[Xymon] Graphs not showing

[W.J.M. Nelis]

Hello,

my previous post was mangled because there were some snippets of HTML in 
it. Therefore the message is posted again, this time without HTML.


the status of audio streams through an Open Digital Radio multiplexer is 
monitored in Xymon. A Perl script retrieves the status and statistics from 
the multiplexer, and sent them to Xymon. The statistics are to be shown in 
graphs. However, while the RR databases are build, no graphs are shown.

I am using debian 8.6 with xymon 4.3.17. (An update to version 4.3.27 
failed, as the configure script does not recognise rrdtool 1.4.8, resulting 
in a version of xymon which does not support trend graphs.) A perl script 
retrieves the status of (the input channels of) the multiplexer, and sends 
the message to xymon. The statistics are included in the format which is 
also used by devmon. The last part of the status message of test odr_mux 
contains the following as HTML comment:

  linecount=2
DEVMON RRD: odr 0 0
DS:PeakLeft:GAUGE:600:-100:100 DS:PeakRight:GAUGE:600:-100:100 \
DS:Underrun:DERIVE:600:0:U DS:Overrun:DERIVE:600:0:U \ 
DS:BufferMin:GAUGE:600:-1:U DS:BufferMax:GAUGE:600:0:U
sub-ozo -90:-90:176972:0:-1:0
sub-urk -90:-90:176972:0:-1:0

In xymonserver.cfg two lines are adapted:

TEST2RRD=".... ,odr_mux=devmon"
GRAPHS=" .... ,odr_mux::1"

The statistics are entered in RRD's:

root at debian:/var/lib/xymon/rrd/OzoNop# ls -l odr*
-rw-r--r-- 1 xymon xymon 114560 Jan  8 19:04 odr.sub-ozo.rrd
-rw-r--r-- 1 xymon xymon 114560 Jan  8 19:04 odr.sub-urk.rrd
root at debian:/var/lib/xymon/rrd/OzoNop#

The graph definition is:

[odr_mux]
      FNPATTERN ^odr\.(.+)\.rrd$
      TITLE , Frame loss rate
      YAXIS Rate [/s]
      DEF:ur at RRDIDX@=@RRDFN@:Underrun:AVERAGE
      DEF:or at RRDIDX@=@RRDFN@:Overrun:AVERAGE
      LINE1:ur at RRDIDX@#FF0000:@RRDPARAM@ underrun
      GPRINT:ur at RRDIDX@:MIN:Min \: %5.1lf %s
      GPRINT:ur at RRDIDX@:MAX:Max \: %5.1lf %s
      GPRINT:ur at RRDIDX@:AVERAGE:Avg \: %5.1lf %s
      GPRINT:ur at RRDIDX@:LAST:Cur \: %5.1lf %s\n
      LINE1:or at RRDIDX@#00FF00:@RRDPARAM@  overrun
      GPRINT:or at RRDIDX@:MIN:Min \: %5.1lf %s
      GPRINT:or at RRDIDX@:MAX:Max \: %5.1lf %s
      GPRINT:or at RRDIDX@:AVERAGE:Avg \: %5.1lf %s
      GPRINT:or at RRDIDX@:LAST:Cur \: %5.1lf %s\n

The web page of this test shows the two tables, but no graphs. Only the 
magnifying glasses, which should be on the right of a graph, are shown. 
When clicking on the magnifying glass, an empty page is shown. The source 
code of this page is two lines long, the first one specifying the title to 
be "Invalid request", the second on showing an empty body.

Removing the graph definition results in a link to be displayed, and the 
magnifying glass shows an appropriate error message. Further experiments 
showed that if all multi-graph stuff is removed (that is, FNPATTERN and the 
@RRD...@ parameters) a single graph is shown. Extending the graph 
definition with FNPATTERN causes to problem to surface again.

The logfiles of xymon do not contain messages related to this problem, as 
far as I can see. Enabling debugging for xymond_rrd, the one spawn by the 
status channel reader, does not give any helpful information.

All the other graphs, including one multi-graph (test memory), of this host 
are displayed. The problem is only visible in test odr_mux.

Can anyone give me a hint on how to proceed to solve this issue?

Regards,
    Wim Nelis.