如何让 Capture::Tiny 在失败时打印 stderr 和 stdout？

Question

我正在尝试通过 Capture::Tiny 获取命令失败时的输出，

#!/usr/bin/env perl

use strict;
use warnings;
use feature 'say';
use Carp 'confess';
use Capture::Tiny 'capture';

sub execute {
    my $cmd = shift;
    my ($stdout, $stderr, $exit) = capture {
      system( $cmd ); # the script dies here
    };
    if ($exit != 0) { # the script should die here
        say "exit = $exit";
        say "STDOUT = $stdout";
        say "STDERR = $stderr";
        confess "$cmd failed";
    }
    say "STDOUT = $stdout";
    say "STDERR = $stderr";
    say "exit code = $exit";
    return 0
}

execute("ls fakedir");

但问题是当我执行脚本时，

con@V:~/Scripts$ perl execute.pl
"ls fakedir" unexpectedly returned exit value 2 at /home/con/perl5/perlbrew/perls/perl-5.32.0/lib/site_perl/5.32.0/Capture/Tiny.pm line 382.

我得到的只是退出值，它没有提供 fakedir 不存在的有价值信息。也就是说，我只在脚本成功时得到 STDOUT 和 STDERR。

无论我使用 die 还是 confess 我都会遇到同样的问题 -> 脚本不打印输出 $stderr 和 $stdout

我已经按照 How do you capture stderr, stdout, and the exit code all at once, in Perl?, which does what I want, but the author https://metacpan.org/pod/IO::CaptureOutput 上的建议尝试了 IO::CaptureOutput 说“维护者不再推荐此模块 - 请参阅 Capture::Tiny。”这很奇怪，IO::CaptureOutput 似乎工作得更好！

如何让这个脚本在 $stdout、$stderr 和 $exit 印有 confess 的情况下消失？

Answer 1

Capture::Tiny is working properly. system is raising an error as if use autodie "system" 已开启。 Capture::Tiny 只捕获 STDOUT 和 STDERR，它不捕获错误。

您必须进行错误处理。你可以用一个 eval 块来捕获它。

    my ($stdout, $stderr, $exit) = capture {
        eval {
            system( $cmd );
        }
    };
    if (my $e = $@) { # the script should die here
        # Can't get the system exit code from autodie.
        #say "exit = $exit"
        say "STDOUT = $stdout";
        say "STDERR = $stderr";
        confess "$cmd failed";
    }
    else {
        say "STDOUT = $stdout";
        say "STDERR = $stderr";
        say "exit code = $exit";
        return 0;
    }

在这种特定情况下，您已经在做 autodie 所做的事情。关闭捕获块内的 autodie 更简单。

    my ($stdout, $stderr, $exit) = capture {
        no autodie "system";
        system( $cmd );
    };
    if ($exit) {
        say "exit = $exit";
        say "STDOUT = $stdout";
        say "STDERR = $stderr";
        # the script should die here
        confess "$cmd failed";
    }
    else {
        say "STDOUT = $stdout";
        say "STDERR = $stderr";
        say "exit code = $exit";
        return 0;
    }

或者，既然你无论如何都会出错，你可以让 autodie 做它的事情。

    my ($stdout, $stderr, $exit) = capture {
        system( $cmd );
    };
    say "STDOUT = $stdout";
    say "STDERR = $stderr";
    say "exit code = $exit";

如何让 Capture::Tiny 在失败时打印 stderr 和 stdout？

How to get Capture::Tiny to print stderr and stdout upon failure?

perl