Munin contributed plugins

#!/usr/bin/perl

# -*- perl -*-

#

# varnish4_ - Munin plugin to for Varnish 4.x

# Copyright (C) 2009  Redpill Linpro AS

#

# Author: Kristian Lyngstol <kristian@bohemians.org>

#

# 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 2 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, write to the Free Software Foundation, Inc.,

# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

=head1 NAME

varnish4_ - Munin plugin to monitor various aspects of varnish

=head1 APPLICABLE SYSTEMS

Varnish 4.x with varnishstat

=head1 CONFIGURATION

The plugin needs to be able to execute varnishstat.

The configuration section shows the defaults

  [varnish4_*]

     env.varnishstat varnishstat

     env.name

env.varnishstat can be a full path to varnishstat if it's

not in the path already.

env.name is blank (undefined) by default and can be used to specify a -n

name argument to varnish if multiple instances are running on the same

server.

A few aspects are not linked by default. They are marked as

'DEBUG' => 'yes' (or any other value). They are:

vcl, bans, bans_lurker, lru, objects_per_objhead,

losthdr, esi, hcb, shm, shm_writes, overflow,

session, session_herd, gzip

You can link them yourself with something like this:

  ln -s @@LIBDIR@@/plugins/varnish4_ \

    @@CONFDIR@@/plugins/varnish4_data_structures

=head1 INTERPRETATION

Each graph uses data from varnishstat.

=head1 MAGIC MARKERS

 #%# family=auto

 #%# capabilities=autoconf suggest

=head1 VERSION

 $Id$

=head1 BUGS

The hit_rate graph requires munin r2040 or newer to display

correctly.

=head1 PATCHES-TO

Please send patches to Kristian Lyngstol <kristian@bohemians.org>

and/or varnish-misc@varnish-cache.org for significant changes. Munin SVN

is the authoritative repository for this plugin.

=head1 AUTHOR

Kristian Lyngstol <kristian@bohemians.org>

=head1 MODIFICATIONS

Ingo Oppermann <ingo.oppermann@gmail.com>

=head1 LICENSE

GPLv2

=cut

use XML::Parser;

use strict;

# Set to 1 to enable output when a variable is defined in a graph but

# omitted because it doesn't exist in varnishstat.

my $DEBUG = 0;

# Set to 1 to ignore 'DEBUG' and suggest all available aspects.

my $FULL_SUGGEST = 0;

# Varnishstat executable. Include full path if it's not in your path.

my $varnishstatexec = exists $ENV{'varnishstat'} ? $ENV{'varnishstat'} : "varnishstat";

# For multiple instances

my $varnishname = exists $ENV{'name'} ? $ENV{'name'} : undef;

my $self; # Haha, myself, what a clever pun.

# Parameters that can be defined on top level of a graph. Config will print

# them as "graph_$foo $value\n"

my @graph_parameters = ('title','total','order','scale','vlabel','args');

# Parameters that can be defined on a value-to-value basis and will be

# blindly passed to config. Printed as "$fieldname.$param $value\n".

#

# 'label' is hardcoded as it defaults to a varnishstat-description if not

# set.

my @field_parameters = ('graph', 'min', 'max', 'draw', 'cdef', 'warning',

			'colour', 'info', 'type');

# Varnishstat data is stored here. Example

# ('n_vbe' => { 'value' => '124', 'description'=>...,'flag'=>... }, SMA =>

# { s0 => { 'value' => '...', 'flag'=> '...' },'Transient' => ...})

# Both dynamic and static counters are kept here.

#

# Notes:

#  - The 'flag' field for a counter is in RRD-dialect, not varnishstat

my %data;

