#!/bin/sh

: <<=cut

=head1 NAME

parse Chrony Tracking output for timeserver status information

=head1 APPLICABLE SYSTEMS

Any system with a local chronyd service.

=head1 CONFIGURATION

No configuration.


=head1 VERSION

Revision 0.1 2008/08/23 13:06:00 joti

  First version only chronyc tracking, autodetection included.

Revision 0.2 2008/10/11 16:09:00 joti

  Added scaling of other values to match with frequency, added more description to fields

Revision 0.3 2014/02/16 zjttoefs

  reduce forking by using awk
  do not limit output precision
  add stratum monitoring
  detect slow/fast time or frequency and adjust sign of value accordingly
  remove commented out code

Revision 0.4 2016/11/10 Lars Kruse

  rewrite field handling
  use "which" for "chronyc" location
  switch from "bash" to "sh"
  fix exit code of failing "autoconf"


=head1 AUTHOR

Copyright (C) 2008 joti

Copyright (C) 2014 zjttoefs

Copyright (C) 2016 Lars Kruse <devel@sumpfralle>


=head1 MAGIC MARKERS

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

=cut

CHRONYC="$(which chronyc | head -1)"

# Frequency has extremely higher values than other. Therefore they are fitted by scaling via suitable factors.
# field definitions:
#   - munin fieldname
#   - factor for graph visualization (all values are supposed to reach a similar dimension)
#   - regular expression of the chrony output line (may not contain whitespace, case insensitive)
#   - label (may include "%d" for including the factor; may contain whitespace)
fields="stratum		1	^Stratum		Stratum
	systime		1000	^System.time		System Time (x%d)
	frequency	1	^Frequency		Frequency (ppm)
	residualfreq	100	^Residual.freq		Residual Freq (ppm, x%d)
	skew		100	^Skew			Skew (ppm, x%d)
	rootdelay	1000	^Root.delay		Root delay (seconds, x%d)
	rootdispersion	1000	^Root.dispersion	Root dispersion (seconds, x%d)"

# chrony example output (v2.4.1):
#   Reference ID    : 131.188.3.221 (ntp1.rrze.uni-erlangen.de)
#   Stratum         : 2
#   Ref time (UTC)  : Thu Nov 10 22:39:50 2016
#   System time     : 0.000503798 seconds slow of NTP time
#   Last offset     : +0.000254355 seconds
#   RMS offset      : 0.002186779 seconds
#   Frequency       : 17.716 ppm slow
#   Residual freq   : +0.066 ppm
#   Skew            : 4.035 ppm
#   Root delay      : 0.042980 seconds
#   Root dispersion : 0.005391 seconds
#   Update interval : 258.4 seconds
#   Leap status     : Normal


if [ "$1" = "autoconf" ]; then
	if [ -n "$CHRONYC" ] && [ -x "$CHRONYC" ]; then
		echo yes
	else
		echo "no (missing 'chronyc' executable)"
	fi
	exit 0
fi

if [ "$1" = "config" ]; then
	echo 'graph_title Chrony Tracking Stats'
	echo 'graph_args --base 1000 -l 0'
	echo 'graph_vlabel (seconds,ppm)'
	echo 'graph_category time'
	echo "$fields" | while read fieldname factor regex label; do
		# insert the factor, if "%d" is part of the label
		printf "${fieldname}.label $label\n" "$factor"
		echo "${fieldname}.type GAUGE"
	done
	exit 0
fi

chrony_status="$("$CHRONYC" -n tracking)"
echo "$fields" | while read fieldname factor regex label; do
	status_line="$(echo "$chrony_status" | grep -i -- "$regex " | cut -d ":" -f 2-)"
	if [ -z "$status_line" ]; then
		value="U"
	else
		# the keyword "slow" indicates negative values
		value="$(echo "$status_line" | awk '{ /slow/ ? (SIGN=-1) : (SIGN=1); print $1 * SIGN * '"$factor"' }')"
	fi
	echo "${fieldname}.value $value"
done