Dear monks,

Are there any Net::SSH2 experts in the house?

I'm working with an application at work that pulls code and config out of version control, packages it, pushes it up to a target server, and then deploys the package.

Currently, the communication to the remote servers is done with calls to the ssh binary on the local server. I was hoping to replace these invocations of /usr/bin/ssh with a perl module.

I had a look at Net::SSH:Perl, but had a bit of grief installing that due to the dependencies on various math modules. I'm now working with Net::SSH2, which is certainly a lot easier to install, and I'm not sure whether the problems I'm having are expected behaviour, or a bug.

I would like to be able to issue a single command to a server, reading any output to stdout and stderr, and the exit code of the remote process. I'm trying to use the exec method of Net::SSH2::Channel, but at the moment, I'm having trouble reading the output of my command. If I use the channel object as a file handle and read from that, I typically only get a couple of characters back in output before the SSH channel closes. I've tried using the poll and read methods with slightly more success, but I still only get around a couple of lines from say, 'ls -la' in a directory where I would expect to see ~20 lines of output.

I could use the shell method, but then it seems like there's no easy way to separate stderr for stdout, or to retrieve the exit code.

I wonder if this is expected behaviour for exec. To run a remote command, then immediately exit without waiting for output. Can anyone confirm that?

Here's some sample code and output. Am I doing anything obviously wrong?

#!/usr/bin/perl -w

use strict;
use Data::Dumper;

use Net::SSH2;

my $remote_host = 'remote';
my $remote_user = 'vortura';
my $remote_pass = 'xxxxxxx';

my $ssh2 = Net::SSH2->new();

$| = 1;

$ssh2->connect($remote_host) or die "connect failed";
$ssh2->auth_password( $remote_user, $remote_pass ) or die "auth failed
+";

my $chan = $ssh2->channel();
$chan->blocking(0);

my $ret = $chan->exec("ls -la /Users/vortura");

while(<$chan>) {
    print "OUT: ", $_;
}   
print "\n";
print $ret, "\n";

$chan->close;

[download]

Output:

vortura $ ./sshtest.pl 
OUT: total 
0

[download]
'total' in the output being the first few lines of output from ls on the remote system.

Many thanks, R

In reply to Printing Output From Net::SSH2 exec by vortura

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