#!/usr/bin/perl

=head1 INSTALLATION

This plugin requires data from apache. You can get at the data in two ways:

1) Install the pipelogger (logs without using disk space, ram only, highly performant)
  - Install /usr/share/munin/apache_pipelogger as executable for apache/wwwrun
  - Install logger to httpd.conf

    # Log vhost port method response_bytes response_time_ms httpd_status
    <IfModule mod_log_config.c>
      CustomLog "|/usr/share/munin/apache_pipelogger" "$v %p %m %B %D %s"
    </IfModule>

2) Install the log parser as daemon (watches multiple access logs in a single folder for changes)
  - the log parser should run as root (can simply be run in background)
  - slightly less performant, but easier to apply to existing installations
  - If you want response time stats, you have to log them in apache:
  <IfModule mod_log_config.c>
    LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %D" combined-time
  </IfModule>
  - Configure the log parser to match your installation regarding naming and log folders

You can use both solutions simultaneously, the data will be merged.
Be aware that a apache log CustomLog directive in the master config will only log those vhosts that have no directive of their own.

Install plugin conf (after [apache_*])

  [apache_vhosts]
  user root
  env.subgraphs requests bytes time
  env.checks requests bytes time

=over 4

=item user - probably necessary for shared memory IPC

=item subgraphs - create multigraph subgraphs (watch your graphing performance...), default 0

=item checks - enable stats on bytes and response times per request, you have to log these in apache

=back

A word on performance:
Requests/sec should not be much of a problem.  Pipelogger and Logparser should not have man performance problems, as the apply one regex per line and add some stats.
Stats are saved every n seconds (default: 7) to shared mem in serialized format. That should be ok on the most loaded servers (unless you watch cache logs).
I would estimate that > 10k log lines/sec could start becoming a problem, you might have to start tuning there or use a dedicated system.
You might think about splitting the logs over multiple Logparser scripts to parallelize and merge in larger intervals.

Graphing is another matter, the more vhosts you have.
With subgraphs off, you do 3 main graphs * 4 timescales (day, week, month, year).
With subgraphs on, you get 2 checks * (1 + 6 * #vhosts) + 1 check * (1 + #vhosts * #statuscodes * 4)
With hundreds of vhosts that becomes a problem, as munin-update and munin-html do not scale well.

Timeouts are another matter, munin-updates calls for the plugin-data and works on the received lines while the network timeout is running.
So expect to set your timeouts to 120s with a hundred vhosts.

=head1 MAGIC MARKERS

  #%# family=auto
  #%# capabilities=autoconf

=head1 LICENSE

GPLv2

=cut


my %checks = map {$_=>1} ( ($ENV{'checks'}) ? split(/ /,$ENV{'checks'}) : qw(requests bytes time) );
my %subgraphs= map {$_=>1} ( ($ENV{'subgraphs'}) ? split(/ /,$ENV{'subgraphs'}) : () );

use strict;
#use warnings;
use Munin::Plugin;
use IPC::ShareLite ':lock';
use Storable qw(freeze thaw);

my $share = IPC::ShareLite->new(
	-key     => 'mapl',
	-create  => 0,
	-destroy => 0,
	-exclusive => 0,
	-mode => '0744'
) or die $!;


my %data=eval{%{thaw($share->fetch)}};  # using eval to suppress thaw error on empty string at the first run

if ( defined $ARGV[0] and $ARGV[0] eq "autoconf" ) {
  if (scalar(keys %data)>0) {
    print "yes\n";
    exit 0;
  } else {
    print "no data available, apache_pipelogger not installed\n";
    exit 0;
  }
}

need_multigraph();


my ($config,$values);


#
# config
#

if ( defined $ARGV[0] and $ARGV[0] eq "config" ) {
  foreach my $check (keys %checks) {
  next if ($check eq 'requests'); # requests are special
  my $order=join("_$check ",sort keys %data)."_$check";

