PHP高级编程之守护进程，实现优雅重启
PHP高级编程之守护进程
http://netkiller.github.io/journal/php.daemon.html
Mr. Neo Chen (陈景峰), netkiller, BG7NYT
中国广东省深圳市龙华新区民治街道溪山美地
518131
+86 13113668890
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<netkiller@msn.com>php
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2014-09-01git
摘要github
2014-09-01 发表sql
2015-08-31 更新shell
2015-10-20 更新，增长优雅重启
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目录
1. 什么是守护进程
守护进程是脱离于终端而且在后台运行的进程。守护进程脱离于终端是为了不进程在执行过程当中的信息在任何终端上显示而且进程也不会被任何终端所产生的终端信息所打断。
例如 apache, nginx, mysql 都是守护进程
2. 为何开发守护进程
不少程序以服务形式存在，他没有终端或UI交互，它可能采用其余方式与其余程序交互，如TCP/UDP Socket, UNIX Socket, fifo。程序一旦启动便进入后台，直到知足条件他便开始处理任务。
3. 什么时候采用守护进程开发应用程序
以我当前的需求为例，我须要运行一个程序，而后监听某端口，持续接受服务端发起的数据，而后对数据分析处理，再将结果写入到数据库中; 我采用ZeroMQ实现数据收发。
若是我不采用守护进程方式开发该程序，程序一旦运行就会占用当前终端窗框，还有受到当前终端键盘输入影响，有可能程序误退出。
4. 守护进程的安全问题
咱们但愿程序在非超级用户运行，这样一旦因为程序出现漏洞被骇客控制，攻击者只能继承运行权限，而没法得到超级用户权限。
咱们但愿程序只能运行一个实例，不运行同事开启两个以上的程序，由于会出现端口冲突等等问题。
5. 怎样开发守护进程
例 1. 多线程守护进程例示
<?php
class ExampleWorker extends Worker {
#public function __construct(Logging $logger) {
# $this->logger = $logger;
#}
#protected $logger;
protected static $dbh;
public function __construct() {
}
public function run(){
$dbhost = '192.168.2.1'; // 数据库服务器
$dbport = 3306;
$dbuser = 'www'; // 数据库用户名
$dbpass = 'qwer123'; // 数据库密码
$dbname = 'example'; // 数据库名
self::$dbh = new PDO("mysql:host=$dbhost;port=$dbport;dbname=$dbname", $dbuser, $dbpass, array(
/* PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\'', */
PDO::MYSQL_ATTR_COMPRESS => true,
PDO::ATTR_PERSISTENT => true
)
);
}
protected function getInstance(){
return self::$dbh;
}
}
/* the collectable class implements machinery for Pool::collect */
class Fee extends Stackable {
public function __construct($msg) {
$trades = explode(",", $msg);
$this->data = $trades;
print_r($trades);
}
public function run() {
#$this->worker->logger->log("%s executing in Thread #%lu", __CLASS__, $this->worker->getThreadId() );
try {
$dbh = $this->worker->getInstance();
$insert = "INSERT INTO fee(ticket, login, volume, `status`) VALUES(:ticket, :login, :volume,'N')";
$sth = $dbh->prepare($insert);
$sth->bindValue(':ticket', $this->data[0]);
$sth->bindValue(':login', $this->data[1]);
$sth->bindValue(':volume', $this->data[2]);
$sth->execute();
$sth = null;
/* ...... */
$update = "UPDATE fee SET `status` = 'Y' WHERE ticket = :ticket and `status` = 'N'";
$sth = $dbh->prepare($update);
$sth->bindValue(':ticket', $this->data[0]);
$sth->execute();
//echo $sth->queryString;
//$dbh = null;
}
catch(PDOException $e) {
$error = sprintf("%s,%s\n", $mobile, $id );
file_put_contents("mobile_error.log", $error, FILE_APPEND);
}
}
}
class Example {
/* config */
const LISTEN = "tcp://192.168.2.15:5555";
const MAXCONN = 100;
const pidfile = __CLASS__;
const uid = 80;
const gid = 80;
protected $pool = NULL;
protected $zmq = NULL;
public function __construct() {
$this->pidfile = '/var/run/'.self::pidfile.'.pid';
}
private function daemon(){
if (file_exists($this->pidfile)) {
echo "The file $this->pidfile exists.\n";
exit();
}
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
} else if ($pid) {
// we are the parent
//pcntl_wait($status); //Protect against Zombie children
exit($pid);
} else {
// we are the child
file_put_contents($this->pidfile, getmypid());
posix_setuid(self::uid);
posix_setgid(self::gid);
return(getmypid());
}
}
private function start(){
$pid = $this->daemon();
$this->pool = new Pool(self::MAXCONN, \ExampleWorker::class, []);
