01 #!/usr/bin/perl
02 #############################
03 # rrdload - Measure CPU Load
04 # Mike Schilli, 2004
05 # (m@perlmeister.com)
06 #############################
07 use warnings;
08 use strict;
09 
10 use RRDs;
11 use Getopt::Std;
12 
13 getopts("ug", \my %opts);
14 
15 my $DB     = "/tmp/load.rrd";
16 my $SERVER = "/www/htdocs";
17 my $UPTIME = "uptime";
18 
19 if(! -f $DB) {
20   RRDs::create($DB, 
21     "--step=300",
22     "DS:load:GAUGE:330:U:U", 
23     "RRA:MAX:0.5:1:288",
24     "RRA:MAX:0.5:12:168",
25     "RRA:MAX:0.5:288:365",
26   ) or die "Create error: " .
27            "($RRDs::error)";
28 }
29 
30 if(exists $opts{u}) {
31   my $uptime = `$UPTIME`;
32   my ($load) = 
33     ($uptime =~ /(\d\.\d+)/);
34 
35   RRDs::update($DB, 
36     time() . ":$load") or
37       die "Update error: " .
38           "($RRDs::error)";
39 }
40 
41 if(exists $opts{g}) {
42   RRDs::graph(
43    "$SERVER/load.png",
44    "--vertical-label=" .
45      "Load perlmeister.com",
46    "--start=" . 
47      rrd_start_time(),
48    "--end=" . time(), 
49    "DEF:myload=$DB:load:MAX",
50    "LINE2:myload#FF0000") or
51      die "graph failed " .
52          "($RRDs::error)";
53 }
54 
55 #############################
56 sub rrd_start_time {
57 #############################
58   my ($start, $step, $names,
59       $data) = 
60      RRDs::fetch($DB, "MAX");
61 
62   foreach my $line (@$data) {
63     if(!defined $line->[0]) {
64       $start += $step;
65       next;
66     }
67     return $start;
68   }
69 }