Adds new REST API v2/

Addresses #5269

scripts/lua/rest/v2/get/datasource/interface/packet_distro.lua

@@ -0,0 +1,81 @@
+--
+-- (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"
+-- This is the datamodel used to represent data associated with this datasource
+local slices = require "slices"
+-- Rest utilities
+local rest_utils = require "rest_utils"
+
+-- ##############################################
+
+local packet_distro = classes.class(slices)
+
+-- ##############################################
+
+packet_distro.meta = {
+   params = {
+      -- NOTE: Specify all the parameter keys that must be passed in the request
+       "ifid" -- validated according to http_lint.lua
+   },
+}
+
+-- ##############################################
+
+-- Human-friendly labels for the distribution
+local available_bins = {
+   { key = 'upTo64',    label = '<= 64'        },
+   { key = 'upTo128',   label = '64 <= 128'    },
+   { key = 'upTo256',   label = '128 <= 256'   },
+   { key = 'upTo512',   label = '256 <= 512'   },
+   { key = 'upTo1024',  label = '512 <= 1024'  },
+   { key = 'upTo1518',  label = '1024 <= 1518' },
+   { key = 'upTo2500',  label = '1518 <= 2500' },
+   { key = 'upTo6500',  label = '2500 <= 6500' },
+   { key = 'upTo9000',  label = '6500 <= 9000' },
+   { key = 'above9000', label = '> 9000'       },
+}
+
+-- ##############################################
+
+-- @brief Datasource constructor
+function packet_distro:init()
+   -- Initializes parent class slices
+   self.super:init(10 --[[ Maximum number of slices ]],
+		   3 --[[ Percentage under which the slice is ignored and added to other --]])
+end
+
+-- #######################################################
+
+function packet_distro:fetch()
+   -- Assumes all parameters listed in self.meta.params have been parsed successfully
+   -- and are available in self.parsed_params
+
+   interface.select(tostring(self.parsed_params.ifid))
+   local ifstats = interface.getStats()
+   local size_bins = ifstats["pktSizeDistribution"]["size"]
+
+   self:set_label(getHumanReadableInterfaceName(getInterfaceName(ifstats.id)))
+   for _, bin in ipairs(available_bins) do
+      self:append(bin.label, size_bins[bin.key] or 0)
+   end
+end
+
+-- #######################################################
+
+-- Checks if this module is being loaded as part of a REST request to this endpoint or not.
+-- If the module is being loaded as part of a REST request, then a response is sent, otherwise nothing is done.
+-- Must call this to ensure REST responses are sent when necessary
+packet_distro:new():rest_send_response()
+
+-- #######################################################
+
+return packet_distro