关于消息队列——ZeroMQ的router/dealer
为了不将服务端直接暴露给“客户端”,增加可扩展性,我们可以制作个中间层broker(参照官方示例代码)
比如request-reply这种最简单的模型,我们可以通过一个中间组件将后面的服务透明化,增强系统的可扩展性,后台只需要增加service数目就可以增强服务能力
架构模型如下:
1,服务端worker.php
(不用bind端口,只需要"监听"中间件broker的套接口即可)
<?php
/*
* Hello World server
* Connects REP socket to tcp://*:5560
* Expects "Hello" from client, replies with "World"
* @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
*/
$context = new ZMQContext();
// Socket to talk to clients
$responder = new ZMQSocket($context, ZMQ::SOCKET_REP);
$responder->connect("tcp://localhost:5560");
while (true) {
// Wait for next request from client
$string = $responder->recv();
printf ("Received request: [%s]%s", $string, PHP_EOL);
// Do some 'work'
sleep(1);
// Send reply back to client
$responder->send("World");
}
?>
2,客户端client.php
<?php
/*
* Hello World client
* Connects REQ socket to tcp://localhost:5559
* Sends "Hello" to server, expects "World" back
* @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
*/
$context = new ZMQContext();
// Socket to talk to server
$requester = new ZMQSocket($context, ZMQ::SOCKET_REQ);
$requester->connect("tcp://localhost:5559");
for ($request_nbr = 0; $request_nbr < 10; $request_nbr++) {
$requester->send("Hello");
$string = $requester->recv();
printf ("Received reply %d [%s]%s", $request_nbr, $string, PHP_EOL);
}
?>
3,中间件broker.php
不处理任务,只是转发消息,通过poll实现异步IO(连接客户端client的不能再是REP而应该是ROUTER,同理连接服务端worker的不能是REQ而应该是DEALER)
<?php
/*
* Simple request-reply broker
* @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
*/
// Prepare our context and sockets
$context = new ZMQContext();
$frontend = new ZMQSocket($context, ZMQ::SOCKET_ROUTER);
$backend = new ZMQSocket($context, ZMQ::SOCKET_DEALER);
$frontend->bind("tcp://*:5559");
$backend->bind("tcp://*:5560");
// Initialize poll set
$poll = new ZMQPoll();
$poll->add($frontend, ZMQ::POLL_IN);
$poll->add($backend, ZMQ::POLL_IN);
$readable = $writeable = array();
// Switch messages between sockets
while (true) {
$events = $poll->poll($readable, $writeable);
foreach ($readable as $socket) {
if ($socket === $frontend) {
// Process all parts of the message
while (true) {
$message = $socket->recv();
// Multipart detection
$more = $socket->getSockOpt(ZMQ::SOCKOPT_RCVMORE);
$backend->send($message, $more ? ZMQ::MODE_SNDMORE : null);
if (!$more) {
break; // Last message part
}
}
} elseif ($socket === $backend) {
$message = $socket->recv();
// Multipart detection
$more = $socket->getSockOpt(ZMQ::SOCKOPT_RCVMORE);
$frontend->send($message, $more ? ZMQ::MODE_SNDMORE : null);
if (!$more) {
break; // Last message part
}
}
}
}
?>
运行broker.php以及多个worker.php,然后运行client.php(也可以是多个),可以看到10个任务被分担给多个worker.php运行了。
这样就很简单的实现一个n:m的通信了
根据这个模型我们还可以定制一个支持负载均衡的broker,详细代码可以参照
https://github.com/imatix/zguide/blob/master/examples/PHP/lbbroker.php