# Data structure that defines all possible graphs (aspects) and how they

# are to be plotted. Every top-level entry is a graph/aspect. Each

# top-level graph MUST have title set and 'values'.

#

# The 'values' hash must have at least one value definition. The actual

# value used is either fetched from varnishstat based on the value-name, or

# if 'rpn' is defined: calculated. 'type' SHOULD be set.

#

# Graphs with 'DEBUG' set to anything is omitted from 'suggest'.

#

# 'rpn' on values allows easy access to graphs consisting of multiple

# values from varnishstat. (Reverse polish notation). The RPN

# implementation only accepts +-*/ and varnishstat-values.

#

# With the exception of 'label', which is filled with the

# varnishstat-description if left undefined, any value left undefined will

# be left up to Munin to define/ignore/yell about.

#

# For dynamic counters, the values listed need to specify a counter and

# family. This will plot the specified counter for each identity within

# that family. Example: family of SMA, counter c_fail. This will create a

# c_fail-counter for each of the SMA-identities (e.g: Transient, s0, etc).

# For dynamic graphs, the value-name is only used to identify the data

# point, and does not relate to any varnishstat data as that is set by

# family/counter.

#

# Note that dynamic counters fetch the type from the XML and things like

# min/max are currently not supported (and silently ignored).

#

# See munin documentation or rrdgraph/rrdtool for more information.

my %ASPECTS = (

	'request_rate' => {

		'title' => 'Request rates',

		'order' => 'cache_hit cache_hitpass cache_miss '

			 . 'backend_conn backend_unhealthy '

			 . 'client_req client_conn' ,

		'values' => {

			'sess_conn' => {

				'type' => 'DERIVE',

				'min' => '0',

				'colour' => '444444',

				'graph' => 'ON'

			},

			'client_req' => {

				'type' => 'DERIVE',

				'colour' => '111111',

				'min' => '0'

			},

			'cache_hit' => {

				'type' => 'DERIVE',

				'draw' => 'AREA',

				'colour' => '00FF00',

				'min' => '0'

			},

			'cache_hitpass' => {

				'info' => 'Hitpass are cached passes: An '

					. 'entry in the cache instructing '

					. 'Varnish to pass. Typically '

					. 'achieved after a pass in '

					. 'vcl_fetch.',

				'type' => 'DERIVE',

				'draw' => 'STACK',

				'colour' => 'FFFF00',

				'min' => '0'

			},

			'cache_miss' => {

				'type' => 'DERIVE',

				'colour' => 'FF0000',

				'draw' => 'STACK',

				'min' => '0'

			},

			'backend_conn' => {

				'type' => 'DERIVE',

				'colour' => '995599',

				'min' => '0'

			},

			'backend_unhealthy' => {

				'type' => 'DERIVE',

				'min' => '0',

				'colour' => 'FF55FF'

			},

			's_pipe' => {

				'type' => 'DERIVE',

				'min' => '0',

				'colour' => '1d2bdf'

			},

			's_pass' => {

				'type' => 'DERIVE',

				'min' => '0',

				'colour' => '785d0d'

			}

		}

	},

	'hit_rate' => {

		'title' => 'Hit rates',

		'order' => 'client_req cache_hit cache_miss '

			 . 'cache_hitpass' ,

		'vlabel' => '%',

		'args' => '-u 100 --rigid',

		'scale' => 'no',

		'values' => {

			'client_req' => {

				'type' => 'DERIVE',

				'min' => '0',

				'graph' => 'off'

			},

			'cache_hit' => {

				'type' => 'DERIVE',

				'min' => '0',

				'draw' => 'AREA',

				'cdef' => 'cache_hit,client_req,/,100,*'

			},

			'cache_miss' => {

				'type' => 'DERIVE',

				'draw' => 'STACK',

				'min' => '0',

				'cdef' => 'cache_miss,client_req,/,100,*'

			},

			'cache_hitpass' => {

				'type' => 'DERIVE',

				'draw' => 'STACK',

				'min' => '0',

				'cdef' => 'cache_hitpass,client_req,/,100,*'

			},

		}

	},

	'backend_traffic' => {

		'title' => 'Backend traffic',

		'values' => {

			'backend_conn' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'backend_unhealthy' => {

