#!/usr/bin/perl
# -*- perl -*-
#
# Plugin to graph http performance
# Version: 0.8.7
#
# The purpose of this plugin is to monitor several properties of a web page.
# All measurements are done for the complete web page, including images, css
# and other content a standard browser would download automatically.
#
# This version supports monitoring:
#   * The total time to download a complete web page (using serial GET requests)
#   * The total size of a web page
#   * The different response codes (200, 404, 500, etc)
#   * The different tags (img src, a href, etc)
#   * The the different content types (image/png, text/css/, etc)
#   * The number of elements the web page consists of
# 
# Author:  Espen Braastad / Linpro AS
#          espen@linpro.no
#
##### Short usage guide: #####
#
# Requirements:
#  * The server running this plugin must be allowed  to connect to the web 
#    server(s) you are going to monitor.
#  * Some perl modules: 
#    Time::HiRes, LWP::UserAgent, HTML::LinkExtor, LWP::ConnCache
#
# Initial configuration:
#  1. Copy this file to /usr/share/munin/plugins/
#
#  2. Create a file (/etc/munin/http_load_urls.txt) with one
#     full url per line, as many as you want, i.e.:
#      $ echo "http://www.dn.no/" >> /etc/munin/urls.txt
#      $ echo "http://www.intrafish.no/" >> /etc/munin/urls.txt
#
#  3. Add a cron job running the plugin with cron as the argument:
#     */15 * * * * <user> /usr/sbin/munin-run http_load_<site>_loadtime cron
#     <user> should be the user that has write permission to the $cachedir
#     directory set below. <site> should be any of the configured sites (all
#     sites will get updated), likewise, you should replace loadtime by any
#     metric that is enabled for that site (all metrics will get updated).
#     Set the intervals to whatever you want.
#
#     For verbose output (for debugging) you can do:
#     sudo -u <user> /usr/share/munin/plugins/http_load_ cron verbose
#
#  4. Run munin-node-configure --suggest --shell and run the symlink
#     commands manually to update the munin-node plugin list.
#  
# (5. If you want to change the filter which the plugin uses to select which
#     tags to follow in a web page, edit the subroutine called "filter" below.)
#
# Add a new url to monitor:
#  1. Add a new line in /etc/munin/urls.txt with the full URL, i.e.:
#      $ echo "http://www.linpro.no/" >> /etc/munin/http_load_urls.txt
#
#  2. Run munin-node-configure --suggest --shell and manually
#     add the new symlink(s)
#
#  3. /etc/init.d/munin-node restart
#
# Remove a url from monitoring:
#  1. Remove it from /etc/munin/http_load_urls.txt
#
#  2. Remove ${cachedir}/http_load_<url_id>*
#
#  3. Remove /etc/munin/plugins/http_load_<url_id>*
#
#  4. /etc/init.d/munin-node restart
#
#####
#
# Todo:
#   * Add support for forking to simulate real browsers
#   * Use checksums as fieldnames
#
# $Id: $
#
# Magic markers:
#%# family=auto
#%# capabilities=autoconf suggest

use strict;
use Time::HiRes qw( gettimeofday tv_interval );
use LWP::UserAgent;
use HTML::LinkExtor;
use LWP::ConnCache;

my $url_file="/etc/munin/http_load_urls.txt";
my $cachedir=$ENV{MUNIN_PLUGSTATE};

my $debug=$ENV{MUNIN_DEBUG};
my $timeout=10;
my $max_redirects=10;
my $scriptname="http_load_";
my $useragent="Mozilla/5.0 (Munin; $scriptname)";

# Function to read the $url_file and return the contents in a hash
sub read_urls{
	my $file=$_[0];
	my %urls=();
	if(-r $file){
		open(FILE,'<'.$file);
		while (<FILE>) { 
			my $url=$_;
			chomp($url);
			my $id=get_id($url);
			if(length($id)>0){
				$urls{$id}=$url;
			}
		}
		close (FILE);
	}
	return %urls;
}

# Function to read cache, return a hash
sub read_cache{
	my $file=$_[0];
	my %cache=();
	if(-r $file){
		open(FILE,'<'.$file);
		while (<FILE>) { 
			m/^(\S*)\s+(.*)$/;
			$cache{ $1 } = $2;
		}
		close (FILE);
	}
	return %cache;
}

