tcp_table

I have not had time to do the test “postfix memcached patch” because there are no idle servers that can be used for the experiment. instead, I’ve made a tutorial how to integrate memcached as a “postfix lookup table” with the help of tcp_table and a simple perl script.

Indeed, tcp_table “table lookup protocol” is one of the most powerful tools as well as the regexp and pcre, in my opinion. although client-server connection is not protected and and the server is not authenticated.

yes, I did a lot of experiments using tcp_table and perl scripts. it made me realize that I can do almost everything I need and make postfix as my favorite MTA.

Things required:

• perl Cache::Memcached module
• memcached
• postfix with tcp_table support

OK, first we create a simple perl script that allows you to handle the protocols of tcp_table. let’s call it memc.pl

#!/usr/bin/perl
use strict;
use warnings;
use Sys::Syslog qw(:DEFAULT setlogsock);
use Cache::Memcached;

# Configure the memcached server
my $memd = new Cache::Memcached {
            'servers' => [ '127.0.0.1:11211' ],
};

#
# Initalize and open syslog.
#
openlog('postfix/memcached','pid','mail');

sub qrymemc {
        return unless /^get\s+(.+)/i;
        my $kmemc = lc($1);
        chomp($kmemc);
        trim($kmemc);
        my $vmemc = $memd->get($kmemc);
        if (defined $vmemc) {
                return ($kmemc,$vmemc);
        }
        return;
}

sub trim{
        $_[0]=~s/^\s+//;
        $_[0]=~s/\s+$//;
        return;
}

#
# Autoflush standard output.
#
select STDOUT; $|++;

while (<>) {
        chomp;
        if (/^get\s+(.+)/i) {
                my $data = lc($1);
                my @res = qrymemc($data);
                syslog("info","data: %s", $data);
                if (@res) {
                        chomp(@res);
                        print "200 $res[1]\n";
                        syslog("info","Found: key = %s, value = %s", $res[0], $res[1]);
                        next;
                }
        }
        print "200 DUNNO\n";
}