				'type' => 'DERIVE',

				'min' => '0',

				'warning' => ':1'

			},

			'backend_busy' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'backend_fail' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'backend_reuse' => {

				'type' => 'DERIVE',

				'min' => 0

			},

			'backend_recycle' => {

				'type' => 'DERIVE',

				'min' => 0

			},

			'backend_toolate' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'backend_retry' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'backend_req' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'objects' => {

		'title' => 'Number of objects',

		'values' => {

			'n_object' => {

				'type' => 'GAUGE',

				'label' => 'Number of objects'

			},

			'n_objectcore' => {

				'type' => 'GAUGE',

				'label' => 'Number of object cores'

			},

			'n_vampireobject' => {

				'type' => 'GAUGE',

				'label' => 'Number of unresurrected objects'

			},

			'n_objecthead' => {

				'type' => 'GAUGE',

				'label' => 'Number of object heads',

				'info' => 'Each object head can have one '

					. 'or more object attached, '

					. 'typically based on the Vary: header'

			}

		}

	},

	'transfer_rates' => {

		'title' => 'Transfer rates',

		'order' => 's_resp_bodybytes s_resp_hdrbytes',

		'args' => '-l 0',

		'vlabel' => 'bit/s',

		'values' => {

			's_resp_hdrbytes' => {

				'type' => 'DERIVE',

				'label' => 'Header traffic',

				'draw' => 'STACK',

				'min' => '0',

				'info' => 'HTTP Header traffic. TCP/IP '

					. 'overhead is not included.',

				'cdef' => 's_resp_hdrbytes,8,*'

			},

			's_resp_bodybytes' => {

				'type' => 'DERIVE',

				'draw' => 'AREA',

				'label' => 'Body traffic',

				'min' => '0',

				'cdef' => 's_resp_bodybytes,8,*'

			}

		}

	},

	'threads' => {

		'title' => 'Thread status',

		'values' => {

			'threads' => {

				'type' => 'GAUGE',

				'min' => '0',

				'warning' => '1:'

			},

			'threads_created' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'threads_failed' => {

				'type' => 'DERIVE',

				'min' => '0',

				'warning' => ':1'

			},

			'threads_limited' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'threads_destroyed' => {

				'type' => 'DERIVE',

				'min' => '0',

				'warning' => ':1'

			}

		}

	},

	'memory_usage' => {

		'title' => 'Memory usage',

		'args' => '--base 1024',

		'vlabel' => 'bytes',

		'values' => {

			'sms_balloc' => {

				'type' => 'GAUGE',

			},

			'sms_nbytes' => {

				'type' => 'GAUGE',

			},

			'SMA_1' => {

				'counter' => 'g_bytes',

				'family' => 'SMA',

			},

			'SMA_2' => {

				'counter' => 'g_space',

				'family' => 'SMA',

			},

			'SMA_3' => {

				'counter' => 'c_bytes',

				'family' => 'SMA'

			},

			'SMF_1' => {

				'counter' => 'g_bytes',

				'family' => 'SMF',

			},

			'SMF_2' => {

				'counter' => 'g_space',

				'family' => 'SMF',

			}

		}

	},

	'uptime' => {

		'title' => 'Varnish uptime',

		'vlabel' => 'days',

		'scale' => 'no',

		'values' => {

			'uptime' => {

				'type' => 'GAUGE',

				'cdef' => 'uptime,86400,/'

			}

		}

	},

	'objects_per_objhead' => {

		'title' => 'Objects per objecthead',

		'DEBUG' => 'yes',

		'values' => {

			'obj_per_objhead' => {

				'type' => 'GAUGE',

				'label' => 'Objects per object heads',

				'rpn' => [ 'n_object','n_objecthead','/' ]

			}

		}

	},

	'losthdr' => {

		'title' => 'HTTP Header overflows',

		'DEBUG' => 'yes',

		'values' => {

			'losthdr' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'hcb' => {

		'title' => 'Critbit data',

		'DEBUG' => 'yes',

		'values' => {

			'hcb_nolock' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'hcb_lock' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'hcb_insert' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'esi' => {

