Re: [Expectperl-discuss] Threading on top of IO::Tty seems to work

[Roland G. <rgi...@cp...>]

Hmm, could be the wait delay in soft/hard_close which is trying to
send signals to the spawned process via "kill". Maybe that also
doesn't work in a thread (like fork()). Could you try closing the
Expect objects in the main thread? Maybe that gets rid of the delay...

Seems a sensible rule to me: "Create and destroy Expect objects only
in the main thread."

BTW, anybody tried to use Net::SSH2 instead of spawning ssh? Net::SSH2
objects are tied filehandles, so they should be usable via
exp_init()...

Cheers!
Roland

On 7/16/07, Bryan Bueter <br...@bu...> wrote:
> > Austin/Roland,
> >
> > Ok, there have been a few threads lately about threading so I thought i
> > would re-visit the issue.  I wrote a script that seems to work, but I
> > would like your opinions on if it really should be working, and/or any
> > snafu's i may run into if I continue doing it this way.
> >
>
> Ok, responding to my own thread...  I've been playing with this because
> even though the login portion is single threaded, it still outperforms
> forking and running in parallel.  However, I think i ran into one bug that
> I am consistently able to re-produce.
>
> My previous script works fine and is pretty quick to spawn and join the
> threads.  However, it seems that if I exit and soft_close()/hard_close()
> the expect object after the thread is joined, it hangs for a couple of
> seconds before joining the first thread.
>
> Here is the script that causes the join() delay.  You can compare this to
> my previous script to demonstrate what I'm talking about.
>
> --- start --->
> #!/usr/bin/perl -w
>
> use strict;
> use threads;
>
> use Expect;
> $Expect::Log_Stdout = 0;
>
> our $prompt = '[>#\$] $';
> my @hosts = ("mythtv", "valhalla", "eldorado" );
> my %hosts_exp;
>
> foreach my $host (@hosts) {
>   print "Getting expect object for $host\n";
>   $hosts_exp{$host} = new Expect;
>
>   $hosts_exp{$host}->log_file("$host.log");
>   $hosts_exp{$host}->spawn("ssh -x $host");
>   $hosts_exp{$host}->expect(5, '-re', $prompt);
> }
>
> my $thread_id = 0;
> my @thread_ids = ();
> my @thread_hosts;
> my @commands = ("uptime", "who", "who am i", "pwd");
> foreach my $host ( keys %hosts_exp ) {
>   $thread_ids[$thread_id] = threads->new("run_threaded",
> $hosts_exp{$host}, $host, @commands);
>   $thread_hosts[$thread_id] = $host;
>
>   $thread_id++;
> }
>
> for (my $t=0; $t<$thread_id; $t++) {
>   print "Joining thread $t (". $thread_hosts[$t] .")\n";
>   my $result = $thread_ids[$t]->join();
>   print "Completed joining thread $t (". $thread_hosts[$t] .")\n";
>
>   if ($result) {
>     $hosts_exp{$thread_hosts[$t]}->send("exit;\n exit;\n exit;\n");
>     $hosts_exp{$thread_hosts[$t]}->soft_close();
>   } else {
>     print "Thread $t returned bad result\n";
>     $hosts_exp{$thread_hosts[$t]}->hard_close();
>   }
>
> }
>
> sub run_threaded {
>   my $exp = shift;
>   my $hostname = shift;
>   my @commands = @_;
>
>   my $result = 0;
>   foreach my $command (@commands) {
>     print "Executing on $hostname: $command\n";
>     $exp->send("$command \n");
>     $result = $exp->expect(5, '-re', $prompt);
>     last if ! $result;
>   }
>
>   return($result);
> }
> <--- end ---
>
> Thanks, please let me know what you think.
>
>
> Bryan Bueter
> http://sourceforge.net/projects/rover
>
>
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