munin-value.cgi

#!/usr/bin/perl
# stsimb sep 2014
# webservice to fetch any munin metric via http
# install in muninhost /var/www/cgi-bin and use via apache
# e.g. http://muninhost/cgi-bin/munin-value.cgi?hostname=it-web-04.cloud.forthnet.prv&plugin=cpu&metric=user

use CGI qw(:standard);

my $hostname = lc(param("hostname"));		# hostname
my ($host, $dom) = split (/\./, $hostname, 2);	# autodetect domain from hostname
my $domain = lc(param("domain")) || $dom;	# but allow to override using param
my $plugin = param("plugin");			# plugin
my $metric = param("metric");			# metric

my $cmd ="";

print header;					# print standard cgi header

if ($hostname eq "") {
	$cmd = "echo need hostname";
} elsif ($plugin eq "") {
	$cmd = "echo list | /usr/bin/nc -w 5 $hostname 4949";
	print "available plugins for $hostname<pre>";
} elsif ($metric eq "") {
	$cmd = "echo fetch $plugin | /usr/bin/nc -w 5 $hostname 4949 | /usr/bin/awk '{print \$1}' | /bin/sed -e 's/.value\$//g'";
	print "available metrics for $plugin plugin of $hostname<pre>";
} else {
	$cmd = "echo fetch $plugin | /usr/bin/nc -w 30 $hostname 4949 | /bin/grep \"^$metric.value\" | /usr/bin/awk '{print \$2}'";
}

$value = `$cmd`;
print "$value";