		'title' => 'ESI',

		'DEBUG' => 'yes',

		'values' => {

			'esi_parse' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'esi_errors' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'esi_warnings' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'session' => {

		'title' => 'Sessions',

		'DEBUG' => 'yes',

		'values' => {

			'sess_conn' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_drop' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_fail' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_pipe_overflow' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_queued' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_dropped' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_closed' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_pipeline' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sess_readahead' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'session_herd' => {

		'title' => 'Session herd',

		'DEBUG' => 'yes',

		'values' => {

			'sess_herd' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'shm_writes' => {

		'title' => 'SHM writes and records',

		'DEBUG' => 'yes',

		'values' => {

			'shm_records' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'shm_writes' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'shm' => {

		'title' => 'Shared memory activity',

		'DEBUG' => 'yes',

		'values' => {

			'shm_flushes' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'shm_cont' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'shm_cycles' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'allocations' => {

		'title' => 'Memory allocation requests',

		'DEBUG' => 'yes',

		'values' => {

			'sm_nreq' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sma_nreq' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'sms_nreq' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'vcl' => {

		'title' => 'VCL',

		'DEBUG' => 'yes',

		'values' => {

			'n_backend' => {

				'type' => 'GAUGE'

			},

			'n_vcl' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'n_vcl_avail' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'n_vcl_discard' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'bans' => {

		'title' => 'Bans',

		'DEBUG' => 'yes',

		'values' => {

			'bans' => {

				'type' => 'GAUGE'

			},

			'bans_added' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'bans_deleted' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'bans_completed' => {

				'type' => 'GAUGE'

			},

			'bans_obj' => {

				'type' => 'GAUGE'

			},

			'bans_req' => {

				'type' => 'GAUGE'

			},

			'bans_tested' => {

				'type' => 'DERIVE',

                                'min' => '0'

			},

			'bans_obj_killed' => {

				'type' => 'DERIVE',

                                'min' => '0'

			},

			'bans_tests_tested' => {

				'type' => 'DERIVE',

                                'min' => '0'

			},

			'bans_dups' => {

				'type' => 'GAUGE'

			},

			'bans_persisted_bytes' => {

				'type' => 'GAUGE'

			},

			'bans_persisted_fragmentation' => {

				'type' => 'GAUGE'

			}

		}

	},

	'bans_lurker' => {

		'title' => 'Ban Lurker',

		'DEBUG' => 'yes',

		'values' => {

			'bans_lurker_tested' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'bans_lurker_tests_tested' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'bans_lurker_obj_killed' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'bans_lurker_contention' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'expunge' => {

		'title' => 'Object expunging',

		'values' => {

			'n_expired' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'n_lru_nuked' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'lru' => {

		'title' => 'LRU activity',

		'DEBUG' => 'yes',

		'values' => {

			'n_lru_nuked' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'n_lru_moved' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	},

	'bad' => {

		'title' => 'Misbehavior',

		'values' => {

			'SMA_1' => {

				'counter' => 'c_fail',

				'family' => 'SMA',

			},

			'SMF_1' => {

				'counter' => 'c_fail',

				'family' => 'SMF',

			},

			'sess_drop' => {

				'type' => 'DERIVE'

			},

			'backend_unhealthy' => {

				'type' => 'DERIVE'

			},

			'fetch_failed' => {

				'type' => 'DERIVE'

			},

			'backend_busy' => {

				'type' => 'DERIVE'

			},

			'threads_failed' => {

				'type' => 'DERIVE'

			},

			'threads_limited' => {

				'type' => 'DERIVE'

			},

			'threads_destroyed' => {

				'type' => 'DERIVE'

			},

			'thread_queue_len' => {

				'type' => 'GAUGE'

			},

			'losthdr' => {

				'type' => 'DERIVE'

			},

			'esi_errors' => {

				'type' => 'DERIVE'

