Merge lp:~cody-stevens/graphite/graphite into lp:graphite

[Cody Stevens]

Graphite usually treats 'None' values as missing data which results in breaks in the lines of the graph. However, the sum and diff functions will basically treat them as a 0 value which can make the graph inaccurate when adding or diffing 2 series. This update checks to make sure that there are at least 2 values to be summed or diffed and if not will not do the diff/sum. This falls more in line with the way that graphite handles 'None' values IMHO.

[Sidnei da Silva (sidnei)]

Hi Cody,

Graphite's development has now moved to github (https://github.com/graphite-project/graphite-web), please submit your pull request there instead.

Unmerged revisions

865. By Cody Stevens on 2012-10-31

Updated safeDiff and safeSum to require 2 values to be summed/diffed.

=== modified file 'webapp/graphite/render/functions.py'
--- webapp/graphite/render/functions.py	2012-10-16 01:41:01 +0000
+++ webapp/graphite/render/functions.py	2012-10-31 17:01:24 +0000
@@ -46,12 +46,12 @@
 #Utility functions
 def safeSum(values):
   safeValues = [v for v in values if v is not None]
-  if safeValues:
+  if safeValues and len(safeValues) > 1:
     return sum(safeValues)
 
 def safeDiff(values):
   safeValues = [v for v in values if v is not None]
-  if safeValues:
+  if safeValues and len(safeValues) > 1:
     values = map(lambda x: x*-1, safeValues[1:])
     values.insert(0, safeValues[0])
     return sum(values)