#!/usr/bin/perl
# -*- perl -*-

# Author Rodolphe Quiédeville <rodolphe@quiedeville.org>
# Licence : GPLv2
# Code based on tomcat_volume plugin by 
# Rune Nordbøe Skillingstad <runesk@linpro.no>

=head1 NAME

geowebcache_volume - Plugin to monitor the cache hit ratio of GeoWebCache
servers.

version 1.0.1

=head1 CONFIGURATION

The following environment variables are used by this plugin

=over 4

=item timeout

Connection timeout

=item url

Override default status-url

=item ports

HTTP port numbers

=back

=head2 CONFIGURATION EXAMPLE

 [geowebcache_ratio]
  env.url      localhost:%d/geoserver/gwc
  env.ports    8081

=head1 AUTHOR

Rodolphe Quiédeville <rodolphe@quiedeville.org>

=head1 USAGE

Needs access to
http://localhost:8080/gwc (or modify the address for another host).

If geowebcache is used inside GeoServer the url will be
http://localhost:8080/geoserver/gwc

GeoWebCache 1.2 or higher.

Tip: To see if it's already set up correctly, just run this plugin
with the parameter "autoconf". If you get a "yes", everything should
work like a charm already.

=head1 MAGIC MARKERS

 #%# family=contrib
 #%# capabilities=autoconf

=cut

use strict;

my $ret = undef;

if(!eval "require LWP::UserAgent;") {
    $ret = "LWP::UserAgent not found";
}

my $URL      = exists $ENV{'url'}      ? $ENV{'url'}      : "http://127.0.0.1:%d/geowebcache/home";
my $PORT     = exists $ENV{'ports'}    ? $ENV{'ports'}    : 8080;
my $TIMEOUT  = exists $ENV{'timeout'}  ? $ENV{'timeout'}  : 30;

my $url = sprintf $URL, $PORT;

if(exists $ARGV[0] and $ARGV[0] eq "autoconf") {
    if($ret) {
	print "no ($ret)\n";
	exit 0;
    }
    my $au = LWP::UserAgent->new(timeout => $TIMEOUT);
    my $response = $au->request(HTTP::Request->new('GET',$url));
    if($response->is_success and $response->content =~ /GWC Home/im) {
	print "yes\n";
	exit 0;
    } else {
	print "no geowebcache found\n";
	exit 0;
    }
}

if(exists $ARGV[0] and $ARGV[0] eq "config") {
    print "graph_title GeoWebCache cache hit ratio\n";
    print "graph_args --base 1000\n";
    print "graph_vlabel %\n";
    print "graph_category loadbalancer\n";
    print "ratio.label percent\n";
    print "ratio.type GAUGE\n";
    print "ratio.max 100\n";
    print "ratio.min 0\n";
    print "ratio.draw AREA\n";
    print "ratio.colour FFCC00\n";
    exit 0;
}

my $ua = LWP::UserAgent->new(timeout => $TIMEOUT);
my $response = $ua->request(HTTP::Request->new('GET',$url));

if ($response->content =~ '<tr><td colspan="5"> </td></tr><tr><td colspan="2">Cache hit ratio:</td><td colspan="3">(\d\d?\.?\d+)% of requests</td></tr>' ) {
    print "ratio.value " . $1;
} else {
    print "ratio.value U\n";
}

# vim:syntax=perl