#!/usr/bin/perl -w
# nagios: -epn
#
####################### check_httpd_status.pl #######################
# Version : 1.3
# Date : 06 Aug 2010
#
# V1.3 Rewrite using Nagios::Plugin, rename check_httpd_status.pl (Stéphane Urbanovski)
# V1.2 Updated perf data to be PNP compliant, added proxy option (Gerhard Lausser)
# V1.1 Works with lighttpd server-status as well, added accesses perfdata
# V1.0 Inital Release
#
#
# Authors  : Dennis D. Spreen (dennis at spreendigital.de)
#				Based on check_apachestatus.pl v1.4 by 
#					De Bodt Lieven (Lieven dot DeBodt at gmail.com)
#						Updated by
#   						  Karsten Behrens (karsten at behrens dot in)
#		    				  Geoff McQueen (geoff dot mcqueen at hiivesystems dot com )
#				    		  Dave Steinberg (dave at redterror dot net)
#						Updated by
#							Gerhard Lausser (gerhard dot lausser at consol dot de)
# Licence : GPL - http://www.fsf.org/licenses/gpl.txt
#############################################################
#
#

use strict;
use warnings;
#use Data::Dumper;

use File::Basename;			# get basename()

use POSIX qw(setlocale);
use Locale::gettext;

sub load_module {
    my @names = @_;
    my $module;
    for my $name (@names) {
        my $file = $name;
        # requires need either a bare word or a file name
        $file =~ s{::}{/}gsxm;
        $file .= '.pm';
        eval {
            require $file;
            $name->import();
            $module = $name;
		};
		last if $module;
    }
    return $module;
}

my $plugin_module;
BEGIN {
	$plugin_module = load_module( 'Monitoring::Plugin', 'Nagios::Plugin' );
}
use LWP::UserAgent;
use HTTP::Status; # get status_message()
use Time::HiRes qw(gettimeofday tv_interval);
use Digest::MD5 qw(md5 md5_hex);


# Globals

my $VERSION = '1.3';
my $TIMEOUT = 10;
my $PROGNAME = basename($0);
# my $PROGNAME = 'check_httpd_status.pl';

# Retention files path (save previous values) :
# FIXME: Make this configurable
my $TempPath = '/tmp/';

# Check freshness og previous values
my $MaxUptimeDif = 60*30;  # Maximum uptime difference (seconds), default 30 minutes


# i18n :
setlocale(LC_MESSAGES, '');
textdomain('nagios-plugins-perl');

# Translate Apache / lighthttpd scoreboard status
my %TranslationTable = (
	'APACHE' => {
		'.' => 'OpenSLot',
		'_' => 'Waiting',
		'I' => 'Idle',
		'S' => 'Starting',
		'R' => 'Reading',
		'W' => 'Sending',
		'K' => 'Keepalive',
		'D' => 'DNS',
		'C' => 'Closing',
		'L' => 'Logging',
		'G' => 'Finishing',
	},
	'LIGHTTPD' => {
		'.' => 'Connect',
		'C' => 'Close',
		'E' => 'HardError',
		'r' => 'Read',
		'R' => 'ReadPost',
		'W' => 'Write',
		'h' => 'HandleRequest',
		'q' => 'RequestStart',
		'Q' => 'ReqestEnd',
		's' => 'ResponseStart',
		'S' => 'ResponseEnd',
	},
);


my $np = $plugin_module->new(
	version => $VERSION,
	blurb => _gt('Apache / Lighthttpd server status monitor for Nagios'),
	usage => "Usage: %s [ -H <host> [-p <port>] [-t <timeout>] [-w <warn_level> -c <crit_level>] [-V] [-u <url>] [-U user -P pass -r realm]",
	extra => &showExtra(),
	timeout => $TIMEOUT+1
);

$np->add_arg (
	spec => 'hostname|H=s',
	help => _gt('Name or IP address of host to check'),
	required => 1,
);

