[rrd-users] newbie perl problem with rrds::graph

[Mark Wingate]

Here are a few ideas that should get you closer.  I haven't used RRDs::graph, so I may be doing something silly with the quoting.


 &CreateGraph("$computer", "day", $harddrives); # I removed a double quote before $harddrives
 &CreateGraph("$computer", "week", $harddrives); # ditto

 # let's assume you have a string containing hard drive names, like this: $harddrives = "hda hdb hdc"

sub CreateGraph
  {
  # creates graph
  # inputs: $_[0]: computer id
  #         $_[1]: interval (ie, day, week, month, year)
  #         $_[2]: hard drive names for computer (ie, hda, hdb, hdc)

  ( $computer_id, $interval, $hd_list ) = @_;  # treat yourself and others to some human-readable variables!

  #$size = scalar @_;  # get total amount of parameters  <-- not needed
  @defs = (); #<-- use array to gather up the defs
  @graphs = (); #<-- ... and the graph specs

  for $drive ( split(' ', $hd_list ) {
      push @defs, "DEF:$drive=$rrd/$drive.rrd:temp:AVERAGE";

      # -- while troubleshooting, I would make the GPRINTs as simple as possible.
      push @graphs,  "LINE2:$drive#FF9900:$drive\\: ",
                     "GPRINT:$drive:MIN:  Min\\: %2.lf ",
                     "GPRINT:$drive:MAX: Max\\: %2.lf ",
                     "GPRINT:$drive:AVERAGE: Avg\\: %4.1lf ",
                     "GPRINT:$drive:LAST: Current\\: %2.lf degrees C\\n ";
      }

      RRDs::graph "$img/$computer_id/hddtemp-$interval.png",
              "--lazy",
              "-s -1$interval",
              "-t 'hdd temperature :: hard disk drives'", #<-- added some quotes
              "-h", "80", "-w", "600",
              "-a", "PNG",
              "-v 'degrees C'",  #<-- added some quotes
              "--slope-mode",
              join(' ', @defs),
              join(' ', @graphs);

      if ( = RRDs::error) { print "$0: unable to generate $interval graph:
$ERROR\n"; }
  }

  #... If you put the hard drives into an array instead of building a string,
  #you would do something like this:

  #Let's say @harddrives contains the drive names;
  @harddrives = ('hda', 'hdb', 'hdc');  # Perl-y way: ... = qw(hda hdb hdc);

  #But don't pass the array in, pass a reference instead ...
  &CreateGraph("$computer", "day", \@harddrives); # removed a ouble quote before $harddrives

  #Then change the routine to use the ref
  ( $computer_id, $interval, $hd_list_ref ) = @_;  # changing variable name just for clarity
  #...
  for $drive ( @$hd_list_ref ) {
  #... that's it.


Mark Wingate