# Function to filter the html tags, which files do we want to download
sub filter{
	my $tag=$_[0];
	my $status=1;

	# Some example data:
	# link href http://www.intrafish.no/template/include/css/intrafish.css
	# script src http://www.intrafish.no/template/include/js/intrafish.js
	# a href http://adserver.adtech.de/?adlink%7C2.0%7C405%7C119488%7C1%7C16%7CADTECH;grp=8491;loc=300;
	# img src http://adserver.adtech.de/?adserv%7C2.0%7C405%7C119488%7C1%7C16%7CADTECH;grp=8491;
	# area href http://go.vg.no/cgi-bin/go.cgi/sol/http://www.sol.no/sgo/vg/http://www.sol.no/underholdning/humor/?partnerid=vg

	# status=1 => do download (default)
	# status=0 => do not download

	if("$tag" eq "form action"){
		$status=0;
	}
	if("$tag" eq "a href"){
		$status=0;
	}
	if("$tag" eq "area href"){
		$status=0;
	}
	return $status;
}

# Return the cache file name for this plugin
sub get_cache_file_name{
	my $scriptname=$_[0];
	my $id=$_[1];
	my $file="";

	$file = $scriptname . $id . ".cache";
	$debug && print "Cache file: " . $file . "\n";

	return $file;
}

# Get fieldname (making sure it is munin-1.0 "compatible" as a fieldname)
# 1. Remove all non-word characters from a string)
# 2. Make sure it has maximum 19 characters
#    2.1 If not, truncate the host part, while keeping anything after an underscore (e.g., HTTP response status)
sub get_fieldname{
	my $url=$_[0];
	$url =~ s/\W//g;
	if(length($url) > 19){
		$url =~ s/(\S+)_(\S+)/ /g;
		my $host = $1;
		my $info = $2;
		my $suffixlength = length($info) + 1;
		if ($suffixlength > 1) {
			$url = substr($host, 0, 19 - $suffixlength) . '_' . $info;
		} else {
			$url = substr($url, 0, 19);
		}
	}
	return $url;
}

# Same as get_fieldname except it doesn't substr
sub get_id{
	my $url=$_[0];
	$url =~ s/[\W_]//g;
	return $url;
}

$debug && print "Scriptname: " . $scriptname . "\n";

# Get the url id and the type of the graph
#
# The filename format is http_load_X_Y where
# X: The line number in urls.txt
# Y: The type of graph (elements, size, loadtime, ..)

my ($id,$type);
$0 =~ /http_load(?:_([^_]+)|)_(.+)\s*$/;
$id  = $1;
$type = $2;

$debug && print "Id: $id, Type: $type\n";

if($ARGV[0] and $ARGV[0] eq "autoconf") {
	my %urls=&read_urls($url_file);
	if(keys(%urls) gt 0){
		print "yes\n";
		exit(0);
	} else {
		print "no\n";
		exit(1);
	}

} elsif($ARGV[0] and $ARGV[0] eq "suggest") {
	# get the url list, print suggestions for usage
	my %urls=&read_urls($url_file);
	while ( my ($id, $url) = each(%urls) ) {
        	$debug && print "id: $id => url: $url\n";
        	print $id . "_size\n";
        	print $id . "_loadtime\n";
        	print $id . "_response\n";
        	print $id . "_tags\n";
        	print $id . "_type\n";
        	print $id . "_elements\n";
    	}
	exit(0);

} elsif($ARGV[0] and $ARGV[0] eq "cron") {
	# This thing is run by cron and should write a cache file for munin-node to 
	# read from

	my $verbose=0;
	if(
		$ENV{MUNIN_DEBUG} eq "1" or
		$ARGV[1] and $ARGV[1] eq "verbose"
	) {
		$verbose=1;
		print "Verbose output\n";
	}

	my %urls=&read_urls($url_file);
	my %output;
	my %res;
	my $t0;
	my ($request,$response,$status,$link,$contents,$page_parser,$cachefile);

	while ( my ($id, $url) = each(%urls) ) {
        	$verbose && print "Fetching $url (id: $id)... \n";
		
		$t0=0;
		$status=0;
		%output=();
		my $host="";
		if($url =~ m/\w+\:\/\/([^\/]+).*/){
			$host=$1;
        		$verbose && print " Host: $host\n";
		}

		$output{"url"}=$url;
		$output{"timestamp"}=time();
        	$verbose && print " Timestamp: " . $output{"timestamp"} . "\n";

	        my $browser = LWP::UserAgent->new();

		$browser->agent($useragent);
	        $browser->timeout(${timeout});
		$browser->max_redirect( $max_redirects );
		$browser->conn_cache(LWP::ConnCache->new());

		$response = $browser->get($url);

		# Calculating time from now:
		$t0 = [gettimeofday];
	        if ($response->is_success()) {
	                $status=1;
			$output{"elements_" . $host}+=1;
	        }

