#!/usr/bin/perl

################################################################################
################################################################################
##                                                                            ##
##  check_mod_jk_status                                                       ##
##  Copyright © 2014 Christian ter Stein, Hochschule Niederrhein - University ##
##  of Applied Sciences                                                       ##  
##                                                                            ##
##  Check the status of mod_jk load balancers by analysis of jkmanager's      ##
##  XML page from status                                                      ## 
##                                                                            ##
##  This program is free software; you can redistribute it and/or modify      ##
##  it under the terms of the GNU General Public License as published by      ## 
##  the Free Software Foundation; either version 3 of the License, or         ## 
##  (at your option) any later version.                                       ## 
##                                                                            ##
##  This program is distributed in the hope that it will be useful,           ##
##  but WITHOUT ANY WARRANTY; without even the implied warranty of            ##
##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              ## 
##  GNU General Public License for more details.                              ##
##                                                                            ##
##  You should have received a copy of the GNU General Public License         ## 
##  along with this program. If not, see <http://www.gnu.org/licenses/>.      ##
##                                                                            ##
##                                                                            ##
##      ******************                                                    ##
##      * Requires       *                                                    ## 
##      ******************                                                    ##
##      *                *                                                    ##
##      * Perl Modules:  *                                                    ##
##      * -------------  *                                                    ##
##      * XML::Simple    *                                                    ##
##      * LWP::Simple    *                                                    ##
##      *                *                                                    ##
##      ******************                                                    ## 
##                                                                            ##
##                                                                            ## 
##      ***************************************************************       ##
##      * Configuration                                               *       ##
##      ***************************************************************       ##
##      *                                                             *       ##
##      * Set Server vars:                                            *       ##
##      * ----------------                                            *       ##
##      * #If jkmanager is protected                                  *       ##
##      * my $username = 'user';                                      *       ##
##      * my $pass = 'pass';                                          *       ##
##      * #Location of jkmanager                                      *       ##
##      * my $domain = 'domain.com/jkmanager';                        *       ##
##      * my $server_ip = $username.":".$pass."@".$domain;            *       ##
##      * my $balancer  = 'mybalancer';                               *       ##
##      *                                                             *       ##
##      * # Balancer properties to monitor                            *       ## 
##      * my @member_data = ("activation", "route","state","host");   *       ##
##      * #If you change the member_data list, make sure that checks  *       ##
##      * #in sub ParseXML() also changed                             *       ##
##      *                                                             *       ##
##      ***************************************************************       ##
##                                                                            ##
##      v1 17/09/2014                                                         ##
##                                                                            ##
################################################################################                                                                          
################################################################################

use strict;
use warnings;
use XML::Simple;
use LWP::Simple;

####################################################
#  Custom vars for monitoring                      #
####################################################

## Server  vars
my $username = 'user';
my $pass = 'pass';
my $domain = 'domain.com/jkmanager';
my $server_ip = $username.":".$pass."@".$domain;
my $balancer  = 'mybalancer';

# Balancer properties to monitor
my @member_data = ("activation", "route","state","host");

#Regex to check whether unauthorized person has changed host and route
my $route_exp = qr/my_server_name_0[0-9]/;  #e.g. qr/myserver[0-9]/
my $host_exp = qr/127.0.0.[0-9]/;      #e.g. qr/127.0.0.[0-9]/;


####################################################
#  Main Application                                #
####################################################

#Global vars
my $state_code = 0;
my $state_message = "";
my $message = "";

## Fetch the status
my $xml = GetXML($server_ip);

## Parse the XML and generate status message
ParseXML($xml);

## Print status message
SendStatus();


###################################################
#  Subs                                           #
###################################################

## Fetch the XML from management address
sub GetXML
{
    ### Get the XML page 
    my $ip = shift;
    my $url = "https://$ip?mime=xml";
    my $page = get $url;
    die "Couldn't get $url" unless defined $page;
    ## Return the XML
    return $page;
}

## Parse the XML and return the results
sub ParseXML
{
    ### Get XML to parse
    my $xml = shift;
    my $status = XMLin($xml);
    my %members;
  
## Exit if specified balancer wasn't found
    PrintException ("Supplied balancer wasn't found!") unless defined ( $status->{'jk:balancers'}->{'jk:balancer'} );
    
    ## Get members count
    my $member_count = $status->{'jk:balancers'}->{'jk:balancer'}{'member_count'};
    
    ## Get member data
    foreach my $member ( sort keys %{$status->{'jk:balancers'}->{'jk:balancer'}->{'jk:member'}} )
    {
      
        foreach (@member_data) {
	    $members{$member}{$_} = $status->{'jk:balancers'}->{'jk:balancer'}->{'jk:member'}->{$member}{$_};
	}
    }


##Check Members
  foreach my $m ( keys %members ) {
    $state_message = "";
    for my $attribute ( keys %{ $members{$m} } ) {
	# check attribute activation
        if($attribute eq "activation") {
	    my $activation = $members{$m}{$attribute};
	    if($activation eq "DIS") {
	        if($state_code != 2) {
		    $state_code = 1;
		}
		$state_message .= "$attribute = $activation, ";
	    }
	    if($activation eq "STP") {
                $state_code = 2;
		$state_message .= "$attribute = $activation, ";
            }
	} 
	# check attribute state
	if($attribute eq "state") {
	    my $state = substr($members{$m}{$attribute},0,2);
	    if($state eq "BUSY") {
                if($state_code != 2) {
		    $state_code = 1;
		}
		$state_message .= "$attribute = $state, ";
            }
	    if($state eq "REC") {
                if($state_code != 2) {
                    $state_code = 1;
                }
	        $state_message .= "$attribute = $state, ";
            }
	    if($state eq "PRB") {
		if($state_code != 2) {
                    $state_code = 1;
                }
		$state_message .= "$attribute = $state, ";
            }
	    if($state eq "FRC") {
	        if($state_code != 2) {
                    $state_code = 1;
                }
		$state_message .= "$attribute = $state, ";
            }
	    if($state eq "ERR") {
                $state_code = 2;
	 	$state_message .= "$attribute = $state, ";
            }
	}
	# check attribute route
	if($attribute eq "route") {
	    my $route = $members{$m}{$attribute};
	    unless($route  =~  m/$route_exp/) {
		$state_code = 2;
	        $state_message .= "$attribute = $route, ";
	    }
	}
	# check attribute host
	if($attribute eq "host") {
            my $host = $members{$m}{$attribute};
	    unless($host  =~ m/$host_exp/) {
	        $state_code = 2;
                $state_message .= "$attribute = $host, ";
            }
        }
    }
    ## generate status message
    if($state_message ne "") {
        $message .= " +++ $m: $state_message ";
    }
    elsif($message eq "") {   
         $message = "All Balancer Members OK";
    }
  }	
}

sub SendStatus
{
    print $message;
    print "\n";
    exit $state_code;
}

sub PrintException
{
    my $msg = shift;
    print "$msg\n";
    exit 1;
}