$this->zmq = new ZMQSocket(new ZMQContext(), ZMQ::SOCKET_REP);
$this->zmq->bind(self::LISTEN);
/* Loop receiving and echoing back */
while ($message = $this->zmq->recv()) {
//print_r($message);
//if($trades){
$this->pool->submit(new Fee($message));
$this->zmq->send('TRUE');
//}else{
// $this->zmq->send('FALSE');
//}
}
$pool->shutdown();
}
private function stop(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
posix_kill($pid, 9);
unlink($this->pidfile);
}
}
private function help($proc){
printf("%s start | stop | help \n", $proc);
}
public function main($argv){
if(count($argv) < 2){
printf("please input help parameter\n");
exit();
}
if($argv[1] === 'stop'){
$this->stop();
}else if($argv[1] === 'start'){
$this->start();
}else{
$this->help($argv[0]);
}
}
}
$cgse = new Example();
$cgse->main($argv);
例 2. 消息队列与守护进程
<?php
declare(ticks = 1);
require_once( __DIR__.'/autoload.class.php' );
umask(077);
class EDM {
protected $queue;
public function __construct() {
global $argc, $argv;
$this->argc = $argc;
$this->argv = $argv;
$this->pidfile = $this->argv[0].".pid";
$this->config = new Config('mq');
$this->logging = new Logging(__DIR__.'/log/'.$this->argv[0].'.'.date('Y-m-d').'.log'); //.H:i:s
//print_r( $this->config->getArray('mq') );
//pcntl_signal(SIGHUP, array(&$this,"restart"));
}
protected function msgqueue(){
$exchangeName = 'email'; //交换机名
$queueName = 'email'; //队列名
$routeKey = 'email'; //路由key
//建立链接和channel
$connection = new AMQPConnection($this->config->getArray('mq'));
if (!$connection->connect()) {
die("Cannot connect to the broker!\n");
}
$this->channel = new AMQPChannel($connection);
$this->exchange = new AMQPExchange($this->channel);
$this->exchange->setName($exchangeName);
$this->exchange->setType(AMQP_EX_TYPE_DIRECT); //direct类型
$this->exchange->setFlags(AMQP_DURABLE); //持久化
$this->exchange->declare();
//echo "Exchange Status:".$this->exchange->declare()."\n";
//建立队列
$this->queue = new AMQPQueue($this->channel);
$this->queue->setName($queueName);
$this->queue->setFlags(AMQP_DURABLE); //持久化
$this->queue->declare();
//echo "Message Total:".$this->queue->declare()."\n";
//绑定交换机与队列，并指定路由键
$bind = $this->queue->bind($exchangeName, $routeKey);
//echo 'Queue Bind: '.$bind."\n";
//阻塞模式接收消息
while(true){
//$this->queue->consume('processMessage', AMQP_AUTOACK); //自动ACK应答
$this->queue->consume(function($envelope, $queue) {
$msg = $envelope->getBody();
$queue->ack($envelope->getDeliveryTag()); //手动发送ACK应答
$this->logging->info('('.'+'.')'.$msg);
//$this->logging->debug("Message Total:".$this->queue->declare());
});
$this->channel->qos(0,1);
//echo "Message Total:".$this->queue->declare()."\n";
}
$conn->disconnect();
}
protected function start(){
if (file_exists($this->pidfile)) {
printf("%s already running\n", $this->argv[0]);
exit(0);
}
$this->logging->warning("start");
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
} else if ($pid) {
//pcntl_wait($status); //等待子进程中断，防止子进程成为僵尸进程。
exit(0);
} else {
posix_setsid();
//printf("pid: %s\n", posix_getpid());
file_put_contents($this->pidfile, posix_getpid());
//posix_kill(posix_getpid(), SIGHUP);
$this->msgqueue();
}
}
protected function stop(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
posix_kill($pid, SIGTERM);
//posix_kill($pid, SIGKILL);
unlink($this->pidfile);
$this->logging->warning("stop");
}else{
printf("%s haven't running\n", $this->argv[0]);
}
}
protected function restart(){
$this->stop();
$this->start();
}
protected function status(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
