[collectd] collection4 nitpicking

[Trent W. Buck]

Trent W. Buck wrote:
> So I added these two.  The first works fine, the second gives strange
> results because each line should pick up $TypeInstance, which will be
> "error", "loop", or an IP address I don't know in advance.  I haven't
> worked out how to add a "dynamic" set of <DEF>s, i.e. have it
> automatically label the lines like "128.16.0.1" instead of "value3".

Looks like this comes from def_get_rrdargs():

    if ((legend[0] == 0) || (strcmp ("default", legend) == 0))
    {
      strncpy (legend, def->ds_name, sizeof (legend));
      legend[sizeof (legend) - 1] = 0;
    }

I think there should be some way to ask at the graph level for it to
use (I think) def->type_instance instead of def->ds_name, so
e.g. you'd do that for NFS, but not for... something with different
values within a single type_instance.

BTW, I notice the graph list is unsorted; entries appear as they are
listed in the config file.  Not sure if this is by design, but might
be useful to have them sorted instead/optionally.