#!/usr/bin/perl

use FileHandle;
use strict;
use RRDs;

my %devices;
my @extra_devices = ('sda');
my @raids = ('md126');
my $rrddir = '/var/www/apps/diskstats/loke/';
my $devline;

&find_devices;
# print "Monitoring $devline\n";
my $toskip = scalar keys %devices;
$toskip = $toskip + scalar(@extra_devices) + 3;
# print "Skipping $toskip lines\n";
my $fh = FileHandle->new;
open($fh, "-|", "LANG=C iostat -kxd 10 $devline");
unless(eof($fh))
{
        my $line;
        my $linenr = 0;
        while(<$fh>)
        {
		chomp;
		s/^\s+//;
		next unless length;
		$linenr++ if($linenr <= $toskip);
		next unless($linenr > $toskip);
		$line = $_;
		unless($line =~ "Device")
		{
			my ($dev,$rrqm,$wrqm,$rs,$ws,$rk,$wk,$avgrq,$avgqu,$await,$rwait,$wwait,$svctm,$util) = split(/\ +/,$line);
			my $now = time;
			unless(-e "$rrddir/$devices{$dev}.rrd")
			{
				&create("$rrddir/$devices{$dev}.rrd");
			}
			RRDs::update(
				"$rrddir/$devices{$dev}.rrd",
				"$now:$rrqm:$wrqm:$rs:$ws:$rk:$wk:$avgrq:$avgqu:$await:$rwait:$wwait:$svctm:$util",
				);
		}
        }
}
else
{
        close($fh);
}

sub find_devices
{
	foreach my $dev(@extra_devices)
	{
		$devline .= " $dev";
		$devices{$dev} = $dev;
	}
	foreach my $dev(@raids)
	{
		my $device;
		my $devid = 0;
		my $dir = "/sys/block/$dev/slaves";
		opendir(DIR,$dir) or die $!;
		while(my $device = readdir(DIR))
		{
			next if ($device =~ m/^\./);
			my $str = $dev.'_'.$devid;
			$devices{$device} = $str;
			$devline .= " $device";
			$devid++;
		}
		closedir(DIR);
		$devline .= " $dev";
		$devices{$dev} = $dev;
	}
}

sub create
{
	my $outfile	= $_[0];
	RRDs::create
	(
		"$outfile",
		"-s 10",
		'DS:rrqm:GAUGE:20:U:U',
		'DS:wrqm:GAUGE:20:U:U',
		'DS:r:GAUGE:20:U:U',
		'DS:w:GAUGE:20:U:U',
		'DS:read:GAUGE:20:U:U',
		'DS:write:GAUGE:20:U:U',
		'DS:avgrq:GAUGE:20:U:U',
		'DS:avgqu:GAUGE:20:U:U',
		'DS:await:GAUGE:20:U:U',
		'DS:rwait:GAUGE:20:U:U',
		'DS:wwait:GAUGE:20:U:U',
		'DS:svctm:GAUGE:20:U:U',
		'DS:util:GAUGE:20:U:U',
		'RRA:AVERAGE:0.5:1:360',
		'RRA:AVERAGE:0.5:6:1440',
		'RRA:AVERAGE:0.5:30:2014',
		'RRA:AVERAGE:0.5:360:672',
		'RRA:AVERAGE:0.5:8640:365',
	);
	`chmod 640 "$outfile"`;
	`chown admin:www-data "$outfile"`;
}