Graph the max value rather than avg if rrdsingle disabled

With rrdsingle the average values are used for graphing. As the
timescale increases (say over a day or month) the average values
progressively reduce.  Using the maximum value over the longer periods
is arguably no less deceptive but it does produce more informative
graphs.

V2 - Invert the default path logic related to rra.single

Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
(cherry picked from commit f960a5286896aacbd95a7b95aa367d1584106b2b)

diff --git a/applications/luci-app-statistics/luasrc/statistics/rrdtool.lua b/applications/luci-app-statistics/luasrc/statistics/rrdtool.lua
index 5d4ad98..cd2395e 100644 (file)
--- a/applications/luci-app-statistics/luasrc/statistics/rrdtool.lua
+++ b/applications/luci-app-statistics/luasrc/statistics/rrdtool.lua
@@ -171,16 +171,29 @@ function Graph._generic( self, opts, plugin, plugin_instance, dtype, index )
 
                -- is first source in stack or overlay source: source_stk = source_nnl
                if not prev or source.overlay then
+                    if self.opts.rrasingle then
                        -- create cdef statement for cumulative stack (no NaNs) and also
                         -- for display (preserving NaN where no points should be displayed)
                        _tif( _args, "CDEF:%s_stk=%s_nnl", source.sname, source.sname )
                        _tif( _args, "CDEF:%s_plot=%s_avg", source.sname, source.sname )
+                    else
+                       -- create cdef statement for cumulative stack (no NaNs) and also
+                        -- for display (preserving NaN where no points should be displayed)
+                       _tif( _args, "CDEF:%s_stk=%s_nnl", source.sname, source.sname )
+                       _tif( _args, "CDEF:%s_plot=%s_max", source.sname, source.sname )
+                    end
 
                -- is subsequent source without overlay: source_stk = source_nnl + previous_stk
                else
+                    if self.opts.rrasingle then
                        -- create cdef statement
                        _tif( _args, "CDEF:%s_stk=%s_nnl,%s_stk,+", source.sname, source.sname, prev )
                        _tif( _args, "CDEF:%s_plot=%s_avg,%s_stk,+", source.sname, source.sname, prev )
+                    else
+                       -- create cdef statement
+                       _tif( _args, "CDEF:%s_stk=%s_nnl,%s_stk,+", source.sname, source.sname, prev )
+                       _tif( _args, "CDEF:%s_plot=%s_max,%s_stk,+", source.sname, source.sname, prev )
+                    end
                end
 
                -- create multiply by minus one cdef if flip is enabled