Implements ability to consolidate widgets (slices and values)

scripts/lua/modules/datamodel/slices.lua

@@ -0,0 +1,96 @@
+--
+-- (C) 2019-21 - ntop.org
+--
+
+local dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
+package.path = dirs.installdir .. "/scripts/lua/modules/datamodel/?.lua;" .. package.path
+
+-- ##############################################
+
+-- Import the classes library.
+local classes = require "classes"
+-- Import the base class
+local datamodel = require "datamodel"
+
+-- ##############################################
+
+local slices = classes.class(datamodel)
+
+-- ##############################################
+
+slices.meta = {
+   -- Default values
+   max_num_slices      = 10, -- Maximum number of slices handled
+   other_threshold_pct = 3,  -- Percentage under which the slice is ignored and value added to a slice 'other'
+}
+
+-- ##############################################
+
+-- @brief Datasource constructor
+function slices:init(labels, max_num_slices, other_threshold_pct)
+   -- Call the parent constructor
+   self.super:init(labels)
+
+   if max_num_slices then
+      self.meta.max_num_slices = max_num_slices
+   end
+
+   if other_threshold_pct then
+      self.meta.other_threshold_pct = other_threshold_pct
+   end
+end
+
+-- #######################################################
+
+-- @brief Consolidates `append`ed data, enforcing `max_num_slices` and `other_threshold_pct`
+--        OVERRIDE
+function slices:consolidate()
+   local consolidated = {}
+   local total_value = 0
+   local cur_slice = 1
+
+   -- Compute the total
+   for slice_key, slice in pairs(self._data) do
+      total_value = total_value + slice.v
+   end
+
+   -- Sort by descending `v`alue of slice
+   for slice_key, slice in pairsByField(self._data, 'v', rev) do
+      if cur_slice < self.meta.max_num_slices and slice.v / total_value * 100 > self.meta.other_threshold_pct then
+	 -- Preserve this slice
+	 consolidated[slice_key] = slice
+      else
+	 -- Start adding to the 'other' slice
+	 if not consolidated.other then
+	    consolidated.other = slice
+	    consolidated.other.k = 'other'
+	 else
+	    -- Sum the current `other` value with the value for this slice
+	    consolidated.other.v = consolidated.other.v + slice.v
+	 end
+      end
+
+      cur_slice = cur_slice + 1
+   end
+
+   self._data = consolidated
+end
+
+-- #######################################################
+
+-- @brief Returns (possibly consolidated) data
+function slices:get_data()
+   local res = {}
+
+   -- Returns data sorted according to keys
+   for slice_key, slice in pairsByKeys(self._data, asc) do
+      res[#res + 1] = slice
+   end
+
+   return res
+end
+
+-- #######################################################
+
+return slices