#!/usr/bin/perl
#
# Copyright (C) 2008 Rackspace US, Inc. <http://www.rackspace.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; version 2 dated June,
# 1991.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see http://www.gnu.org/licenses/gpl.txt
#
#
# This plugin is based off of the Connection Usage 
# section of the MySQL Connection Health Page
# 
# http://dev.mysql.com/doc/administrator/en/mysql-administrator-health-connection-health.html
#
# To enable, link mysql_connections to this file. E.g.
#
#    ln -s /usr/share/node/node/plugins/mysql_connections /etc/munin/plugins/mysql_connections
#
# Revision 1.0  2007/08/03
# Created by Justin Shepherd <galstrom21@gmail.com>
#
# Revision 2.0 2013/01/02
# Per user support by anarcat@koumbit.org
#
# Parameters:
#
#   config
#   autoconf
#
# Configuration variables
#
#   mysqlopts     - Options to pass to mysql
#   mysqladmin    - Override location of mysqladmin
#   warning	  - Override default warning limit
#   critical	  - Override default critical limit 
#
#%# family=auto
#%# capabilities=autoconf

use strict;

# Define the mysqladmin paths, and commands
my $MYSQLADMIN = $ENV{mysqladmin} || "mysqladmin";
my $TEST_COMMAND    = "$MYSQLADMIN $ENV{mysqlopts} processlist";
my $MYSQL_VARIABLES = "$MYSQLADMIN $ENV{mysqlopts} extended-status variables";
my $warning = $ENV{warning} || "80";
my $critical = $ENV{critical} || "90";

# Pull in any arguments
my $arg = shift();

# Check to see how the script was called 
if ($arg eq 'config') {
    print_graph_information();
    exit();
} elsif ($arg eq 'autoconf') {
    if (test_service()) { print "yes\n"; }
    else { print "no\n"; }
    exit;
} else {
	# Define the values that are returned to munin
	my ($current, $upper_limit) = (0,0,0);
	
	# Gather the values from mysqladmin
	$current = poll_variables($MYSQL_VARIABLES,"Threads_connected");
	$upper_limit = poll_variables($MYSQL_VARIABLES,"max_connections");

	# Return the values to Munin
	print "current.value $current\n";
	print "limit.value $upper_limit\n";

        my $threads = get_thread_list();
        my %counts = ();
        my ($thread, $user, $count);
        while (($thread, $user) = each %$threads) {
            $counts{$user} = 0 unless defined($counts{$user});
            $counts{$user} += 1;
        }
        while (($user, $count) = each %counts) {
            print "$user.value $count\n";
        }
}


sub poll_variables {
	my $command = shift;
	my $expression = shift;
	my $ret = 0;
	open(SERVICE, "$command |")
  		or die("Coult not execute '$command': $!");
	while (<SERVICE>) {
            my ($field, $value) = (m/(\w+).*?(\d+(?:\.\d+)?)/);
	    next unless ($field);
	    if ($field eq $expression ) {
		$ret = "$value";
	    }
	}
	close(SERVICE);
	return $ret;
}


sub print_graph_information {
print <<EOM;
graph_title MySQL Connections
graph_args --base 1000 --lower-limit 0
graph_vlabel Connections
graph_info The number of current connexions per user.
graph_category mysql
graph_total Total
current.label In Use
current.draw LINE1
current.info The number of current threads connected
current.warning $warning
current.critical $critical
limit.label Maximum
limit.draw LINE1
limit.info The current value of the "max_connections" variable
EOM
my $threads = get_thread_list();
my %seen = ();
my ($thread, $user);
while (($thread, $user) = each %$threads) {
    # display user only once
    if (defined($seen{$user})) {
        next;
    }
    else {
        $seen{$user} = 1;
        print <<EOM;
$user.label Connexions for user $user
$user.info Number of connexions used by user $user
EOM
        print "$user.draw ";
        # if we already printed an entry, make the next ones stacked
        if (scalar %seen) {
            print "STACK\n";
        }
        else {
            print "AREA\n";
        }
    }
            
}

}

sub get_thread_list {
    my %threads = ();
    my $command = 'mysql -N -B -e "SHOW PROCESSLIST;"';
    open(SERVICE, "$command |")
        or die("Could not execute '$command': $!");
    while (<SERVICE>) {
        my ($threadid, $user) = split "\t";
        next unless ($threadid);
        $threads{$threadid} = $user;
    }
    return \%threads;
}


sub test_service {
    my $return = 1;
    system ("$MYSQLADMIN --version >/dev/null 2>/dev/null");
    if ($? == 0)
    {
		system ("$TEST_COMMAND >/dev/null 2>/dev/null");
		if ($? == 0)
		{
		    print "yes\n";
		    $return = 0;
		}
		else
		{
	   		print "no (could not connect to mysql)\n";
		}
    }
    else
    {
		print "no (mysqladmin not found)\n";
    }
    exit $return;
}