#!/usr/bin/perl -w
#-wT
#
# check_rrd plugin for nagios (or rather check_rrd but using the current rrd rather than cricket libraries)
#
# usage:
#    check_rrd rrdfile perlexp_warn perlexp_crit perlexp_default [ds]
#
# Checks data from an RRD file.
#
# Based off the check_rrd_data.pl and the example code in the rrdtool dist.
#
# The Perl expressions are expressions to be evaluated in the following cases:
#
# - perlexp_crit. The first one, to check if there is a critical situation. If
# it returns other than "", it will be a critical message.
# - perlexp_warn. The second one to be evaluated. If returns other than "", a
# warning will be issued to Nagios.
# - perlexp_default. If both of the above return "", it will be evaluated, and
# wathever returns this expression will be returned by the script. NOTE that
# this is different from the other two cases, to allow the user issue a
# warning or critical failure even if the other two don't return it.
#
# initial version: 28 Nov 2000 by Esteban Manchado Velázquez
# current status: 1.0
#
# History
# 19-Sep-2003	1.0	steveh@brendata.co.uk
#			Amended to utilise the RRDs supplied with rrdtool rather than the cricket code
#
# Required RRDs from rrdtool distribution be installed (install perl shared when building rrdtool).
#
# Copyright Notice: GPL
#

use strict;
use lib '/usr/local/nagios/libexec/' ;
use utils qw(%ERRORS &print_revision);
use RRDs;
use Getopt::Long;
&Getopt::Long::config('auto_abbrev');

my $PROGNAME="check_rrd.pl";

sub usage {
	print_revision($PROGNAME,'$Revision: 1.0 $ ');
	print "Nagios Plugin - Check rrd datafile\n";
	print "=" x 75,"\nERROR: Missing or wrong arguments!\n","=" x 75,"\n";
	print "check_rrd.pl --file=<file.rrd> --warning=<perl_exp_warn> --critical=<perl_exp_crit> --default=<perl_exp_default> [--dataset=<ds>] [--cf=<cf>] [--expire=<minutes>]\n\n";
	print "<perl_exp_*> is an expression that gets evaluated with \$_ at the current\n";
	print "value of the data source. If it returns something other than \"\", there\n";
	print "will be a warning or a critical failure. Else, the expression\n";
	print "<perl_exp_default> will be evaluated\n";
	print "<ds> is the number of the dataset that you wish to use\n";
	print "<cf> is one of MIN, MAX, AVERAGE or LAST\n";
	print "<minutes> the maximum time since last rrd update, otherwise WARNING. (5 mins assumed if not specified)\n";
	exit $ERRORS{'UNKNOWN'};	# Unknown
}

my $rrdfile;						# RRD file to open
my $cf;	#Function to apply
my $ds;	# Dataset to use
my @data;	# Special data reserved for the expressions, to pass data
# Perl expressions to evaluate
my $perl_exp_warn;
my $perl_exp_crit;
my $perl_exp_default;
my $expire;
my $debug;

# Evaluate Command Line Parameters
my $status = GetOptions(
                        "file=s",\$rrdfile,
                        "critical=s",\$perl_exp_crit,
                        "warning=s",\$perl_exp_warn,
                        "default=s",\$perl_exp_default,
                        "dataset=i",\$ds,
                        "expire=i",\$expire,
                        "cf=s",\$cf,
			"debug",\$debug
                        );

$ds =~ s/\$$//g if ($ds);		# Sometimes Nagios gives 1$ as the last parameter
$cf =~ s/\$$//g if($cf);		# Sometimes Nagios gives 1$ as the last parameter
$rrdfile =~ s/\$$//g if($rrdfile);	# Sometimes Nagios gives 1$ as the last parameter

$perl_exp_crit =~ s/\$$//g if($perl_exp_crit);		# Sometimes Nagios gives 1$ as the last parameter
$perl_exp_warn =~ s/\$$//g if($perl_exp_warn);		# Sometimes Nagios gives 1$ as the last parameter
$perl_exp_default =~ s/\$$//g if($perl_exp_default);		# Sometimes Nagios gives 1$ as the last parameter

usage() if ($status == 0 || ! ($rrdfile && $perl_exp_warn && $perl_exp_crit)); #  && $perl_exp_default)); 


	print $perl_exp_crit,"\n" if($debug);
	print $perl_exp_warn,"\n" if($debug);
	print $perl_exp_default,"\n" if($debug);
# Defaults
$ds=0 if(!($ds));
$cf="MAX" if(!($cf));
$expire=5*60 if(!($expire));

if (! $rrdfile) {
	print "Can't open data file for $rrdfile\n";	# Aaaargh!
	return $ERRORS{'UNKNOWN'};	# Unknown
}

if($expire!=0)
	{
	my ($last) = RRDs::last($rrdfile);
	printf("Now: %d Last: %d\n",time(),$last) if ($debug);
	my $now=time();
	if($now - $last > $expire*60)
		{
		printf("RRD data has not been updated within expiry interval. %d minutes since last update\n",($now-$last)/60);
		exit $ERRORS{'WARNING'};
		}

	}
my ($start,$step,$names,$data) = RRDs::fetch ($rrdfile,$cf);
my $ERR=RRDs::error;
if($ERR) {
	print "ERROR while fetching $rrdfile: $ERR\n"; # Ooops.....
	exit $ERRORS{'UNKNOWN'};      # Unknown
}

  my $line = @$data[$#data -1];
    my $value = @$line[$ds];

my $result;	# Result of the expressions (will be printed)

# First check for critical errors
$perl_exp_crit =~ /(.*)/;
$perl_exp_crit = $1;
	print $perl_exp_crit,"\n" if($debug);
$result = eval $perl_exp_crit;
if ($result) {
	print $result;
	print $perl_exp_crit,"\n" if($debug);
	exit 2;		# Critical
}

# Check for warnings
$perl_exp_warn =~ /(.*)/;
$perl_exp_warn = $1;
	print $perl_exp_warn,"\n" if($debug);
$result = eval $perl_exp_warn;
if ($result) {
	print $result;
	print $perl_exp_warn,"\n" if($debug);
	exit 1;		# Warning
}

$perl_exp_default =~ /(.*)/;
$perl_exp_default = $1;
	print $perl_exp_default,"\n" if($debug);
eval $perl_exp_default;	# Normally returns 0 (OK)