#!/usr/bin/python
#%# family=auto
#%# capabilities=suggest autoconf


"""
Munin plugin to monitor NSD3 statistics
J.T.Sage <jtsage@gmail.com>, 2010/06/10

To use:
ln -s path_to_this_script /etc/munin/plugins/nsd

Configuration
[nsd]
	user nsd
	env.statsfile /var/log/nsd.log
	env.pidfile /var/run/nsd3/nsd.pid

Notes:
  Note that the plugin has a built in half second pause for the lastest NSD3 
  statistics to write.  This is done via a SIGUSR1 signal to the process.  
  If your system is sufficiently loaded to the point that half a second
  is not enough time for the file to be written to, please update that 
  number in the source.  It should be more than long enough for most
  users.
"""

import os
import sys
import subprocess
import time
import re

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

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"
    print "a.label A"
    print "a.type DERIVE"
    print "a.min 0"
    print "aaaa.label AAAA"
    print "aaaa.type DERIVE"
    print "aaaa.min 0"
    print "ptr.label PTR"
    print "ptr.type DERIVE"
    print "ptr.min 0"
    print "mx.label MX"
    print "mx.type DERIVE"
    print "mx.min 0"
    print "type252.label AXFR"
    print "type252.type DERIVE"
    print "type252.min 0"
    print "snxd.label NXDOMAIN"
    print "snxd.type DERIVE"
    print "snxd.min 0"
    print "rq.label Total Successful"
    print "rq.type DERIVE"
    print "rq.min 0"
  

def print_values():
    """Gets NSD's latest stats."""
    
    pidf = open(PID_FILE, 'r')
    pidn = pidf.read()
    pidf.close();
    statscmd = ['kill', '-SIGUSR1']
    statscmd.append(pidn.strip())
    dropstats = subprocess.call(statscmd)

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

    matches = re.compile(' A=(\d+)').findall(nstats[-1])
    if matches == []:
        print "a.value 0"
    else:
        print "a.value " + matches[0]

    matches = re.compile(' AAAA=(\d+)').findall(nstats[-1])
    if matches == []:
        print "aaaa.value 0"
    else:
        print "aaaa.value " + matches[0]    

    matches = re.compile(' PTR=(\d+)').findall(nstats[-1])
    if matches == []:
        print "ptr.value 0"
    else:
        print "ptr.value " + matches[0]


    matches = re.compile(' MX=(\d+)').findall(nstats[-1])
    if matches == []:
        print "mx.value 0"
    else:
        print "mx.value " + matches[0]

    matches = re.compile(' TYPE252=(\d+)').findall(nstats[-1])
    if matches == []:
        print "type252.value 0"
    else:
        print "type252.value " + matches[0]

    matches = re.compile(' SNXD=(\d+) ').findall(xstats[-1])
    if matches == []:
        print "snxd.value 0"
    else:
        print "snxd.value " + matches[0]

    matches = re.compile(' RQ=(\d+) ').findall(xstats[-1])
    if matches == []:
        print "rq.value 0"
    else:
        print "rq.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':
            print 'yes'
            sys.exit(0)

    if len(sys.argv) > 1 and sys.argv[1] == 'config':
        print_config()
        sys.exit(0)

    print_values()