$np->add_arg (
	spec => 'port|p=i',
	help => _gt('Http port'),
);
$np->add_arg (
	spec => 'url|u=s',
	help => _gt('Specific URL to use, instead of the default http://<hostname>/server-status?auto'),
	default => '/server-status?auto',
);

$np->add_arg (
	spec => 'user|U=s',
	help => _gt('Username for basic auth'),
);
$np->add_arg (
	spec => 'pass|P=s',
	help => _gt('Password for basic auth'),
);
$np->add_arg (
	spec => 'realm|r=s',
	help => _gt('Realm for basic auth'),
);
$np->add_arg (
	spec => 'proxy|X=s',
	help => _gt('Proxy-URL for http and https (mandatory)'),
);

$np->add_arg (
	spec => 'warn|w=s',
	help => _gt('Number of available slots that will cause a warning (Range format).'),
);
$np->add_arg (
	spec => 'crit|c=s',
	help => _gt('Number of available slots that will cause an error (Range format).'),
);


$np->getopts;

my $o_host = $np->opts->get('hostname');
my $o_port = $np->opts->get('port');
my $o_url = $np->opts->get('url');
my $o_user = $np->opts->get('user');
my $o_pass = $np->opts->get('pass');
my $o_realm = $np->opts->get('realm');
my $o_proxy = $np->opts->get('proxy');
my $o_warn_level = $np->opts->get('warn');
my $o_crit_level = $np->opts->get('crit');

# if (((defined($o_warn_level) && !defined($o_crit_level)) || 
# 	(!defined($o_warn_level) && defined($o_crit_level))) || 
# 	((defined($o_warn_level) && defined($o_crit_level)) && (($o_warn_level != -1) &&  ($o_warn_level <= $o_crit_level)))
# 	) {
# 	$np->nagios_exit(UNKNOWN, _gt("Check warn and crit!") );
# }

my $o_proto = 'http';
my $url = undef;
my $httpserver = 'APACHE'; #assume it is apache by default

if (($o_url =~ m/^http(s?)\:\/\//i) ){
	$url = $o_url;
	if ($1 eq 's') {
		$o_proto = 'https';
	}
} else {
	$url = $o_proto.'://' . $o_host;
	if ( defined($o_port)) {
		$url .= ':' . $o_port;
	}
	if ( $o_url !~ /^\// ) {
		$url .= '/';
	}
	$url .= $o_url;
}

if ( $url !~ /\?auto$/ ) {
	$url .= '/server-status?auto';
}

my $ua = LWP::UserAgent->new( protocols_allowed => ['http', 'https'], timeout => $TIMEOUT);
$ua->agent($PROGNAME.'-'.$VERSION);


logD("Web URL : $url");

my $req = HTTP::Request->new( GET => $url );
if ( defined($o_realm) ) {
    if ( ! defined($o_port) ) {
        $o_port = 80;
    }
    $ua->credentials("$o_host:$o_port", $o_realm, $o_user, $o_pass);
}
elsif ( defined($o_user) ) {
	$req->authorization_basic($o_user, $o_pass);
}

if ( defined($o_proxy) ) {
	if ($o_proto eq 'https') {
		if ($o_proxy =~ /^http:\/\/(.*?)\/?$/) {
			$o_proxy = $1;
		}
		$ENV{HTTPS_PROXY} = $o_proxy;
	} else {
		$ua->proxy(['http'], $o_proxy);
	}
}

my $timing0 = [gettimeofday];
my $response = $ua->request($req);
my $timeelapsed = tv_interval($timing0, [gettimeofday]);


if ( $response->is_error() ) {
	my $err = $response->code." ".status_message($response->code)." (".$response->message.")";
	my $status = CRITICAL;
	$np->add_message(CRITICAL,  );

	if (defined($o_warn_level) || defined($o_crit_level)) {
		$status = UNKNOWN;
	}
	$np->nagios_exit($status, _gt("HTTP error: ").$err );

