KalonDaemon - 守护进程PHP版

声明：这篇文章是我09年的时候发表在自己之前的BLOG上的，属于原创内容，现在将文章转移到这里。

守护进程也称精灵进程(daemon)，是生存期较长的一种进程。它们常常用在系统自举时启动，仅在系统关闭时才终止。因为它们没有控制终端，所以说它们是在后台运行的。UNIX类操作系统有很多的守护进程，它们执行日常事务活动。

目前有大量的web站点基与PHP开发，业务逻辑都是由PHP来实现，很多时候我们也需要一个PHP的daemon来做一些日常事务，例如我们想每隔一个小时统计一下数据库中的某项数据，每天定期的执行一些备份或则监控任务。这些任务在apache模块的web环境下实现比较困难而且容易引发很多问题。
这里我介绍一款我自己写的PHP5版的daemon类 - KalonDaemon.   ^_^  现在和大家一起分享。

概要：
    KalonDaemon是一款PHP5的daemon类，我们在PHP代码中可以直接包含并且使用，KalonDaemon工作在cli sapi下（ command line interface）,它能把一个普通的PHP进程变成一个守护进程。
使用方式：
  在PHP脚本中包含了KalonDaemon设置好参数然后调用start()方法。然后我们在命令行下用PHP cli执行脚本，比如cli sapi路径为 /usr/local/bin/php,   我们编写的程序路径 /home/test/mydaemon.php,那么我们用以下方式运行程序：          /usr/local/bin/php  /home/test/mydaemon.php   根据需要可以在后面添加别的参数。
工作流程：
KalonDaemon遵循大部分unix类系统下的守护进程编程规则，主要工作流程如下：
1. 调用pcntl_fork，然后使父进程退出（exit）.这样做实现如下几点：第一，如果该守护进程是作为一条shell命令启动，那么父进程终止使得 shell认为这条命令已经执行完毕；第二，子进程继承父进程的进程组ID，但是具有一个新的进程ID，这就保证了子进程不是一个进程组的组长，这对于下面要做的posix_setsid调用是必要的前提条件。
2.调用posix_setsid以创建一个新的会话，这样新进程就成为了新会话的首进程，同时是新进程组的组长进程，而且没有控制终端。
3.设置进程信号回调函数，方便我们用其它进程对守护进程进行控制。

 

以下是mydaemon.php的源码：

 

<?phprequire_once './KalonDaemon.php';declare(ticks = 1);$toDo = $_SERVER['argv'][1];$daemonConf = array('pidFileName' => 'mydaemon.pid', 'verbose' => true);function myHandler1(){ sleep(5); echo "This handler1 works./n";}function myHandler2(){ echo "This handler2 works./n";}try { $daemon = new KalonDaemon($daemonConf); if ($toDo == 'start') { $daemon->addSignalHandler(SIGUSR1, 'myHandler1'); $daemon->addSignalHandler(SIGUSR2, 'myHandler2'); $daemon->start(); for (;;) { echo "running./n"; sleep(1000); } } elseif ($toDo == 'stop') { $daemon->stop(); } else { die("unknown action."); }} catch (KalonDaemonException $e) { echo $e->getMessage(); echo "/n";}?>

 

在命令行下执行：

/path/to/phpcli/php  mydaemon.php start

 

输出如下信息：

Daemon started with pid 8976...
running.

说明守护进程已经开始运行，进程号为8976，当然一般情况进程号每次都会不一样。

 

由于mydaemon.php中有一个死循环，每次循环会睡眠1000秒，所以进程永远不会终止。

mydaemon.php中为守护进程注册了两个信号句柄，信号SIGUSR1对应函数myHandler1(), 信号SIGUSR2对应myHandler2()，我们可以通过kill命令给进程发送这两个信号来唤醒进程。

 

kill -SIGUSR2 8976

输出信息如下：

This handler2 works.
running.

说明睡眠中的进程被唤醒，并且执行了myHandler2()函数，然后再次进入了循环。

 

 

当我们需要终止守护进程的时候，可以用以下命令：

/path/to/phpcli/php  mydaemon.php stop

输出信息如下：

Daemon stopped with pid 8976...

