#!/usr/bin/perl
#
# copyright Martin Pot 2006-2009
# http://martybugs.net/electronics/tempsensor/
#
# rrd_tempsensors.pl

use RRDs;

# define location of rrdtool databases
my $rrd = '/var/lib/rrd';
# define location of images
my $img = '/var/www/rrdtool';

# process data for each interface (add/delete as required)
&ProcessSensor(0, "sensor 1");
&ProcessSensor(1, "sensor 2");
&ProcessSensor(2, "sensor 3");


sub ProcessSensor
{
# process sensor
# inputs: $_[0]: sensor number (ie, 0/1/2/etc)
#	  $_[1]: sensor description 

	# get temperature from sensor
	my $temp = `/usr/bin/digitemp -t $_[0] -q -c /etc/digitemp.conf -o%C`;

	# remove eol chars
	chomp($temp);

	print "sensor $_[0]: $temp degrees C ($_[1])\n";

	# if rrdtool database doesn't exist, create it
	if (! -e "$rrd/temp$_[0].rrd")
	{
		print "creating rrd database for temp sensor $_[0]...\n";
		RRDs::create "$rrd/temp$_[0].rrd",
			"-s", "60",
			"DS:temp:GAUGE:240:U:U",
			"RRA:AVERAGE:0.5:1:2016",
			"RRA:AVERAGE:0.5:6:1344",
			"RRA:AVERAGE:0.5:24:2190",
			"RRA:AVERAGE:0.5:144:3650";
	}
	if ($ERROR = RRDs::error) { print "$0: failed to create $_[0] database file: $ERROR\n"; }

	# check for error code from temp sensor
	if (int $temp eq 85)
	{
		print "failed to read value from sensor $_[0]\n";
		$temp = "U";
	}
	
	# insert values into rrd
	RRDs::update "$rrd/temp$_[0].rrd",
		"-t", "temp",
		"N:$temp";
	if ($ERROR = RRDs::error) { print "$0: failed to insert $_[0] data into rrd: $ERROR\n"; }
}

&CreateGraph($_[0], "day", $_[1]);
&CreateGraph($_[0], "week", $_[1]);
&CreateGraph($_[0], "month", $_[1]);
&CreateGraph($_[0], "year", $_[1]);


sub CreateGraph
{
# creates graph
# inputs: $_[0]: n/a
#         $_[1]: interval (ie, day, week, month, year)
#         $_[2]: graph description

        RRDs::graph "$img/temps-$_[1].png",
                "-s -1$_[1]",
                "-t DS18S20 temperature sensors :: last $_[1] (1 minute samples)",
		"--lazy",
                "-h", "200", "-w", "800",
		"-l", "0",
                "-a", "PNG",
                "-v degrees Celsius",
                "--slope-mode",
		"--color", "SHADEA#ffffff",
		"--color", "SHADEB#ffffff",
		"--color", "BACK#ffffff",
		"--color", "CANVAS#ffffff",
                "DEF:temp0=$rrd/temp0.rrd:temp:AVERAGE",
		"DEF:temp1=$rrd/temp1.rrd:temp:AVERAGE",
		"DEF:temp2=$rrd/temp2.rrd:temp:AVERAGE",
		"LINE2:temp0#33CC00:sensor 1\\:         ",
		"GPRINT:temp0:MIN:    Min\\: %5.2lf",
		"GPRINT:temp0:MAX:   Max\\: %5.2lf",
		"GPRINT:temp0:AVERAGE:   Average\\: %5.2lf",
		"GPRINT:temp0:LAST:   Current\\: %5.2lf degrees Celsius\\n",
		"LINE2:temp1#990000:sensor 2\\:         ",
		"GPRINT:temp1:MIN:    Min\\: %5.2lf",
		"GPRINT:temp1:MAX:   Max\\: %5.2lf",
		"GPRINT:temp1:AVERAGE:   Average\\: %5.2lf",
		"GPRINT:temp1:LAST:   Current\\: %5.2lf degrees Celsius\\n",
		"LINE2:temp2#00FF00:sensor 3\\:         ",
		"GPRINT:temp2:MIN:    Min\\: %5.2lf",
		"GPRINT:temp2:MAX:   Max\\: %5.2lf",
		"GPRINT:temp2:AVERAGE:   Average\\: %5.2lf",
		"GPRINT:temp2:LAST:   Current\\: %5.2lf degrees Celsius\\n";
        if ($ERROR = RRDs::error) { print "$0: unable to generate sensor $_[0] $_[1] graph: $ERROR\n"; }
}