} elsif ( ! $response->is_success() ) {
	my $err = $response->code." ".status_message($response->code)." (".$response->message.")";
	$np->add_message(CRITICAL, _gt("Internal error: ").$err );
}



my $webcontent = $response->content;

logD("Web content :\n----------------------------\n".$webcontent."\n----------------------------");

my $patternFound = 0;

my $Uptime = 0;
if ( $webcontent =~ m/Uptime: (\d*?)\n/) {
	$Uptime = $1;
	$patternFound++;
}
	
my $TotalAccesses = 0;
if ( $webcontent =~ m/Total Accesses: (.*?)\n/) {
	$TotalAccesses = $1;
	$patternFound++;
} else {
	$np->add_message(WARNING, _gt('"Total Accesses" not set ! (need extented status ?)') );
}

my $TotalKbytes = 0;
if ( $webcontent =~ m/Total kBytes: (.*?)\n/) {
	$TotalKbytes = $1;
	$patternFound++;
}

my $ScoreBoard = '';
if ( $webcontent =~ m/Scoreboard: (.*?)\n/) {
	$ScoreBoard = $1;
	$patternFound++;
} else {
	$np->add_message(WARNING, _gt("Scoreboard not found in reponse !") );
}

my $BusyWorkers = 0;
if ( $webcontent =~ m/(BusyWorkers|BusyServers): (.*?)\n/) {
	$BusyWorkers = $2;
	$patternFound++;
	if ($1 eq 'BusyServers') {
		$httpserver = 'LIGHTTPD';
	}
}

my $IdleWorkers = 0;
if ( $webcontent =~ m/(IdleWorkers|IdleServers): (.*?)\n/) {
	$IdleWorkers = $2;
	$patternFound++;
}

if ( $patternFound <= 1) {
	$np->nagios_exit(CRITICAL, _gt("Server-status informations not found !") );
}

	
my $TempFile = $TempPath.$o_host.'_check_httpd_status'.md5_hex($url);

my $LastUptime = 0;
my $LastTotalAccesses = 0;
my $LastTotalKbytes = 0;

if ((-e $TempFile) && (-r $TempFile) && (-w $TempFile)) {
	if ( !open (RETENTION_FILE, '<',$TempFile) ) {
		$np->nagios_exit(CRITICAL, sprintf(_gt('Error while trying to read %s !'),$TempFile) );
	}
	$LastUptime = <RETENTION_FILE>;
	$LastTotalAccesses = <RETENTION_FILE>;
	$LastTotalKbytes = <RETENTION_FILE>;
	close (RETENTION_FILE);
	chomp($LastUptime);
	chomp($LastTotalAccesses);
	chomp($LastTotalKbytes);
	logD("LastUptime=$LastUptime LastTotalAccesses=$LastTotalAccesses LastTotalKbytes=$LastTotalKbytes (from $TempFile)");
	
} else {
	logD("Retention file '$TempFile' not found");
}

if ( !open (RETENTION_FILE, '>',$TempFile) ) {
	$np->nagios_exit(CRITICAL, sprintf(_gt('Error while trying to write to %s !'),$TempFile) );
}
print RETENTION_FILE "$Uptime\n"; 
print RETENTION_FILE "$TotalAccesses\n"; 
print RETENTION_FILE "$TotalKbytes\n";
close (RETENTION_FILE);
	
my $ReqPerSec = 0;
my $BytesPerReq = 0;
my $BytesPerSec = 0;

my $DiffTime = $Uptime-$LastUptime;

if ( ($DiffTime > 0) && ($DiffTime < $MaxUptimeDif) && ($TotalAccesses >= $LastTotalAccesses) && ($TotalKbytes >= $LastTotalKbytes) ) {