这样守护进程就终止了。

 

这样的特性可以在某些应用场景非常有用，比如服务器在接受到一些上传的数据之后，需要唤醒守护进程来处理这些数据。守护进程可以长期出去睡眠状态等待，当数据到来之后，发送信号唤醒守护进程，守护进程马上开始处理这些数据。这样要比定期的轮询效率高很多，而且不会有延迟现象。

 

 

KalonDaemon.php

<?php/** * Kalon Daemon -> A Unix Daemon for PHP5 * This is a free daemon tool, you can use it anyway you like. * * NOTICE: * 1:This tool must run in cli sapi, any other sapis will cause a * KalonDaemonException thrown.so you need to use this tool in a * command line interface,command such as: /path/to/php mydaemon.php * * 2:Daemon needs pcntl and posix extension support. Make sure your cli * sapi has loaded these two extension.The posix is compiled in php by * default, while pcntl must be compiled or dynamic load by yourself. * Missing anyone of these extension will cause a KalonDaemonException * thrown. * * USAGE: * *put the code below in mydaemon.php * require_once '/path/to/KalonDaemon.php';declare(ticks = 1);$toDo = $_SERVER['argv'][1];$daemonConf = array('pidFileName' => 'mydaemon.pid', 'verbose' => true);function myHandler1(){ sleep(5); echo "This handler1 works./n";}function myHandler2(){ echo "This handler2 works./n";}try { $daemon = new KalonDaemon($daemonConf); if ($toDo == 'start') { $daemon->addSignalHandler(SIGUSR1, 'myHandler1'); $daemon->addSignalHandler(SIGUSR2, 'myHandler2'); $daemon->start(); for (;;) { echo "running./n"; sleep(1000); } } elseif ($toDo == 'stop') { $daemon->stop(); } else { die("unknown action."); }} catch (KalonDaemonException $e) { echo $e->getMessage(); echo "/n";} * * then open a command shell: * start daemon: * /path/to/phpcli/php /path/to/mydaemon.php start * * stop daemon: * /path/to/phpcli/php /path/to/mydaemon.php stop * * * * @author 玉面修罗 - Kalon * @version 1.0 * @site: http://blog.csdn.net/phpkernel * E-mail/MSN: [e-mail] */class KalonDaemon {/** * path of pid file * * @var string */private $_pidFilePath = "/var/run";/** * name of pid file * * @var string */private $_pidFileName = "daemon.pid";/** * out put run information * * @var boolean */private $_verbose = false;/** * default singleton model * * @var boolean */private $_singleton = true; /** * close file handle STDIN STDOUT STDERR * NOTICE: we do not close STDIN STDOUT STDERR indeed for some reason. * @var boolean */private $_closeStdHandle = true;/** * pid of daemon * * @var int */private $_pid = 0;/** * exec file * * @var string */private $_execFile = "";/** * function handlers for signal number * * @var array */ private $_signalHandlerFuns = array();/** * set config * * @param array $configs */public function __construct($configs = array()){ //load config if (is_array($configs)) $this->setConfigs($configs);}/** * pctntl is needed,and only works in cli sapi */ public function _checkRequirement() { //check if pctnl loaded if (!extension_loaded('pcntl')) throw new KalonDaemonException("daemon needs support of pcntl extension, please enable it."); //check sapi name,only for cli if ('cli' != php_sapi_name()) throw new KalonDaemonException("daemon only works in cli sapi."); } /** * set configs * pidFilePath: path of pid file * pidFileName: name of pid file * verbose : output process information * singleton : singleton model,only one instance of daemon at one time * closeStdHandle : close STDIN STDOUT STDERR when daemon run success * * @param array $configs */public function setConfigs($configs){ foreach ((array) $configs as $item => $config) { switch ($item) { case "pidFilePath": $this->setPidFilePath($config); break; case "pidFileName": $this->setPidFileName($config); break; case "verbose": $this->setVerbose($config); break; case "singleton": $this->setSingleton($config); break; case "closeStdHandle"; $this->setCloseStdHandle($config); break; default: throw new KalonDaemonException("Unknown config item {$item}"); break; } }}/** * set Pid File Path * * @param string $path * @return boolean */public function setPidFilePath($path){ if (empty($path)) return false; if(!is_dir($path)) if (!mkdir($path, 0777)) throw new KalonDaemonException("setPidFilePath: cannnot make dir {$path}."); $this->_pidFilePath = rtrim($path, "/"); return true; }/** * get Pid File Path * * @return string */public function getPidFilePath(){ return $this->_pidFilePath;}/** * set Pid File Name * * @param string $name * @return boolean */public function setPidFileName($name){ if (empty($name)) return false; $this->_pidFileName = trim($name); return true; }/** * get Pid File Name * * @return string */public function getPidFileName(){ return $this->_pidFileName;}/** * set Open Output * if sets to true,daemon will output start and stop information ,etc * * @param boolean $open * @return boolean */public function setVerbose($open = true){ $this->_verbose = (boolean) $open; return true;}/** * get Open Output * * @return boolean */public function getVerbose(){ return $this->_verbose;}/** * set Singleton * if sets to true, daemon will keep singleton,which means that there is only one * instance of daemon at one time. * * @param boolean $singleton * @return boolean */public function setSingleton($singleton = true){ $this->_singleton = (boolean) $singleton; return true;}/** * get Singleton * * @return boolean */public function getSingleton(){ return $this->_singleton;}/** * set Close Std Handle * * @param boolean $close * @return boolean */public function setCloseStdHandle($close = true){ $this->_closeStdHandle = (boolean) $close; return true;}/** * get Close Std Handle * * @return boolean */public function getCloseStdHandle(){ return $this->_closeStdHandle;}/** * start daemon * 1.daemonize * 2.setup signal handlers * 3.close STDIN STDOUT STDERR * * @return boolean */public function start(){ //this line used to put in the __construct,for some reason I move it here. $this->_checkRequirement(); //do daemon$this->_daemonize(); //default handler for stop if(!pcntl_signal(SIGTERM, array($this,"signalHandler"))) throw new KalonDaemonException("Cannot setup signal handler for signo {$signo}"); //close file handle STDIN STDOUT STDERR //notic!!!This makes no use in PHP4 and some early version of PHP5 //if we close these handle without dup to /dev/null,php process will die //when operating on them. if ($this->_closeStdHandle) { //fclose(STDIN); //fclose(STDOUT); //fclose(STDERR); } return true;}/** * stop daemon * 1.get daemon pid from pid file * 2.send signal to daemon * * @param boolean $force kill -9 or kill * @return boolean */public function stop($force = false){ if ($force) $signo = SIGKILL; //kill -9 else $signo = SIGTERM; //kill //only use in singleton model if (!$this->_singleton) throw new KalonDaemonException("'stop' only use in singleton model."); if (false === ($pid = $this->_getPidFromFile())) throw new KalonDaemonException("daemon is not running,cannot stop.");if (!posix_kill($pid, $signo)) { throw new KalonDaemonException("Cannot send signal $signo to daemon.");}$this->_unlinkPidFile();$this->_out("Daemon stopped with pid {$pid}...");return true;}/** * restart daemon */public function restart(){$this->stop();//sleep to waitsleep(1);$this->start();}/** * get daemon pid * @return int */public function getDaemonPid(){return $this->_getPidFromFile();}/** * signalHander for dameon * * @param int $signo */public function signalHandler($signo){$signFuns = $this->_signalHandlerFuns[$signo];if (is_array($signFuns)) { foreach ($signFuns as $fun) { call_user_func($fun); }}//default actionswitch ($signo) {case SIGTERM:exit;break;default:// handle all other signals}}public function addSignalHandler($signo, $fun){ if (is_string($fun)) { if (!function_exists($fun)) { throw new KalonDaemonException("handler function {$fun} not exists"); } }elseif (is_array($fun)) { if (!@method_exists($fun[0], $fun[1])) { throw new KalonDaemonException("handler method not exists"); } } else { throw new KalonDaemonException("error handler."); } if(!pcntl_signal($signo, array($this,"signalHandler"))) throw new KalonDaemonException("Cannot setup signal handler for signo {$signo}"); $this->_signalHandlerFuns[$signo][] = $fun; return $this; }public function sendSignal($signo){if (false === ($pid = $this->_getPidFromFile())) throw new KalonDaemonException("daemon is not running,cannot send signal.");if (!posix_kill($pid, $signo)) { throw new KalonDaemonException("Cannot send signal $signo to daemon.");}//$this->_out("Send signal $signo to pid $pid...");return true;}/** * daemon is active? * @return boolean */public function isActive(){try {$pid = $this->_getPidFromFile();} catch (KalonDaemonException $e) {return false;}if (false === $pid) return false; if (false === ($active = @pcntl_getpriority($pid))) return false; else return true;}/** * daemonize * 1.check running , if singaleton model * 2.forck process * 3.detach from controlling terminal * 4.log pid * * @return boolean */private function _daemonize(){//single model, first check if runningif ($this->_singleton) { $isRunning = $this->_checkRunning(); if ($isRunning) throw new KalonDaemonException("Daemon already running");}//fork current process$pid = pcntl_fork();if ($pid == -1) {//fork errorthrow new KalonDaemonException("Error happened while fork process");} elseif ($pid) {//parent exitexit();} else {//child, get pid$this->_pid = posix_getpid();}$this->_out("Daemon started with pid {$this->_pid}...");//detach from controlling terminalif (!posix_setsid())throw new KalonDaemonException("Cannot detach from terminal"); //log pid in singleton modelif ($this->_singleton) $this->_logPid();return $this->_pid;}/** * get Pid From File * * @return int */private function _getPidFromFile(){ //if is set if ($this->_pid) return (int)$this->_pid; $pidFile = $this->_pidFilePath . "/" . $this->_pidFileName;//no pid file,it's the first time of runningif (!file_exists($pidFile)) return false; if (!