			},

			'esi_warnings' => {

				'type' => 'DERIVE'

			},

			'sess_fail' => {

				'type' => 'DERIVE'

			},

			'sess_pipe_overflow' => {

				'type' => 'DERIVE'

			}

		}

	},

	'gzip' => {

		'title' => 'GZIP activity',

		'DEBUG' => 'yes',

		'values' => {

			'n_gzip' => {

				'type' => 'DERIVE',

				'min' => '0'

			},

			'n_gunzip' => {

				'type' => 'DERIVE',

				'min' => '0'

			}

		}

	}

);

################################

# Various helper functions     #

################################

# Translate $_[0] from varnish' internal types (flags) to munin/rrd

# variants (e.g: from 'i' to GAUGE). Returns the result.

sub translate_type

{

	my $d = $_[0];

	if ($d eq "i") {

		$d = "GAUGE";

	} elsif ($d eq "a") {

		$d = "DERIVE";

	}

	return $d;

}

# Print the value of a two-dimensional hash if it exist.

# Returns false if non-existent.

#

# Output is formatted for plugins if arg4 is blank, otherwise arg4 is used

# as the title/name of the field (ie: arg4=graph_title).

sub print_if_exist

{

	my %values = %{$_[0]};

	my $value = $_[1];

	my $field = $_[2];

	my $title = "$value.$field";

	if (defined($_[3])) {

		$title = $_[3];

	}

	if (defined($values{$value}{$field})) {

		print "$title $values{$value}{$field}\n";

	} else {

		return 0;

	}

}

# Create a output-friendly name

sub normalize_name

{

	my $name = $_[0];

	$name =~ s/[^a-zA-Z0-9]/_/g;

	return $name;

}

# Braindead RPN: +,-,/,* will pop two items from @stack, and perform

# the relevant operation on the items. If the item in the array isn't one

# of the 4 basic math operations, a value from varnishstat is pushed on to

# the stack. IE: 'client_req','client_conn','/' will leave the value of

# "client_req/client_conn" on the stack.

#

# If only one item is left on the stack, it is printed. Otherwise, an error

# message is printed.

sub rpn

{

	my @stack;

	my $left;

	my $right;

	foreach my $item (@{$_[0]}) {

		if ($item eq "+") {

			$right = pop(@stack);

			$left = pop(@stack);

			push(@stack,$left+$right);

		} elsif ($item eq "-") {

			$right = pop(@stack);

			$left = pop(@stack);

			push(@stack,$left-$right);

		} elsif ($item eq "/") {

			$right = pop(@stack);

			$left = pop(@stack);

			push(@stack,$left/$right);

		} elsif ($item eq "*") {

			$right = pop(@stack);

			$left = pop(@stack);

			push(@stack,$left*$right);

		} else {

			push(@stack,int($data{$item}{'value'}));

		}

	}

	if (@stack > 1)

	{

		print STDERR "RPN error: Stack has more than one item left.\n";

		print STDERR "@stack\n";

		exit 255;

	}

	print "@stack";

	print "\n";

}

# Bail-function.

sub usage

{

	if (@_) {

		print STDERR "@_" . "\n\n";

	}

	print STDERR "Known arguments: suggest, config, autoconf.\n";

	print STDERR "Run with suggest to get a list of known aspects.\n";

	exit 1;

}

################################

# XML Parsing                  #

################################

# The following code is for parsing varnishstat -x. While %data should be

# stable, the following bits can easily be replaced with anything (json, an

# other xml-parser, magic, etc)

#

# The basic concept is simple enough. Only worry about stuff inside

# <state>. Updating %state on each new data field, and commit it to %data

# when </state> is seen.

#

# We do use translate_type() on the 'flag' field.

# Internal state for the XML parsing

my %state = (

	'stat' => 0,     # inside <stat> or not

	'field' => 'none', # <name>, <value>, <stat>, etc.