	$ReqPerSec = ($TotalAccesses-$LastTotalAccesses)/$DiffTime;
	$np->add_perfdata(
		'label' => 'ReqPerSec',
		'value' => sprintf('%.3f',$ReqPerSec),
		'uom' => 'req/s',
	);
	
	$BytesPerSec = (($TotalKbytes-$LastTotalKbytes)*1024)/$DiffTime;
	$np->add_perfdata(
		'label' => 'BytesPerSec',
		'value' => sprintf('%.2f',$BytesPerSec),
		'uom' => 'B/s',
	);
	
	my $Accesses = ($TotalAccesses-$LastTotalAccesses);
	
	if ( $Accesses > 0 ) {
		$BytesPerReq = (($TotalKbytes-$LastTotalKbytes)*1024)/$Accesses;
		$np->add_perfdata(
			'label' => 'BytesPerReq',
			'value' => sprintf('%.2f',$BytesPerReq),
			'uom' => 'B/req',
		);
	}
}
	
my $CountOpenSlots = ($ScoreBoard =~ tr/\.//);
my $TotalSlots = $CountOpenSlots+$IdleWorkers+$BusyWorkers;
my $InfoData = '';

my %WorkerStates = ();

map( $WorkerStates{$_}++ , split(//,$ScoreBoard) );


foreach my $slotState ( sort(keys(%{$TranslationTable{$httpserver}})) ) {
	my $val = 0 ;
	if ( defined($WorkerStates{$slotState}) ) {
		$val = $WorkerStates{$slotState};
	}

	$np->add_perfdata(
		'label' => $TranslationTable{$httpserver}{$slotState},
		'value' => $val,
	);
}


if ( $httpserver eq 'APACHE' ) {
	$InfoData = sprintf ("%.3f s - %d/%d Busy/Idle, %d/%d Open/Total, %.1f requests/s, %.1f B/s, %d B/request", 
		$timeelapsed, $BusyWorkers, $IdleWorkers, $CountOpenSlots, $TotalSlots, $ReqPerSec, $BytesPerSec, $BytesPerReq);
	
} else {
	$InfoData = sprintf ("%.3f sec. response time, Busy/Idle %d/%d, slots %d, ReqPerSec %.1f, BytesPerReq %d, BytesPerSec %d",
		$timeelapsed, $BusyWorkers, $IdleWorkers, $TotalSlots, $ReqPerSec, $BytesPerReq, $BytesPerSec);

}

$np->add_message(OK, $InfoData);


my $fw = $CountOpenSlots + $IdleWorkers;

logD("FreeWorker = ".$fw);

my $tmp_status = $np->check_threshold(
	check => $fw,
	warning => $o_warn_level,
	critical => $o_crit_level,
);
	
$np->add_perfdata(
	'label' => 'FreeWorker',
	'value' => $fw,
	'min' => 0,
	'threshold' => $np->threshold()
);

if ( $tmp_status ) {
	$np->add_message($tmp_status, sprintf(_gt(" Not enough free worker (%d) !"),$fw) );
}
	


my ($status, $message) = $np->check_messages('join' => ' ');
$np->nagios_exit($status, $message );


sub logD {
	print STDERR 'DEBUG:   '.$_[0]."\n" if ($np->opts->verbose);
}
sub logW {
	print STDERR 'WARNING: '.$_[0]."\n" if ($np->opts->verbose);
}
# Gettext wrapper
sub _gt {
	return gettext($_[0]);
}
sub showExtra {
	return <<EOT;
(c)2009 Dennis D. Spreen
(c)2010 Stéphane Urbanovski

Note :

  This plugin check Apache or Lighthttpd server-status page (using mod_status). It require the ?auto option.

  Warning and critical values follow Nagios::Plugins::Threshold format. See http://nagiosplug.sourceforge.net/developer-guidelines.html

  Example (note the trailing colon):

  check_httpd_status -H www.server.org -w 100: -c 10:
        Warn if less than 100 workers are available
        Crit if less than 10 workers are available
EOT
}