multithreading - 从 Perl 线程运行 bash 脚本

Question

我的脚本应该有 n 个子例程 (my_proc) 同时运行，每个子例程都运行 bash 脚本，并且一个子例程 (check_procs) 检查子例程是否已完成。

use strict;
use threads;
use threads::shared;

my %proc_status :shared;
my %thr;

foreach my $i (1,2,3,4) {
    $proc_status{$i}=0;
}

sub my_proc {
    my $arg=shift(@_);
    while (1) {
         sleep(2);
         print "Proc $arg Started\n";
         #exec("/bin/bash","sleep_for_10_sec.bash") or die("Can't exec");   # case 1
         #`sleep_for_10_sec.bash &`;                                        # case 2      

         print "Proc $arg Finished\n";
         {
         lock(%proc_status);
         $proc_status{$arg}=1;
         }
    }
}

sub check_procs {
    my $all_finished;
    while (! $all_finished) {
            sleep 5;
            print "CHECK: \n";
            $all_finished=1;
            foreach my $num (1,2,3,4) {
                    if ($proc_status{$num} == 1) {
                            print "CHECK: procedure $num has finished\n";
                    } else {
                        $all_finished=0;
                    }
            }
    }
    print "All jobs finished\n";
}

foreach my $num (1,2,3,4) {
    $thr{"$num"} = new threads \&my_proc,$num;
}

my $thr_check= new threads \&check_procs;
$thr_check->join();

这是 sleep_for_10_sec.bash

ls
# bunch of other stuff 
sleep 10
echo "finished sleep"

我不希望my_proc subs等待“sleep_for_10_sec.bash”命令被执行，浏览后我发现#case1或# case2 应该可以工作，但它们都失败了。

#case1 的输出:

 Proc 1 Started
 [ls result]
 finsihed sleep

#case2 的输出:

Proc 1 Started
Proc 2 Started
Proc 3 Started
Proc 4 Started
CHECK:
CHECK:
Proc 4 Finished
Proc 2 Finished
Proc 3 Finished
Proc 1 Finished
Proc 3 Started
Proc 1 Started
Proc 2 Started
Proc 4 Started
CHECK:
CHECK: procedure 1 has finished
CHECK: procedure 2 has finished
CHECK: procedure 3 has finished
CHECK: procedure 4 has finished

但我期望这样的事情:

 Proc 1 Started
 Proc 2 Started
 Proc 3 Started
 Proc 4 Started
 Proc 1 Finished
 Proc 1 Started
 Proc 3 Finished
 Proc 3 Started
 Proc 4 Finished
 Proc 4 Started
 Proc 2 Finished
 Proc 2 Started
 CHECK:
 CHECK:
 CHECK:
 CHECK: procedure 1 has finished
 CHECK: procedure 2 has finished
 CHECK: procedure 3 has finished
 CHECK: procedure 4 has finished

实际上，如果将输出重定向到“> log”，我会得到想要的结果，但无论如何之后:

 Proc 1 Started
 Proc 2 Started
 Proc 3 Started
 Proc 4 Started

它等待“sleep_for_10_sec.bash”完成。

这是我使用“thread”和“exec”的第一个项目，有人可以帮助我吗？

Answer 1

exec 不应与线程结合使用。 exec 在当前进程中启动一个新程序，因此当您从一个线程调用 exec 时，线程正在执行的程序就会消失。由于线程没有要执行的程序，因此 exec 也会杀死线程。

我不清楚为什么情况 2 不起作用(编辑:请参阅下面 ikegami 的评论)。我认为它会启动该进程，在后台运行它，并允许 Perl 线程立即继续。它似乎没有这样做，但这段代码会:

system("/bin/bash sleep_for_10_sec.bash &");        # case 3