   
    @var boolean
    @since 1.0
   /
  protected $_isChildren = false;
 
  /
    Is daemon running
   
    @var boolean
    @since 1.0
   /
  protected $_isRunning = false;
 
  /
    Constructor
   
    @return void
   /
  public function __construct() {
 
    error_reporting(0);
    set_time_limit(0);
    ob_implicit_flush();
 
    register_shutdown_function(array(&$this, 'releaseDaemon'));
  }
 
  /
    启动进程
   
    @return bool
   /
  public function main() {
 
    $this->_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 s() {
 
    $this->_logMessage('Sing 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)
   
    @aess 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);
 
    ptl_signal(SIGCHLD, array(&$this, 'sigHandler'));
    ptl_signal(SIGTERM, array(&$this, 'sigHandler'));
    ptl_signal(SIGUSR1, array(&$this, 'sigHandler'));
    ptl_signal(SIGUSR2, array(&$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 = ptl_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
   
    @aess 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 (ptl_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，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();
 
    $mand = 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)) == $mand) {
        unlink($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, $mand);
    file_put_contents($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';
  }
}