);

# Reset the state of XML, mainly used for end-elements.

sub xml_reset_state() {

	$state{'stat'} = '0';

	$state{'field'} = 'none';

	$state{'values'} = ();

}

# Callback for data entry. Cleans leading whitespace and updates state.

sub xml_characters {

	my $d = $_[1];

	if ($state{'stat'} == 0) {

		return;

	}

	if ($state{'field'} eq "type" && $d eq "MAIN") {

		return;

	}

	$d =~ s/^\s*$//g;

	if ($d eq "") {

		return;

	}

	$state{'values'}{$state{'field'}} = $d;

}

# Store the current state in %data. Issued at </stat>

# Note that 'flag' is translated to RRD-equivalents here.

sub xml_commit_state

{

	my $name = $state{'values'}{'name'};

	my $type = $state{'values'}{'type'};

	my $ident = $state{'values'}{'ident'};

	foreach my $key (keys %{$state{'values'}}) {

		my $data = $state{'values'}{$key};

		if ($key eq 'flag') {

			$data = translate_type($data);

		}

		if (defined($type) and $type ne "" and defined($ident) and $ident ne "") {

			$data{$type}{$ident}{$name}{$key} = $data;

		} else {

			$data{$name}{$key} = $data

		}

	}

}

# Callback for end tag. E.g: </stat>

sub xml_end_elem {

	my $element = $_[1];

	if ($element ne "stat") {

		return;

	}

	xml_commit_state();

	xml_reset_state();

}

# Callback for opening tag. E.g: <stat>

sub xml_start_elem {

	$state{'field'} = $_[1];

	if ($state{'field'} eq "stat") {

		$state{'stat'} = 1;

	}

}

################################

# Internal API                 #

################################

# Populate %data, includes both values and descriptions and more.

# Currently driven by XML, but that could change.

sub populate_stats

{

	my $arg = "-x";

	my $parser = new XML::Parser(Handlers => {Start => \&xml_start_elem,

						End => \&xml_end_elem,

						Char => \&xml_characters} );

	if ($varnishname) {

		$arg .= " -n $varnishname";

	}

	open (XMLDATA, "$varnishstatexec $arg|") or die "meh";

	$parser->parse(*XMLDATA, ProtocolEncoding => 'ISO-8859-1');

	close(XMLDATA);

}

# Prints the fields in the list in $_[2] (e.g: 'value'/'description') for

# each identity of the varnish counter/family combination as defined by

# the $_[0]-counter on the aspect definition. Err, that's jibberish, so

# an example:

#

# e.g: dynamic_print('SMA_1','',('value'))

# e.g: dynamic_print('SMA_2','.label',('ident','description'))

# SMA_1 is the counter-value. If it is a dynamic counter, it has a counter

# and family-member (e.g: counter: c_req, family: SMA) and print_dynamic

# will print c_req for each SMA-identity.

#

# Note that the variables to print is a list. This is to allow printing a

# single item with multiple fields. Typically for identity+description so

# you can distinguish between different data points.

#

# Returns true if it was a dynamic counter.

sub print_dynamic

{

	my $name = $_[0];

	shift;

	my $suffix = $_[0];

	shift;

	my @field = @_;

	if (!defined($ASPECTS{$self}{'values'}{$name}{'counter'})) {

		return 0;

	}

	if (!defined($ASPECTS{$self}{'values'}{$name}{'family'})) {

		return 0;

	}

	my $counter = $ASPECTS{$self}{'values'}{$name}{'counter'};

	my $type = $ASPECTS{$self}{'values'}{$name}{'family'};

	foreach my $key (keys %{$data{$type}}) {

		my $pname = normalize_name($type . "_" . $key . "_" . $counter);

		print $pname . $suffix . " ";

		my $i = 0;

		foreach my $f (@field) {

			if ($i != 0) {

				print " ";

			}

			$i += 1;

			print $data{$type}{$key}{$counter}{$f};

		}

		print "\n";

	}

	return 1;

}

# Read and verify the aspect ($self).

sub set_aspect

{

	$self = $0;

