Reviving an old thread…

I came here because I also wanted to connect to a mysql DB running on a remote host, not publicly exposing its port.

My solution is as follows:

1. Set up the environment to contain the required information
2. Have a module which opens a tunnel and connects to the DB

This is the module:

package TUNNEL_DB;

use DBI;
use Net::OpenSSH;

my $DB_PASSWORD= $ENV{DB_PASSWORD};
my $DB_USERNAME= $ENV{DB_USERNAME};
my $DB_DATABASE= $ENV{DB_DATABASE};
my $DB_PORT    = $ENV{DB_PORT};
my $REMOTE_HOST= $ENV{REMOTE_HOST};
my $LOCAL_PORT = $ENV{LOCAL_PORT};

sub new {
    my $class= shift;
    $class= ref $class || $class;

    my $ssh = Net::OpenSSH->new($REMOTE_HOST, master_opts => "-L127.0.
+0.1:$LOCAL_PORT:localhost:$DB_PORT");
    $ssh->error and
    die "Couldn't establish SSH connection: ". $ssh->error;

    my $dsn = "DBI:mysql:database=$DB_DATABASE;host=127.0.0.1;port=$LO
+CAL_PORT";
    my $dbh = DBI->connect($dsn, $DB_USERNAME, $DB_PASSWORD);
    my $self= {
        dbh => $dbh,
        ssh => $ssh,
    };
    bless $self, $class;
    return $self;
}

sub disconnect {
    my ($self)= @_;
    $self->{dbh}->disconnect;
    $self->{ssh}->system('exit');
}

sub DESTROY {
    disconnect();
}

sub AUTOLOAD {
    my $self= shift;

    return if $AUTOLOAD=~ /::DESTROY$/;

    $AUTOLOAD=~ s/^.*:://;
    $self->{dbh}->$AUTOLOAD(@_);
}

1;
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And this is the example code, using the module:

#!/usr/local/bin/perl
use strict;
use warnings;
use DBI;
use TUNNEL_DB;

my $dbh= TUNNEL_DB->new();

my $sth = $dbh->prepare(
    'SELECT id,domain from domains')
    or die "prepare statement failed: $dbh->errstr()";

$sth->execute() or die "execution failed: $dbh->errstr()";

print $sth->rows . " rows found.\n";

while (my $ref = $sth->fetchrow_hashref()) {
    print "Found a row: id = $ref->{'id'}, fn = $ref->{'domain'}\n";
}

$sth->finish;

$dbh->disconnect;
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So the whle connection is defined in the environment.

After connecting, thanks to the autoload, my object can be handled like any DBI object. No special steps are required and my script doesn't even know there is a tunnel in-between.