        	$contents = $response->content();
	        $output{"loadtime_" . $host} += sprintf("%.6f",tv_interval ( $t0, [gettimeofday]));
        	$output{"size_" . $host}+=length($contents);
		$output{"response_" . $host . "_" . $response->code}+=1;
		$output{"type_" . $response->content_type}+=1;

	        $page_parser = HTML::LinkExtor->new(undef, $url);
	        $page_parser->parse($contents)->eof;
	        my @links = $page_parser->links;
        	$verbose && print " Processing links:\n";

        	%res=();
	        foreach $link (@links){
			my $tag=$$link[0] . " " . $$link[1];
			
			$output{"tags_" . $$link[0] . "-" . $$link[1]}+=1;
	
			if(filter($tag)){
				$verbose && print "  Processing: " . $$link[0] . " " . $$link[1] . " " . $$link[2] . "\n";

				# Extract the hostname and add it to the hash
				if($$link[2] =~ m/https?\:\/\/([^\/]+).*/){
					$host=$1;
					$output{"elements_" . $host}+=1;
				}

                	        my $suburl=$$link[2];
	
				$t0 = [gettimeofday];
				$response = $browser->get($suburl);
	        		$output{"loadtime_" . $host} += sprintf("%.6f",tv_interval ( $t0, [gettimeofday]));

        			$contents = $response->content();
        			$output{"size_" . $host}+=length($contents);
				$output{"response_" . $host . "_" . $response->code}+=1;
				$output{"type_" . $response->content_type}+=1;

				$verbose && print "              Response: " . $response->code . " Size: " . length($contents) . "\n";
			} else {
				$verbose && print "  Skipping:   " . $$link[0] . " " . $$link[1] . " " . $$link[2] . "\n";
			}
		}

		$cachefile=$cachedir . "/" . &get_cache_file_name($scriptname,$id);
		$debug && print "Reading cache file: " . $cachefile . "... ";

		my %input=read_cache($cachefile);

		$debug && print "done\n";

		# Resetting all values to 0 before adding new values
		while ( my ($id, $value) = each(%input) ) {
			$input{$id}="U";
    		}
		
		# Adding new values
		while ( my ($id, $value) = each(%output) ) {
			$input{$id}=$value;
        		$verbose && print " Result: " . $id . " -> " . $value . "\n";
    		}
		
		# Writing the cache
		$verbose && print "Writing cache file: " . $cachefile . "... ";
		open(FILE,">".$cachefile);
		while ( my ($id, $value) = each(%input) ) {
			print FILE $id . " " . $value . "\n";
		}
		close(FILE);
		$verbose && print "done\n";
	}
	exit(0);
}elsif($ARGV[0] and $ARGV[0] eq "config") {
	my %urls=&read_urls($url_file);
	
        print "graph_title $urls{$id} ${type}\n";
        print "graph_args -l 0 --base 1000\n";
        print "graph_category webserver\n";
	$debug && print "Reading cache file\n";
	my $cachefile=$cachedir . "/" . &get_cache_file_name($scriptname,$id);
	my %cache=read_cache($cachefile);

	my $count=0;
	$debug && print "The cache file contains " . keys(%cache) . " lines\n";

	if($type eq "size"){
                print "graph_vlabel Bytes\n";
		print "graph_total Total\n";
         	print "graph_info This graph is generated by a set of serial GETs to calculate the total size of $urls{$id}.\n";

		if(keys(%cache)>0){
			for my $key ( sort reverse keys %cache ){
				my $value=$cache{$key};
				
				if($key =~ m/^size_(\S+)$/){
					my $host=$1;
					my $value=$value;

					my $name=$1;
					$name=get_fieldname($name);
	
        	        		print "$name.label from $host\n";
        	        		print "$name.min 0\n";
        	        		print "$name.max 20000000\n";
					if($count eq 0){
						print "$name.draw AREA\n";
					} else {
						print "$name.draw STACK\n";
					}
					$count+=1;
				}
			}
		}
	}elsif($type eq "loadtime"){
                print "graph_vlabel Seconds\n";
		print "graph_total Total\n";
         	print "graph_info This graph is generated by a set of serial GETs to calculate the total time to load $urls{$id}. ";
		print "Note that browsers usually fork() the GET requests, resulting in a shorter total loading time.\n";
		
		if(keys(%cache)>0){
			for my $key ( sort reverse keys %cache ){
				my $value=$cache{$key};

				if($key =~ m/^loadtime_(\S+)$/){
					my $host=$1;
					my $value=$value;

					my $name=$1;
					$name=get_fieldname($name);
	
        	        		print "$name.label from $host\n";
        	        		print "$name.min 0\n";
        	        		print "$name.max 400\n";
					if($count eq 0){
						print "$name.draw AREA\n";
					} else {
						print "$name.draw STACK\n";
					}
					$count+=1;
				}
			}
		}