	$self =~ s/^.*\/varnish[0-9]?_//;

	if (!defined($ASPECTS{$self}) && @ARGV == 0) {

		usage "No such aspect";

	}

}

# Print 'yes' if it's reasonable to use this plugin, or 'no' with a

# human-readable error message. Always exit true, even if the response

# is 'no'.

sub autoconf

{

	# XXX: Solaris outputs errors to stderr and always returns true.

	# XXX: See #873

	if (`which $varnishstatexec 2>/dev/null` =~ m{^/}) {

		print "yes\n";

	} else {

		print "no ($varnishstatexec could not be found)\n";

	}

	exit 0;

}

# Suggest relevant aspects/values of $self.

# 'DEBUG'-graphs are excluded.

sub suggest

{

	foreach my $key (keys %ASPECTS) {

		if (defined($ASPECTS{$key}{'DEBUG'}) && $FULL_SUGGEST != 1) {

			next;

		}

		print "$key\n";

	}

}

# Walk through the relevant aspect and print all top-level configuration

# values and value-definitions.

sub get_config

{

	my $graph = $_[0];

	# Need to double-check since set_aspect only checks this if there

	# is no argument (suggest/autoconf doesn't require a valid aspect)

	if (!defined($ASPECTS{$graph})) {

		usage "No such aspect";

	}

	my %values = %{$ASPECTS{$graph}{'values'}};

	print "graph_category Varnish\n";

	foreach my $field (@graph_parameters) {

		print_if_exist(\%ASPECTS,$graph,$field,"graph_$field");

	}

	foreach my $value (keys %values) {

		# Just print the description/type if it's a dynamic

		# counter. It'll be silent if it isn't.

		if(print_dynamic($value,'.label',('description','type','ident'))) {

			print_dynamic($value,'.type',('flag'));

			next;

		}

		# Need either RPN definition or a varnishstat value.

		if (!defined($data{$value}{'value'}) &&

		    !defined($values{$value}{'rpn'})) {

			if ($DEBUG) {

				print "ERROR: $value not part of varnishstat.\n"

			}

			next;

		}

		if (!print_if_exist(\%values,$value,'label')) {

			print "$value.label $data{$value}{'description'}\n";

		}

		foreach my $field (@field_parameters) {

			print_if_exist(\%values,$value,$field);

		}

	}

}

# Handle arguments (config, autoconf, suggest)

# Populate stats for config is necessary, but we want to avoid it for

# autoconf as it would generate a nasty error.

sub check_args

{

	if (@ARGV && $ARGV[0] eq '') {

		shift @ARGV;

	}

	if (@ARGV == 1) {

		if ($ARGV[0] eq "config") {

			populate_stats;

			get_config($self);

			exit 0;

		} elsif ($ARGV[0] eq "autoconf") {

			autoconf($self);

			exit 0;

		} elsif ($ARGV[0] eq "suggest") {

			suggest;

			exit 0;

		}

		usage "Unknown argument";

	}

}

################################

# Execution starts here        #

################################

set_aspect;

check_args;

populate_stats;

# We only get here if we're supposed to.

# Walks through the relevant values and either prints the varnishstat, or

# if the 'rpn' variable is set, calls rpn() to execute ... the rpn.

#

# NOTE: Due to differences in varnish-versions, this checks if the value

# actually exist before using it.

foreach my $value (keys %{$ASPECTS{$self}{'values'}}) {

	if (defined($ASPECTS{$self}{'values'}{$value}{'rpn'})) {

		print "$value.value ";

		rpn($ASPECTS{$self}{'values'}{$value}{'rpn'});

	} else {

		if (print_dynamic($value,'.value',('value'))) {

			next;

		}

		if (!defined($data{$value}{'value'})) {

			if ($DEBUG) {

				print STDERR "Error: $value not part of "

					   . "varnishstat.\n";

			}

			next;

		}

		print "$value.value ";

		print "$data{$value}{'value'}\n";

	}

}