NAME

       Smokeping::sorters::base - Base Class for implementing SmokePing Sorters

OVERVIEW

       Sorters are at the core of the SmokePing Charts feature, where the most interesting graphs
       are presented on a single page. The Sorter decides which graphs are considerd interesting.

       Every sorter must inherit from the base class and provide it's own methods for the
       'business' logic.

       In order to maintain a decent performance the sorters activity is split into two parts.

       The first part is active while the smokeping daemon gathers its data.  Whenever data is
       received, the sorter is called to calculate a 'value' for the present data. On every
       'query round' this information is stored in the sorter store directory. Each smokeping
       process stores it's own information.  Since smokeping can run in multiple instances at the
       same time, the data may be split over several files

       The second part of the sorter is called from smokeping.cgi. It loads all the information
       from the sorter store and integrates it into a single 'tree'. It then calls each sorter
       with the pre-calculated data to get it sorted and to and to select the interesting
       information.

DESCRIPTION

       Every sorter must provide the following methods:

   new
       The new method expects hash elements as an argument eg new({x=>'\d+',y=>'\d+'},x=>1,y=>2).
       The first part is a syntax rule for the arguments it should expect and the second part are
       the arguments itself. The first part will be supplied by the child class as it calls the
       parent method.

   Desc
       Simply return the description of the function. This method must be overwritten by a
       children of the base class.

   SortTree
       Returns an array of 'targets'. It is up to the sorter to decide how many entries the list
       should contain. If the list is empty, the whole entry will be supressed in the
       webfrontend.

       The methode gets access to all the targets in the system, together with the last data set
       acquired for each target.

   CalcValues
       Figure out the curent sorting value using te following input.

        $info = { uptime => w,
                  loss   => x,
                  median => y,
                  alert  => z, # (0/1)
                  pings  => [qw(a b c d)] }

       The output can have any structure you want. It will be returned to the sorter method for
       further processng.

COPYRIGHT

       Copyright (c) 2007 by OETIKER+PARTNER AG. All rights reserved.

LICENSE

       This program is free software; you can redistribute it and/or modify it under the terms of
       the GNU General Public License as published by the Free Software Foundation; either
       version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
       without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
       See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program;
       if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
       USA.

AUTHOR

       Tobias Oetiker <tobi@oetiker.ch>