	}elsif($type eq "elements"){
                print "graph_vlabel Number of elements\n";
		print "graph_total Total\n";
        	print "graph_info This graph is generated by a set of serial GETs to count the number of elements (images, CSS files, etc) from $urls{$id}.\n";
	
		if(keys(%cache)>0){
			for my $key ( sort reverse keys %cache ){
				my $value=$cache{$key};
       
				if($key =~ m/^elements_(\S+)$/){
					my $host=$1;
					my $value=$value;

					my $name=$1;
					$name=get_fieldname($name);
	
        	        		print "$name.label from $host\n";
        	        		print "$name.min 0\n";
        	        		print "$name.max 10000\n";
					if($count eq 0){
						print "$name.draw AREA\n";
					} else {
						print "$name.draw STACK\n";
					}
					$count+=1;
				}
			}
		}
	}elsif($type eq "response"){
                print "graph_vlabel Server response code count\n";
		print "graph_total Total\n";
         	print "graph_info This graph is generated by a set of serial GETs to visualize the server response codes received while loading $urls{$id}.\n";

		if(keys(%cache)>0){
			for my $key ( sort reverse keys %cache ){
				my $value=$cache{$key};

				if($key =~ m/^response_(\S+)$/){
					my $host=$1;
					my $value=$value;

					my $name=$1;
					$name=get_fieldname($name);

					$host =~ s/\_/ /g;
					$host =~ s/(\S+)\s(\d+)/ /g;
					$host=$1;
					my $code=$2;
	
        	        		print "$name.label $host ($code)\n";
        	        		print "$name.min 0\n";
        	        		print "$name.max 10000\n";
					if($count eq 0){
						print "$name.draw AREA\n";
					} else {
						print "$name.draw STACK\n";
					}
					$count+=1;
				}
			}
		}
	}elsif($type eq "type"){
                print "graph_vlabel Content type count\n";
		print "graph_total Total\n";
         	print "graph_info This graph is generated by a set of serial GETs to visualize the different content types $urls{$id} consists of.\n";

		if(keys(%cache)>0){
			for my $key ( sort reverse keys %cache ){
				my $value=$cache{$key};

				if($key =~ m/^type_(\S+)$/){
					my $type=$1;
					my $value=$value;

					my $name=$1;
					$name=get_fieldname($name);

					#$host =~ s/\_/ /g;
					#$host =~ s/(\S+)\s(\S+)/ /g;
					#$host=$1;
					#my $type=$2;
	
        	        		print "$name.label $type\n";
        	        		print "$name.min 0\n";
        	        		print "$name.max 100000\n";
					if($count eq 0){
						print "$name.draw AREA\n";
					} else {
						print "$name.draw STACK\n";
					}
					$count+=1;
				}
			}
		}
	}elsif($type eq "tags"){
                print "graph_vlabel HTML tag count\n";
		print "graph_total Total\n";
         	print "graph_info This graph is generated by a set of serial GETs to visualize the different tags $urls{$id} consists of.\n";

		if(keys(%cache)>0){
			for my $key ( sort reverse keys %cache ){
				my $value=$cache{$key};

				if($key =~ m/^tags_(\S+)$/){
					my $host=$1;
					my $value=$value;

					my $name=$1;
					$name=get_fieldname($name);

					$host =~ s/\W/ /g;
	
        	        		print "$name.label $host\n";
        	        		print "$name.min 0\n";
        	        		print "$name.max 100000\n";
					if($count eq 0){
						print "$name.draw AREA\n";
					} else {
						print "$name.draw STACK\n";
					}
					$count+=1;
				}
			}
		}
	}
	exit(0); 
} else {
	my $cachefile=$cachedir . "/" . &get_cache_file_name($scriptname,$id);
	$debug && print "Reading cache file: " . $cachefile . "\n";
	my %cache=read_cache($cachefile);
	$debug && print "Number of lines in cache file: " . keys(%cache) . "\n";

	if(keys(%cache)>0){
		for my $key ( sort keys %cache ){
			my $value=$cache{$key};
			if($key =~ m/^([A-Za-z]+)\_(\S+)$/){
				my $name=$2;
				
				if ($1 eq $type){
					$name=get_fieldname($name);
					print $name . ".value " . $value . "\n";
				}
			} elsif(m/^(\S+)\s+(\S+)$/){
				if ($1 eq $type){
					print $1 . ".value " . $2 . "\n";
				}
			}
		}
	}
} 

# vim:syntax=perl