#!/bin/perl
use strict;
use warnings;
use Getopt::Long;
use DBI();

my $opt_crit = 0;
my $opt_warn = 0;
my $opt_query = '';
GetOptions('critical=i' => \$opt_crit, 'warning=i' => \$opt_warn);

sub ERROR {
  print "UNKNOWN - database connection error.\n";
  exit 3;
}

my $dsn = "DBI:mysql:mysql_read_default_file=/etc/nagios/.my.cnf;mysql_connect_timeout=15";
my $dbh = DBI->connect($dsn) || ERROR();
my $sth = $dbh->prepare("show status like 'Threads_connected';") || ERROR();
my $count = 0;

$sth->execute();
my $ref = $sth->fetchrow_hashref();
$count = $ref->{'Value'};

if($count >= $opt_crit) {
  print "CRITICAL - $count client connection threads.\n";
  exit 2;
} elsif($count >= $opt_warn) {
  print "WARNING - $count client connection threads.\n";
  exit 1;
} elsif($count >= 0) {
  print "OK - $count client connection threads.\n";
  exit 0;
} else {
  print "UNKNOWN - couldn't get connection threads.\n";
  exit 3;
}