Archive discovery, was Re: __pmDiscoverServices()/pmfind Enhancements

[fche@xxxxxxxxxx (Frank Ch. Eigler)]

Hi -

While hacking on pmwebd extensions, it occurred to me that we could
offer archive discovery capabilities within the pmDiscoverServices()
function.  This could be handy for interactive users to populate file
browsers or live web popups, and possibly for tools too.

It could look like this:

   pmDiscoverServices("archive", "...specs...", & urls);
   /* where urls[] might return file:///PATH/FOO.meta or /PATH/FOO.meta */

   /* find all .meta files under pwd */
   pmDiscoverServices("archive", "", & urls);
   pmDiscoverServices("archive", "basedir=.", & urls); /* equivalently */

Going wild with possible options:

 - search multiple directories
                                 "basedir=/PATH,basedir=/PATH2"
 - filter for archive-label matching given hostname
                                 ",loghost=BAR.BAZ"
 - filter for archive-label covering all given TIME(s)
                                 ",logtime=TIME,logtime=TIME"
 - filter for archive metadata including metric
                                 ",metric=PMNS"
 - limit directory recursion
                                 ",maxdepth=NN"
 - limit time
                                 ",timeout=NN"


- FChE