Munin contributed plugins

#!/usr/local/bin/perl -w

#%# family=auto

#%# capabilities=autoconf

#

# Copyright (c) 2013 Philip Paeps

# All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions

# are met:

# 1. Redistributions of source code must retain the above copyright

#    notice, this list of conditions and the following disclaimer

#    in this position and unchanged.

# 2. Redistributions in binary form must reproduce the above copyright

#    notice, this list of conditions and the following disclaimer in the

#    documentation and/or other materials provided with the distribution.

#

# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

# SUCH DAMAGE.

#

#

# Plugin to monitor NSD performance.

# Contributed by: Philip Paeps <philip@paeps.cx>.

# Heavily inspired by the unbound_munin_ script by

# W.C.A. Wijgaards and the nsd3 script by J.T.Sage.

#

# Usage: nsd_FUNCTION

#

# Available functions:

#	by_type - incoming queries by type

#	by_rcode - answers by rcode

#	hits - base volume

#

# Example configuration:

#

#   [nsd_*]

#   user bind

#   env.logdir /var/log

#   env.logfile nsd.log

#

#   [nsd_by_type]

#   env.stats = A=A AAAA=AAAA MX=MX PTR=PTR TYPE252=AXFR SOA=SOA

#

# The stats line is an optional space-separated string of VALUE=Caption

# pairs of query types to pick out of the NSTATS returned by NSD.  Replace

# spaces in a caption value by _.

#

use strict;

use Munin::Plugin;

use POSIX;

my $LOGDIR = $ENV{'logdir'} || '/var/log';

my $LOGFILE = $ENV{'logfile'} || 'nsd.log';

my $logfile = "$LOGDIR/$LOGFILE";

my $pidfile = $ENV{'pidfile'} || '/var/run/nsd/nsd.pid';

sub signal_nsd {

	open(my $P, "< $pidfile") || die "Couldn't open pidfile: $!\n";

	my $pid = <$P>;

	close($P);

	chomp $pid;

	kill USR1 => $pid or die "Couldn't signal NSD: $!\n";

	# Give the daemon a chance to write statistics.

	sleep(0.5);

}

sub read_logfile($) {

	my $stats = shift;

	my $pos = undef;

	($pos) = restore_state();

	$pos = 0 unless defined($pos);

	my ($L, $rotated) = tail_open($logfile, $pos);

	my $last = 0;

	while (<$L>) {

		chomp $_;

		if (/([NX]STATS) (\d+)/) {

			$last = $2;

			push @$stats, {

				'type' => $1, 'when' => $2,

				'values' => { $_ =~ m/(\S+)=(\d+)/g },

			};

		}

	}

	$pos = tail_close($L);

	save_state($pos);

	return $last;

}

sub get_values($) {

	my $values = shift;

	my @stats = ();

	my $last = read_logfile(\@stats);

	# If the values found in the logfile are older than three minutes,

	# signal NSD to print fresh ones, and read them again.

	my $now = time;

	if ($now - $last > 3 * 60) {

		signal_nsd();

		read_logfile(\@stats);

	}

	# @stats is an array of the last lines found in the logfile.  Hopefully,

	# the last two lines will be NSTATS and XSTATS.  If not, we need to keep

	# looking.

	foreach (keys %$values) {

		foreach my $stat (reverse(@stats)) {

			$values->{$_} = $stat->{'values'}{$_} if ($stat->{'values'}{$_});

		}

	}

	return \@stats;

}

# Base volume

sub hits($) {

	my $function = shift;

	my %captions = ();

	%captions = (

		'RR' => 'UDP queries dropped',

		'SAns' => 'UDP queries answered',

		'RTCP' => 'TCP connections',

		'SErr' => 'Transmit errors',

	);

	# Print graph configuration.

	if ($function and $function eq "config") {

		print "graph_title NSD DNS traffic\n";

		print "graph_args --base 1000 -l 0\n";

		print "graph_vlabel queries / second\n";

		print "graph_category dns\n";

		foreach my $caption (keys %captions) {

			my $label = $captions{$caption};