printf("%s already running, pid = %s\n", $this->argv[0], $pid);
}else{
printf("%s haven't running\n", $this->argv[0]);
}
}
protected function usage(){
printf("Usage: %s {start | stop | restart | status}\n", $this->argv[0]);
}
public function main(){
//print_r($this->argv);
if($this->argc != 2){
$this->usage();
}else{
if($this->argv[1] == 'start'){
$this->start();
}else if($this->argv[1] == 'stop'){
$this->stop();
}else if($this->argv[1] == 'restart'){
$this->restart();
}else if($this->argv[1] == 'status'){
$this->status();
}else{
$this->usage();
}
}
}
}
$edm = New EDM();
$edm->main();
5.1. 程序启动
下面是程序启动后进入后台的代码
经过进程ID文件来判断，当前进程状态，若是进程ID文件存在表示程序在运行中，经过代码file_exists($this->pidfile)实现，但然后进程被kill须要手工删除该文件才能运行
private function daemon(){
if (file_exists($this->pidfile)) {
echo "The file $this->pidfile exists.\n";
exit();
}
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
} else if ($pid) {
// we are the parent
//pcntl_wait($status); //Protect against Zombie children
exit($pid);
} else {
// we are the child
file_put_contents($this->pidfile, getmypid());
posix_setuid(self::uid);
posix_setgid(self::gid);
return(getmypid());
}
}
程序启动后，父进程会推出，子进程会在后台运行，子进程权限从root切换到指定用户，同时将pid写入进程ID文件。
5.2. 程序中止
程序中止，只需读取pid文件，而后调用posix_kill($pid, 9); 最后将该文件删除。
private function stop(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
posix_kill($pid, 9);
unlink($this->pidfile);
}
}
5.3. 单例模式
全部线程共用数据库链接，在多线程中这个很是重要，若是每一个线程创建以此数据库链接在关闭，这对数据库的开销是巨大的。
protected function getInstance(){
return self::$dbh;
}
5.4. 实现优雅重启
所谓优雅重启是指进程不退出的状况加实现从新载入包含重置变量，刷新配置文件，重置日志等等
stop/start 或者 restart都会退出进程，从新启动，致使进程ID改变，同时瞬间退出致使业务闪断。因此不少守护进程都会提供一个reload功能，者就是所谓的优雅重启。
reload 实现原理是给进程发送SIGHUP信号，能够经过kill命令发送 kill -s SIGHUP 64881，也能够经过库函数实现 posix_kill(posix_getpid(), SIGUSR1);
<?php
pcntl_signal(SIGTERM, function($signo) {
echo "\n This signal is called. [$signo] \n";
Status::$state = -1;
});
pcntl_signal(SIGHUP, function($signo) {
echo "\n This signal is called. [$signo] \n";
Status::$state = 1;
Status::$ini = parse_ini_file('test.ini');
});
class Status{
public static $state = 0;
public static $ini = null;
}
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
}
if($pid) {
// parent
} else {
$loop = true;
Status::$ini = parse_ini_file('test.ini');
while($loop) {
print_r(Status::$ini);
while(true) {
// Dispatching...
pcntl_signal_dispatch();
if(Status::$state == -1) {
// Do something and end loop.
$loop = false;
break;
}
if(Status::$state == 1) {
printf("This program is reload.\r\n");
Status::$state = 0;
break;
}
echo '.';
sleep(1);
}
echo "\n";
}
echo "Finish \n";
exit();
}
建立配置文件
[root@netkiller pcntl]# cat test.ini [db] host=192.168.0.1 port=3306
测试方法，首先运行该守护进程
# php signal.reload.php Array ( [host] => 192.168.0.1 [port] => 3306 )
如今修改配置文件，增长user=test配置项
[root@netkiller pcntl]# cat test.ini [db] host=192.168.0.1 port=3306 user=test
发送信号，在另外一个终端窗口，经过ps命令找到该进程的PID，而后使用kill命令发送SIGHUP信号，而后再经过ps查看进程，你会发现进程PID没有改变
[root@netkiller pcntl]# ps ax | grep reload 64881 pts/0 S 0:00 php -c /srv/php/etc/php-cli.ini signal.reload.php 65073 pts/1 S+ 0:00 grep --color=auto reload [root@netkiller pcntl]# kill -s SIGHUP 64881 [root@netkiller pcntl]# ps ax | grep reload 64881 pts/0 S 0:00 php -c /srv/php/etc/php-cli.ini signal.reload.php 65093 pts/1 S+ 0:00 grep --color=auto reload
配置文件被从新载入
This signal is called. [1] This program is reload. Array ( [host] => 192.168.0.1 [port] => 3306 [user] => test )
优雅重启完成。
6. Example
<?php
/*
* PHP Daemon sample.
