Andy16 has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I'd like to use a OpenSSH connection in a MCE worker thread.

Doing so - the worker thread just exists after the "new".

First debugging:
not giving user/pwd it stops showing the password prompt.
giving user and pwd to the new - it crashes.

Is there any hassle with signals?
Any way out of that or how to do more debugging?

thanks for help, monks! :-> 


$self->sendto('stdout', "child($wid): doing ssh\n");     

$ssh = Net::OpenSSH->new(
    $device, 
    user => $sshuser, 
    passwd => $sshpwd,
    master_opts => [-o => "StrictHostKeyChecking=no"],
    master_stderr_discard => 1
);

$self->sendto('stdout', "child($wid): did ssh - not shown!!! \n");

[download]



and after some more digging: if I
use IO::Pty;
in the main prog already - everything is fine!
So there is not a signal but a coding issue in loading that lib during runtime..

Replies are listed 'Best First'.
Re: using Net::OpenSSH in a MCE worker thread
by salva (Canon) on Jun 28, 2013 at 10:01 UTC
    Activate the module debugging mode... 
    $Net::OpenSSH::debug = -1;

    [download]
    and post here what you get.
[reply]
[d/l]
      Hi all,

      MCE has gone through several revisions since the time the OP tested this. I tested without IO::Pty on my box. Amazingly, running (yum install perl-Net-OpenSSH) installed the package without checking the perl-IO-Tty dependency.

      Workers in older MCE revisions closed STDOUT/STDERR prior to exiting. That was fix some time back.

      $ ./mce_openssh.pl
child(1): doing ssh
unable to load Perl module IO::Pty: Can't locate IO/Pty.pm in @INC (@I
+NC contains: /media/psf/shm/trunk/examples/../lib /usr/local/lib64/pe
+rl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/pe
+rl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at (eval 10) lin
+e 1, <__ANONIO__> line 2.
 at /usr/share/perl5/vendor_perl/Net/OpenSSH.pm line 756.

      [download]

      Btw, the script works after installing IO::Tty (yum install perl-IO-Pty).

      my $sshuser = 'remote_userid';
my $sshpwd  = 'remote_passwd';
my $device  = 'remote_device';

use MCE::Flow max_workers => 1;
use Net::OpenSSH;

mce_flow sub {
   my $wid = MCE->wid;

   MCE->sendto('stdout', "child($wid): doing ssh\n");

   my $ssh = Net::OpenSSH->new(
      $device,
      user => $sshuser,
      passwd => $sshpwd,
      master_opts => [-o => "StrictHostKeyChecking=no"],
      master_stderr_discard => 1
   );

   MCE->sendto('stdout', "child($wid): did ssh - not shown!!! \n");

};

      [download]

      In summary, STDERR output is no longer lost with current MCE releases.

[reply]
[d/l]
[select]
      Hi - sorry, but
      => debug did not do any lines
      => no furhter message than "just gone" ....

      meanwhile (see above) I'm sure it is realted to an eval loading a missing pm...

      thanks!
[reply]

        taken from OpenSSH.pm


        sub _load_module {
    my ($module, $version) = @_;
    $loaded_module{$module} ||= do {
        do {
            local ($@, $SIG{__DIE__});
            eval "require $module; 1"
        } or croak "unable to load Perl module $module";
        1
    };
    if (defined $version) {
        local ($@, $SIG{__DIE__});
        my $mv = eval "\$${module}::VERSION" || 0;
        (my $mv1 = $mv) =~ s/_\d*$//;
        croak "$module version $version required, $mv is available"
            if $mv1 < $version;
    }
    1
}

        [download]


        somewhere in here it breaks... if pm not preloaded and in MCE context.

[reply]
[d/l]
Re: using Net::OpenSSH in a MCE worker thread
by kcott (Archbishop) on Jun 28, 2013 at 09:20 UTC
[reply]

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