$handle = fopen($pidFile, "r")) throw new KalonDaemonException("Cannot open pid file {$pidFile} for read"); if (($pid = fread($handle, 1024)) === false) throw new KalonDaemonException("Cannot read from pid file {$pidFile}"); fclose($handle);return $this->_pid = (int) $pid;}/** * _checkRunning * in singleton mode ,we check if daemon running * * @return boolean */private function _checkRunning(){$pid = $this->_getPidFromFile();//no pid file,not runningif(false === $pid) return false;//get exe file path from pid switch(strtolower(PHP_OS)){case "freebsd":$strExe = $this->_getFreebsdProcExe($pid);if($strExe === false)return false;$strArgs = $this->_getFreebsdProcArgs($pid);break;case "linux":$strExe = $this->_getLinuxProcExe($pid);if($strExe === false)return false;$strArgs = $this->_getLinuxProcArgs($pid);break;default:return false;}$exeRealPath = $this->_getDaemonRealPath($strArgs, $pid);//get exe file path from commandif ($strExe != PHP_BINDIR . "/php") return false; $selfFile = ""; $sapi = php_sapi_name();switch($sapi){case "cgi":case "cgi-fcgi":$selfFile = $_SERVER['argv'][0];break;default:$selfFile = $_SERVER['PHP_SELF'];break;}$currentRealPath = realpath($selfFile);//compare two pathif ($currentRealPath != $exeRealPath) return false; else return true;}/** * log Pid */private function _logPid(){$pidFile = $this->_pidFilePath . "/" . $this->_pidFileName;if (!$handle = fopen($pidFile, "w")) {throw new KalonDaemonException("Cannot open pid file {$pidFile} for write"); }if (fwrite($handle, $this->_pid) == false) {throw new KalonDaemonException("Cannot write to pid file {$pidFile}"); }fclose($handle);}/** * unlink pid file * in singleton mode, unlink pid file while daemon stop * * @return boolean */ private function _unlinkPidFile() { $pidFile = $this->_pidFilePath . '/' . $this->_pidFileName; return @unlink($pidFile); }/** * get Daemon RealPath * * @param string $daemonFile * @param int $daemonPid * @return string */private function _getDaemonRealPath($daemonFile, $daemonPid){$daemonFile = trim($daemonFile);if(substr($daemonFile,0,1) !== "/") {$cwd = $this->_getLinuxProcCwd($daemonPid);$cwd = rtrim($cwd, "/");$cwd = $cwd . "/" . $daemonFile;$cwd = realpath($cwd);return $cwd;}return realpath($daemonFile);}/** * get Freebsd ProcExe * * @param int $pid * @return string */private function _getFreebsdProcExe($pid){$strProcExeFile = "/proc/" . $pid . "/file";if (false === ($strLink = @readlink($strProcExeFile))) { //throw new KalonDaemonException("Cannot read link file {$strProcExeFile}"); return false;} return $strLink;}/** * get Linux Proc Exe * * @param int $pid * @return string */private function _getLinuxProcExe($pid){$strProcExeFile = "/proc/" . $pid . "/exe";if (false === ($strLink = @readlink($strProcExeFile))) { //throw new KalonDaemonException("Cannot read link file {$strProcExeFile}"); return false; } return $strLink;}/** * get Freebsd Proc Args * * @param int $pid * @return string */private function _getFreebsdProcArgs($pid){return $this->_getLinuxProcArgs($pid);}/** * get Linux Proc Args * * @param int $pid * @return string */private function _getLinuxProcArgs($pid){$strProcCmdlineFile = "/proc/" . $pid . "/cmdline";if (!$fp = @fopen($strProcCmdlineFile, "r")) { throw new KalonDaemonException("Cannot open file {$strProcCmdlineFile} for read"); }if (!$strContents = fread($fp, 4096)) { throw new KalonDaemonException("Cannot read or empty file {$strProcCmdlineFile}"); }fclose($fp);$strContents = preg_replace("/[^/w/.///-]/", " ", trim($strContents));$strContents = preg_replace("//s+/", " ", $strContents);$arrTemp = explode(" ", $strContents);if(count($arrTemp) < 2) { throw new KalonDaemonException("Invalid content in {$strProcCmdlineFile}"); }return trim($arrTemp[1]);}/** * get Linux Proc Cwd * * @param int $pid * @return string */private function _getLinuxProcCwd($pid){$strProcExeFile = "/proc/" . $pid . "/cwd";if (false === ($strLink = @readlink($strProcExeFile))) { throw new KalonDaemonException("Cannot read link file {$strProcExeFile}"); }return $strLink;}/** * out put process info * if open _openOutput * * @param string $str * @return boolean */private function _out($str){ if ($this->_verbose) { fwrite(STDOUT, $str . "/n"); } return true; }}/** * Exception for KalonDaemon */class KalonDaemonException extends Exception { }?>