Re: [Expectperl-discuss] retry after spawned process fails

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

You can avoid all that hassle by doing the TCP connect directly in perl 
(directly with Socket or maybe with a little help from a nice CPAN 
module) and not in a spawned netcat. Expect doesn't need to spawn a 
program, it can also take a filehandle and work on that.

Hope this helps,

Roland

Ken Irving schrieb:
> Using Expect.pm 1.15, occasionally the spawned process fails for unknown
> reasons. Up to now we just exit the program, but I'd like to give it
> another try.  I'm not clear on what exactly to retry, though.
>
> The code segment is currently:
>
>     my $exp = Expect->new();
>     $exp->raw_pty(1);
>     $exp->debug($debug);
>     $exp->log_file($nc_log) if $nc_log;
>     $exp->spawn("/bin/nc", $host, $port)
>         or die "Cannot spawn nc: $!\n";
>     $exp->expect(10, '-re', 'CoraScript.*$')
>         or log_session('NO_CORA_CMD'); # log_session() invokes die()
>
> The process is spawned, but the subsequent expect() times out.
>
> I could perhaps do something like the following, i.e., just abandon the
> Expect object (not tested):
>
>     my $exp;
>     my $retries = 3;
>     while ( $retries ) {
>         $retries -= 1;
>         $exp = Expect->new();
>         $exp->raw_pty(1);
>         $exp->debug($debug);
>         $exp->log_file($nc_log) if $nc_log;
>         $exp->spawn("/bin/nc", $host, $port)
>             or die "Cannot spawn nc: $!\n";
>         break if $exp->expect(10, '-re', 'CoraScript.*$');
>         $exp->hard_close();
>         undef $exp;
>         }
>     log_session('NO_CORA_CMD') unless $exp;
>     ...
>
> But is there a cleaner or better way to approach this?
>
> Thanks for any hints or pointers, examples, etc.
>
> Ken
>
>