			$label =~ s/_/ /;

			print lc($caption) . ".label $label\n";

			print lc($caption) . ".type DERIVE\n";

			print lc($caption) . ".min 0\n";

		}

		print "graph_info Base volume\n";

		exit 0;

	}

	my %values = map { $_ => 0 } keys %captions;

	get_values(\%values);

	foreach (keys %values) {

		print lc($_) . ".value $values{$_}\n";

	}

	exit 0;

}

# DNS queries by type

sub by_type($$) {

	my ($function, $stats) = @_;

	# Sensible default set of statistics.

	if (! $stats) {

		$stats = "A=A AAAA=AAAA MX=MX PTR=PTR TYPE252=AXFR SOA=SOA " .

		    "TXT=TXT DNSKEY=DNSKEY NS=NS SPF=SPF";

	}

	my %captions = map { split /=/ } split / /, $stats;

	# Print graph configuration.

	if ($function and $function eq "config") {

		print "graph_title NSD DNS queries by type\n";

		print "graph_args --base 1000 -l 0\n";

		print "graph_vlabel queries / second\n";

		print "graph_category dns\n";

		foreach my $caption (keys %captions) {

			my $label = $captions{$caption};

			$label =~ s/_/ /;

			print lc($caption) . ".label $label\n";

			print lc($caption) . ".type DERIVE\n";

			print lc($caption) . ".min 0\n";

		}

		print "graph_info Queries by DNS RR type requested\n";

		exit 0;

	}

	my %values = map { $_ => 0 } keys %captions;

	get_values(\%values);

	foreach (keys %values) {

		print lc($_) . ".value $values{$_}\n";

	}

	exit 0;

}

# Answers by rcode

sub by_rcode($) {

	my ($function) = shift;

	my %captions = ();

	%captions = (

		'SAns' => 'NOERROR',

		'SFail' => 'SERVFAIL',

		'SFErr' => 'FORMERR',

		'SNXD' => 'NXDOMAIN',

	);

	# Print graph configuration.

	if ($function and $function eq "config") {

		print "graph_title NSD DNS answers by rcode\n";

		print "graph_args --base 1000 -l 0\n";

		print "graph_vlabel answers / second\n";

		print "graph_category dns\n";

		foreach my $caption (keys %captions) {

			my $label = $captions{$caption};

			$label =~ s/_/ /;

			print lc($caption) . ".label $label\n";

			print lc($caption) . ".type DERIVE\n";

			print lc($caption) . ".min 0\n";

		}

		print "graph_info Answers by rcode returned\n";

		exit 0;

	}

	my %values = map { $_ => 0 } keys %captions;

	get_values(\%values);

	foreach (keys %values) {

		# SAns is the total number of answers sent, regardless of rcode.

		# Subtracting SERVFAIL, FORMERR and NXDOMAIN leaves IMPL and

		# REFUSED.  NSD will never send REFUSED, which leaves IMPL - so,

		# probably correct enough!

		if ($_ eq "SAns") {

			$values{$_} -= $values{'SFErr'};

			$values{$_} -= $values{'SFail'};

			$values{$_} -= $values{'SNXD'};

		}

		print lc($_) . ".value $values{$_}\n";

	}

	exit 0;

}

# Make sure we can access the pidfile and the logfile

# and that we can send a signal to NSD to print stats.

# Note that autoconf should exit 0 even if it fails.

sub autoconf {

	open(my $L, "< $logfile") || print "no ($logfile: $!)\n";

	open(my $P, "< $pidfile") || print "no ($pidfile: $!)\n";

	exit 0 unless defined($L) and defined($P);

	eval { signal_nsd() };

	if ($@) {

		chomp $@;

		warn "no ($@)\n";

		exit 0;

	}

	print "yes\n";

	exit 0;

}

if ($ARGV[0] and $ARGV[0] eq "autoconf") {

	autoconf();

}

if ($Munin::Plugin::me =~ /_by_type$/) {

	by_type($ARGV[0], $ENV{'stats'});

} elsif ($Munin::Plugin::me =~ /_by_rcode$/) {

	by_rcode($ARGV[0]);

} elsif ($Munin::Plugin::me =~ /_hits$/) {

	hits($ARGV[0]);

}

exit 0;