#!/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
#   numusers      - Override maximum number of users to display
#   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";
my $numusers = $ENV{numusers} || 10;

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

# Check to see how the script was called 
if ($arg eq 'config') {
    print_graph_information();
} elsif ($arg eq 'autoconf') {
    if (test_service()) { print "yes\n"; }
    else { print "no\n"; }
} else {
    print_graph_data();
}
exit;

sub print_graph_data() {
	# Define the values that are returned to munin

	# Return the values to Munin
        my $counts = count_thread_users();
        my %counts = %{$counts};

        sub valsort {
            return $counts{$a} <=> $counts{$b};
        }
        my $i = 0;
        my $total = 0;
        foreach my $user (sort valsort keys(%counts)) {
            last if $i++ >= $numusers;
            $total += $counts{$user};
            print "$user.value $counts{$user}\n";
        }
        my $other = poll_variables($MYSQL_VARIABLES,"Threads_connected") - $total;
	print "other.value $other\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 per user
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
EOM

my $counts = count_thread_users();
my %counts = %{$counts};
my $stacked = 0;

sub valsort {
    return $counts{$a} <=> $counts{$b};
}
my $i = 0;
foreach my $user (sort valsort keys(%counts)) {
    last if $i++ >= $numusers;
    print <<EOM;
$user.label $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 ($i > 1) {
        print "STACK\n";
    }
    else {
        print "AREA\n";
    }
}

print <<EOM;
other.label Others
other.draw STACK
other.info Other connected threads not in the top $numusers
EOM
}

sub count_thread_users {
    my %counts = ();
    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);
        $counts{$user} = 0 unless defined($counts{$user});
        $counts{$user}++;
    }
    return \%counts;
}

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;
}