#
# config: bytes / time + subgraphs
#

    print <<END;

multigraph apache_vhosts_$check
graph_title average $check on all active vhosts
graph_args --base 1000
graph_vlabel average $check per response
graph_category webserver
graph_period minute
graph_order $order
END

    foreach my $site (keys %data) {
      print <<END;
${site}_$check.label $data{$site}{'label'}
${site}_$check.info average $check per response on $data{$site}{'label'}
${site}_$check.draw LINE1
${site}_$check.type GAUGE
END
    } # end sites

    if ($subgraphs{'$check'}) {
      foreach my $site (keys %data) {
      print <<END;

multigraph apache_vhosts_$check.$site
graph_title average $check on $data{$site}{'label'}
graph_args --base 1000
graph_vlabel average response in $check
graph_category webserver
graph_period minute
END

        foreach my $graph ("avg","max") {
          print <<END;
${site}_${graph}_$check.label $graph$check
${site}_${graph}_$check.info $graph$check per response on $data{$site}{'label'}
${site}_${graph}_$check.draw LINE1
${site}_${graph}_$check.type GAUGE
END
        } # end graph
      } # end sites
    } # end subgraph
  } # end checks



#
# config: requests + subgraphs
#
my $order=join("_requests ",sort keys %data)."_requests";

  print <<END;

multigraph apache_vhosts_requests
graph_title requests by vhost
graph_args --base 1000
graph_vlabel requests / \${graph_period}
graph_category webserver
graph_period minute
graph_order $order
END
  foreach my $site (keys %data) {

    print <<END;
${site}_requests.label $data{$site}{'label'}
${site}_requests.info $site
${site}_requests.draw LINE1
${site}_requests.type GAUGE
END

  } # end site

  if ($subgraphs{'requests'}) {

#  multigraphs multivalue (status codes)
    foreach my $site (keys %data) {
      print <<END;

multigraph apache_vhosts_requests.$site
graph_title status codes on $data{$site}{'label'}
graph_args --base 1000
graph_vlabel status codes / \${graph_period}
graph_category webserver
graph_period minute
END
      my $draw='AREA';
      foreach my $status (sort keys %{$data{$site}{'status'}}) {
            print <<END;
${site}_s${status}.label status $status
${site}_s${status}.info status $status
${site}_s${status}.draw $draw
${site}_s${status}.type GAUGE
END
        $draw='STACK';
      } # end status
    } # end sites
  } # end multigraph

  exit 0;
} # end if config




#
# values: bytes / time + subgraphs
#

foreach my $check (keys %checks) {
  next if ($check eq 'requests'); # requests are special

  # main graphs values
  print "\nmultigraph apache_vhosts_$check\n";
  foreach my $site (keys %data) {
    $data{$site}{$check}||=0;
    print "${site}_$check.value $data{$site}{'avg_'.$check}\n";
  } # end sites

  if ($subgraphs{$check}) {
    # subgraph values
    foreach my $site (keys %data) {
      print "\nmultigraph apache_vhosts_$check.$site\n";
      foreach my $graph ("avg","max") {
        $data{$site}{$check}||=0;
        print "${site}_${graph}_$check.value ".$data{$site}{$graph."_".$check}."\n";
      } # end graph
    } # end sites
  } # end subgraph
} # end checks




#
# values: requests + subgraphs
#

print "\nmultigraph apache_vhosts_requests\n";
foreach my $site (keys %data) {
  $data{$site}{'requests'}||=0;
  print "${site}_requests.value $data{$site}{'requests'}\n";
} # end sites

if ($subgraphs{'requests'}) {
  # multigraphs multivalue (status codes)
  foreach my $site (keys %data) {
    print "\nmultigraph apache_vhosts_requests.$site\n";
    foreach my $status (sort keys %{$data{$site}{'status'}}) {
      $data{$site}{'status'}{$status}||=0;
      print "${site}_${status}.value ".($data{$site}{'status'}{$status}||0)."\n";
    }# end status
  } # end sites
} # end subgraph




#
# clear data after poll
#

foreach my $site (keys %data) {
  foreach my $check ( qw(requests bytes time max_bytes avg_bytes max_time avg_time) ) {
    $data{$site}{$check}=0;
  }
  foreach my $val (keys %{$data{$site}{'status'}}) {
     $data{$site}{'status'}{$val}=0;
  }
};

$share->lock(LOCK_EX);
$share->store( freeze \%data );
$share->unlock();

exit 0;
# vim:syntax=perl