* Home: http://netkiller.github.io
* Author: netkiller<netkiller@msn.com>
*
*/
class Logger {
public function __construct(/*Logging $logger*/) {
}
public function logger($type, $message) {
$log = sprintf ( "%s\t%s\t%s\n", date ( 'Y-m-d H:i:s' ), $type, $message );
file_put_contents ( sprintf(__DIR__."/../log/sender.%s.log", date ( 'Y-m-d' )), $log, FILE_APPEND );
}
}
final class Signal{
public static $signo = 0;
protected static $ini = null;
public static function set($signo){
self::$signo = $signo;
}
public static function get(){
return(self::$signo);
}
public static function reset(){
self::$signo = 0;
}
}
class Test extends Logger {
//public static $signal = null;
public function __construct() {
//self::$signal == null;
}
public function run(){
while(true){
pcntl_signal_dispatch();
printf(".");
sleep(1);
if(Signal::get() == SIGHUP){
Signal::reset();
break;
}
}
printf("\n");
}
}
class Daemon extends Logger {
/* config */
const LISTEN = "tcp://192.168.2.15:5555";
const pidfile = __CLASS__;
const uid = 80;
const gid = 80;
const sleep = 5;
protected $pool = NULL;
protected $config = array();
public function __construct($uid, $gid, $class) {
$this->pidfile = '/var/run/'.basename(get_class($class), '.php').'.pid';
//$this->config = parse_ini_file('sender.ini', true); //include_once(__DIR__."/config.php");
$this->uid = $uid;
$this->gid = $gid;
$this->class = $class;
$this->classname = get_class($class);
$this->signal();
}
public function signal(){
pcntl_signal(SIGHUP, function($signo) /*use ()*/{
//echo "\n This signal is called. [$signo] \n";
printf("The process has been reload.\n");
Signal::set($signo);
});
}
private function daemon(){
if (file_exists($this->pidfile)) {
echo "The file $this->pidfile exists.\n";
exit();
}
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
} else if ($pid) {
// we are the parent
//pcntl_wait($status); //Protect against Zombie children
exit($pid);
} else {
file_put_contents($this->pidfile, getmypid());
posix_setuid(self::uid);
posix_setgid(self::gid);
return(getmypid());
}
}
private function run(){
while(true){
printf("The process begin.\n");
$this->class->run();
printf("The process end.\n");
}
}
private function foreground(){
$this->run();
}
private function start(){
$pid = $this->daemon();
for(;;){
$this->run();
sleep(self::sleep);
}
}
private function stop(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
posix_kill($pid, 9);
unlink($this->pidfile);
}
}
private function reload(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
//posix_kill(posix_getpid(), SIGHUP);
posix_kill($pid, SIGHUP);
}
}
private function status(){
if (file_exists($this->pidfile)) {
$pid = file_get_contents($this->pidfile);
system(sprintf("ps ax | grep %s | grep -v grep", $pid));
}
}
private function help($proc){
printf("%s start | stop | restart | status | foreground | help \n", $proc);
}
public function main($argv){
if(count($argv) < 2){
$this->help($argv[0]);
printf("please input help parameter\n");
exit();
}
if($argv[1] === 'stop'){
$this->stop();
}else if($argv[1] === 'start'){
$this->start();
}else if($argv[1] === 'restart'){
$this->stop();
$this->start();
}else if($argv[1] === 'status'){
$this->status();
}else if($argv[1] === 'foreground'){
$this->foreground();
}else if($argv[1] === 'reload'){
$this->reload();
}else{
$this->help($argv[0]);
}
}
}
$daemon = new Daemon(80,80, new Test());
$daemon->main($argv);
?>
7. 进程意外退出解决方案
若是是很是重要的进程，必需要保证程序正常运行，一旦出现任何异常退出，都须要作即时作处理。下面的程序可能检查进程是否异常退出，若是退出便当即启动。
#!/bin/sh
LOGFILE=/var/log/$(basename $0 .sh).log
PATTERN="my.php"
RECOVERY="/path/to/my.php start"
while true
do
TIMEPOINT=$(date -d "today" +"%Y-%m-%d_%H:%M:%S")
PROC=$(pgrep -o -f ${PATTERN})
#echo ${PROC}
if [ -z "${PROC}" ]; then
${RECOVERY} >> $LOGFILE
echo "[${TIMEPOINT}] ${PATTERN} ${RECOVERY}" >> $LOGFILE
#else
#echo "[${TIMEPOINT}] ${PATTERN} ${PROC}" >> $LOGFILE
fi
sleep 5
done &
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