php守护进程

<?phpclass 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 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';    }}