#!/usr/bin/perl
#
# loadavg.pl - Very silly script to measure the size of my email
# "inbox", then plot that size over time to display my "load average"
# Intended to run periodically (maybe once per hour) from cron.  Needs
# 'date', 'grep', 'gnuplot', probably some other things.
#
# To do: I get a huge amount of junk (mailing lists, mail generated by 
# automated processes, etc.) that gets immediately deleted when I read
# it.  This graph would be much smoother and more meaningful if it only
# plotted each day's minimum value or something like that.
#
# Copyright (C) 2002 Michael A. Dickerson.  Copying, modification, or
# redistribution are permitted under the terms of the Artistic License
# as published by the Open Source Initiative.  This is OSI Certified
# Open Source Software; see http://www.opensource.org.
#
# Created 20 Aug 2002 by M. Dickerson
#  3 Sep 02 MAD: changed y range from [0,100] to [0,50]

use strict;

my $date="/usr/bin/date";
my $grep="/usr/bin/grep";
my $home="/home/mikey";

my $inbox="$home/.mail";
my $data_file="$home/.inbox_size";
my $week_plot="$home/www/week.png";
my $month_plot="$home/www/month.png";

my @month = qw/Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec/;

my $size=`$grep -c "^From " $inbox`;
chomp $size;

# some fancy date arithmetic

my $now=time();
(my $sec, my $min, my $hour, my $day, my $mon, my $year) 
    = localtime($now - (86400 * 7));
my $lastweek = sprintf("%d %s %d %d:%02d:%02d",
		       $day, $month[$mon], $year + 1900, $hour, $min, $sec);
($sec, $min, $hour, $day, $mon, $year) = localtime($now - (86400 * 30));
my $lastmonth = sprintf("%d %s %d %d:%02d:%02d",
			$day, $month[$mon], $year + 1900, $hour, $min, $sec);
($sec, $min, $hour, $day, $mon, $year) = localtime($now);
$now = sprintf("%d %s %d %02d:%02d:%02d",
	       $day, $month[$mon], $year + 1900, $hour, $min, $sec);

if (0) { # for if you need to debug the date arithmetic..
    print "now: $now\n";
    print "lastweek: $lastweek\n";
    print "lastmonth: $lastmonth\n";
    exit 0;
}

open DAT, ">>$data_file" or die("can't open $data_file: $!");
print DAT "$now $size\n";
close DAT or die("can't close $data_file: $!");

open PLOT, "|/usr/local/bin/gnuplot" or die("can't run gnuplot: $!");
print PLOT <<EOF;
set xdata time
set timefmt "%d %b %Y %H:%M:%S"
set format x "%d %b"
set xrange ["$lastweek" : "$now"]
set yrange [0 : 50]
set terminal png small color
set output "$week_plot"
plot "$data_file" using 1:5 with lines
set xrange ["$lastmonth" : "$now"]
set output "$month_plot"
plot "$data_file" using 1:5 with lines
EOF

close PLOT or die("can't close gnuplot: #!");