Munin contributed plugins

#!/usr/bin/env python

#%# family=auto

#%# capabilities=autoconf

"""

=head1 NAME

	nsd - Munin plugin to monitor the number of queries a running process

	      of nsd3 has recievied.

=head1 APPLICABLE SYSTEMS

	Linux or *nix system with a logging installation of NSD v3 installed.

	  (http://nlnetlabs.nl/projects/nsd/)

=head1 CONFIGURATION

	The plugin needs access to the nsd logfile and the nsd pid file to

	force the running nsd process to write the current statistics.

	Tip: To see if it's already set up correctly, just run this plugin

	with the parameter "autoconf".  If you get a "yes", everything should

	work like a charm already.

	This configuration section shows the defaults of the plugin:

	The stats line is a set of space-separated values that you wish to

	retrieve from NSD.  The format is VALUE=Caption.  For spaces in a

	caption value, replace them with an underscore (_).

	[nsd]

	        env.statsfile /var/log/nsd.log

        	env.pidfile /var/run/nsd3/nsd.pid

		env.stats "A=A AAAA=AAAA MX=MX PTR=PTR TYPE252=AXFR SNXD=NXDOMAIN RQ=Total_Successful"

	If you need to set a user for the logfile to be readable, and most

	importantly, the process to receive the signal, you may specify it.

	For example:

	[nsd]

		user nsd

=head1 INTERPRETATION

	The plugin shows the number of queries that nsd has received,

	averaged over a period to gain the number of queries per second.

	For most servers, these values will be very low.  In the event

	of a misconfiguration, the plugin will return undefined values.

=head1 MAGIC MARKERS

	#%# family=auto

	#%# capabilities=autoconf

=head1 VERSION

	v1.0.1

=head1 AUTHOR

	J.T.Sage <jtsage@gmail.com>

=head1 LICENSE

	GPLv2

=cut

"""

import os

import sys

import subprocess

import time

import re

import signal

STATS_FILE = os.environ.get('statsfile', '/var/log/nsd.log')

PID_FILE = os.environ.get('pidfile', '/var/run/nsd3/nsd.pid')

STATS_STRING = os.environ.get('stats', "A=A AAAA=AAAA MX=MX PTR=PTR TYPE252=AXFR SNXD=NXDOMAIN RQ=Total_Successful")

BOTH_LISTS = STATS_STRING.split()

def print_config():

	"""Generates and prints a munin config for a given chart."""

	print "graph_title NSD3 Queries"

	print "graph_vlabel qps"

	print "graph_category network"

	print "graph_info Queries per second"

	for x in BOTH_LISTS:

		val = x.split('=')

		name = val[0].lower()

		label = val[1].replace('_', ' ')

		print name + '.label ' + label

		print name + '.type DERIVE'

		print name + '.min 0'

	sys.exit(0)

def print_values():

	"""Gets NSD's latest stats."""

	bigfail = False

	if ( not os.access(STATS_FILE, os.R_OK) ) :

		bigfail = True

	if ( not os.access(PID_FILE, os.R_OK) ) :

		bigfail = True

	if ( not bigfail ):

		pidf = open(PID_FILE, 'r')

		pidn = pidf.read()

		pidf.close();

		try:

			os.kill(int(pidn.strip()), signal.SIGUSR1)

	        except OSError:

			bigfail = True

	time.sleep(.5) # Wait for the log to write.

	if ( not bigfail ):

		statf = open(STATS_FILE, 'r')

		stats = tail(statf, 10)

		nstats = []

		xstats = []

		for line in stats:

			if "XSTATS" in line:

				xstats.append(line.strip())

			if "NSTATS" in line:

				nstats.append(line.strip())

		statsline = nstats[-1] + xstats[-1]

	else:

		statsline = " "

	relist = []

	for x in BOTH_LISTS:

                val = x.split('=')

                name = val[0].lower()

		rxp = val[0]

		relist.append([name, rxp])

	for point in relist:

		matches = re.compile(' '+point[1]+'=(\d+)').findall(statsline)

		if bigfail:

			print point[0]+'.value U'

		elif matches == []:

			print point[0]+'.value 0'

		else:

			print point[0]+'.value '+matches[0]

def tail( f, window=20 ):

	f.seek( 0, 2 )

	bytes = f.tell()

	size = window

	block = -1

	while size > 0 and bytes+block*1024  > 0:

		f.seek( block*1024, 2 ) # from the end!

		data = f.read( 1024 )

		linesFound = data.count('\n')

		size -= linesFound

		block -= 1

	f.seek( block*1024, 2 )

	f.readline() # find a newline

	lastBlocks = list( f.readlines() )

	return lastBlocks[-window:]

if __name__ == '__main__':

	if len(sys.argv) > 1:

		if  sys.argv[1] == 'autoconf':

			if ( not os.path.isfile(STATS_FILE) ) :

				print 'no (Log file not found)'

			elif ( not os.path.isfile(PID_FILE) ) :

				print 'no (PID file not found)'

			elif ( not os.access(STATS_FILE, os.R_OK) ) :

				print 'no (Log file exists, access denied for read)'

                        elif ( not os.access(PID_FILE, os.R_OK) ) :

                                print 'no (PID file exists, access denied for read)'

			else:

				pidf = open(PID_FILE, 'r')

				pidn = pidf.read()

				pidf.close();

				try:

					os.kill(int(pidn.strip()), signal.SIGUSR1)

				except OSError as (errno, strerror):

					print 'no (Unable to signal process :: '+strerror+')'

					sys.exit(0)

				print 'yes'

			sys.exit(0)

	if len(sys.argv) > 1 and sys.argv[1] == 'config':

		print_config()

		sys.exit(0)

	print_values()