Net:SSH::Expect and microcom?

[Anonymous Monk]

O wise monks,

I have run into an issue at work where I need to automate the following:

SSH to an element

Run "Microcom /tmp/dev/mux1"

send "AT+CSQ" to that program

Retrieve the output in a variable in my script

I've accomplished the first (SSH to element and run command) but when it comes to actually sending anything to the interface and retrieve the output, I just cant get it to work.

Relevant part of the code:

$ssh->exec("microcom /tmp/dev/mux1");
$ssh->send("AT+CSQ");
$ssh->waitfor('^\+CSQ', 3) or warn "No output!";
$myOutput = $ssh->match();
print "CSQ result: $myOutput";

I've tried with ssh->exec("AT+CSQ") as well with no success. It simply warns on "No output!"

Anyone done something similar before and can provide me with a hint or two on how to overcome this obstacle?

If only I could pass the AT command directly on the commandline, but alas, thats not possible. :-(

Thanks in advance!

[salva]

Using Net::OpenSSH and Expect:

# untested
use Net::OpenSSH;

my $ssh = Net::OpenSSH->new(...);
my ($pty, $pid) = $ssh->open2pty('microcom /tmp/dev/mux1');

my $exp = Expect->init($pty);
$exp->send("AT+CSQ\r\n");
$exp->expect($timeout,
             [qr/^OK$/ => sub { ... }],
             [qr/^ERROR$/ => sub { ... }]);
$exp->soft_close();
waitpid($pid, 0);

[Anonymous Monk]

Thanks, but it doesnt work. I am experiencing some very odd behaviour with the suggested snipped.

When run manually, the AT command returns to OK within 500ms. Since the RegEx would match and it still times out, I believe it safe to conclude that it still doesnt pass in the AT command.

More important is the fact that no matter what timeout I set, it throws the warning after ~2 seconds. I've set 50 seconds in the example below:

print "Before timeout: " . localtime() . "\n";
my $timeout = 50;
$exp->expect($timeout,
    [qr/^OK$/ => sub { print "Success!\n"; }],
    [qr/^ERROR$/ => sub { print "Failure!\n"; }]) or warn "Timeout!";
print "After timeout: " . localtime() . "\n";

and the output I get from the above:

Before timeout: Tue Nov  8 03:31:02 2011
Timeout! at getdbm.pl line 18.
After timeout: Tue Nov  8 03:31:04 2011

Am I experiencing a bug here, or am I (still) an idiot?

[salva]

Maybe you have to wait for microcom to settle before sending anything. Try sleeping for 1 second before sending the modem command.

[williams554]

Hello,

You need to tell it newline or return.

$ssh->send("AT+CSQ\n"); or
$ssh->send("AT+CSQ\r");
Also, you can log what's going on
string log_file
Used as argument to the internal Expect->log_file() method.
The default is no logfile.

Good luck, Rob

[Anonymous Monk]

I've gotten a bit closer, but not quite there yet

#!/usr/bin/perl

use strict;
use Net::SSH2;

my $ssh = Net::SSH2->new();

$ssh->connect('10.10.10.10') or die;

if ($ssh->auth_password('zzz','xxx')) {
  $ssh->debug(1);
  my $chan = $ssh->channel();
  $chan->shell();
  print $chan "microcom /tmp/dev/mux1\n";
  sleep(10);
  print $chan "AT+CSQ";
  select(undef,undef,undef,3.0);
  my ($len, $buf);
  print $buf while ($len = $chan->read($buf,1)) > 0;
  $chan->close;
} else {
  warn "auth failed.\n";
}

This one clearly shows me that the AT+CSQ is not passed on - when connecting to the modem, it will report "ERROR" after ~20 seconds of nothing going on. And it does just that. Any ideas on how to move on from here?