转载

swoole教程第一节:进程管理模块(Process)-中(消息队列)

不多说，上代码

<?php $workers = []; $worker_num = 2; for($i = 0; $i < $worker_num; $i++) {  $process = new swoole_process('callback_function', false, false);  $process->useQueue();  $pid = $process->start();  $workers[$pid] = $process;  //echo "Master: new worker, PID=".$pid."/n"; } function callback_function(swoole_process $worker) {  //echo "Worker: start. PID=".$worker->pid."/n";  //recv data from master  $recv = $worker->pop();  echo "From Master: $recv/n";  sleep(2);  $worker->exit(0); } foreach($workers as $pid => $process) {  $process->push("hello worker[$pid]/n"); } for($i = 0; $i < $worker_num; $i++) {  $ret = swoole_process::wait();  $pid = $ret['pid'];  unset($workers[$pid]);  echo "Worker Exit, PID=".$pid.PHP_EOL; }

这段代码出自消息队列

我想说五个点

swoole_process 的创建默认是创建的管道，当想用消息队列时，记得 把参数设成false (其实我发现不写也行)
useQueue要在start的之前调用，
pop方法 默认是阻塞的
一定一定要写wait (这里坑死不少人)

还有第五点注意事项，我接下来重点说，因为这个点卡了我好久。

嘛，demo里面只是说主进程向子进程发数据，没有子进程向主进程发数据，我就来加上吧

<?php $workers = []; $worker_num = 2; for($i = 0; $i < $worker_num; $i++) {  $process = new swoole_process('callback_function',false,false);  $process->useQueue();  $pid = $process->start();  $workers[$pid] = $process;  //echo "Master: new worker, PID=".$pid."/n"; } function callback_function(swoole_process $worker) {  //echo "Worker: start. PID=".$worker->pid."/n";  //recv data from master  $recv = $worker->pop();  echo "From Master: $recv/n";  $worker->push(" /n   hehe   /n ");//这里子进程向主进程发送  hehe  sleep(2);//注意这里有个sleep  $worker->exit(0); } foreach($workers as $pid => $process) {  $process->push("hello worker[$pid]/n");  $result = $process->pop();  echo "From worker: $result/n";//这里主进程，接受到的子进程的数据 } for($i = 0; $i < $worker_num; $i++) {  $ret = swoole_process::wait();  $pid = $ret['pid'];  unset($workers[$pid]);  echo "Worker Exit, PID=".$pid.PHP_EOL; }

运行结果完美，我就不贴了，

我看着代码，忽然发现自己没把sleep删掉，然后 噩梦开始 了

大家把上面代码的sleep注释后运行看看，我这里贴上我的运行结果

From Master: hello worker[3667] From worker:    hehe  PHP Warning:  swoole_process::push(): msgsnd() failed. Error: Invalid argument[22] in /home/sun/learn/swoole/process/demo.php on line 28 PHP Warning:  swoole_process::pop(): msgrcv() failed. Error: Invalid argument[22] in /home/sun/learn/swoole/process/demo.php on line 29 From worker:  PHP Warning:  swoole_process::pop(): msgrcv() failed. Error: Identifier removed[43] in /home/sun/learn/swoole/process/demo.php on line 18 From Master:  PHP Warning:  swoole_process::push(): msgsnd() failed. Error: Invalid argument[22] in /home/sun/learn/swoole/process/demo.php on line 20 Worker Exit, PID=3668 Worker Exit, PID=3667

这就是我的报错，我看这个错误，发现第一个进程是完美执行的，和预先想的一样，错误出在主进程第二次发送消息到消息队列时出现的，主进程的数据发送出错了

哎呀，怎么回事，不明白。

其实故事是这样的

主进程创建两个子进程，这里没问题

主进程向第一个子进程发数据，第一个子进程收到后向主进程回发数据，这里也没问题

主进程再向第二个子进程发数据，好，出问题了，

那么问题来了，第一个子进程做了什么我们不知道的事情？

请看这里子进程临死前做了什么

$status是退出进程的状态码，如果为0表示正常结束，会继续执行PHP的shutdown_function，其他扩展的 清理工作