Add interfaces stats api and refactor the others health api. (#7141)

scripts/lua/rest/v2/get/system/health/stats.lua

@@ -0,0 +1,36 @@
+--
+-- (C) 2013-23 - ntop.org
+--
+
+local dirs = ntop.getDirs()
+package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
+
+require "lua_utils"
+local storage_utils = require("storage_utils")
+local cpu_utils = require("cpu_utils")
+local rest_utils = require("rest_utils")
+
+--
+-- Read system statistics
+-- Example: curl -u admin:admin -H "Content-Type: application/json" http://localhost:3000/lua/rest/v2/get/system/stats.lua
+--
+-- NOTE: in case of invalid login, no error is returned but redirected to login
+--
+
+if not isAllowedSystemInterface() then
+   rc = rest_utils.consts.err.not_granted
+   rest_utils.answer(rc)
+   return
+end
+
+local rc = rest_utils.consts.success.ok
+local res = cpu_utils.systemHostStats()
+res.epoch = os.time()
+res.storage = storage_utils.storageInfo()
+
+local info = ntop.getInfo()
+if(info.pid ~= nil) then
+   res.pid = info.pid
+end
+
+rest_utils.answer(rc, res)