in reply to Net::SSH::Perl, Net::SSH::Expect crashes script if host is unreachable

Net::SSH::Expect sets up a timeout handler, which croaks (i.e. dies, stopping the script) in case it gets called: 

     # line 207
     [ timeout                               => sub
             {
                     croak SSH_AUTHENTICATION_ERROR . " Login timed ou
+t. " .
                     "The input stream currently has the contents bell
+ow: " .
                     $self->peek();
             }
     ]

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So, wrap the login call in an eval { } block (Perl's way of catching exceptions), e.g. like this: 

  eval {
      $loginOutput = $ssh->login();
  };
  if ($@) {
      myAuditLog(LOG,"Login has failed: $@");
  }

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Re^2: Net::SSH::Perl, Net::SSH::Expect crashes script if host is unreachable
by Anonymous Monk on May 08, 2012 at 13:57 UTC
    i specified timeout => 20 in the constructor, and problem was solved.As mine was slow network i took 20seconds as timeout.
[reply]

      I ended up trying the long timeout thing and it did work but it would allow the value(in seconds) of the timeout to pass in between commands.

      For example: timeout = 5

      It will take 5 seconds to login, then it will take 5 seconds for the first command to be issued, then another 5 seconds for the next command, so on so forth. and finally 5 seconds for the close command.

      So, in the end, the process ends up spending way too much time per device and therefore this was a show stopper for me.

      The solution for me (since Salva's solution didn't work for me in this thread Net::OpenSSH multiple commands ) was to remove the username/password login and make it use public-key authentication. So far (knock on wood) I haven't had this problem again and the delay in between the commands is gone. This seems to finally round off this solution for me. Here is a sample of code I used to make this work. (taken from it's documentation)

      # Starting ssh without password
# 1) run the constructor
my $ssh = Net::SSH::Expect->new (
  host => "myserver.com", 
  user => 'bnegrao', 
  raw_pty => 1
);
# 2) now start the ssh process
$ssh->run_ssh() or die "SSH process couldn't start: $!";
        
# 3) you should be logged on now. Test if remote prompt is received:
($ssh->read_all(2) =~ />\s*\z/) or die "where's the remote prompt?"

$ssh->exec("whoami");
$ssh->exec("/sbin/ifconfig");
$ssh->exec("ls /");

ssh->close();

      [download]

      I know this post is old but I hope this helps someone anyway.

[reply]
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