Implemented skeleton of CustomFlowLuaScriptAlert check

scripts/lua/modules/alert_keys/flow_alert_keys.lua

@@ -93,7 +93,8 @@ local flow_alert_keys = {
    flow_alert_ndpi_http_obsolete_server            = 84,
    flow_alert_ndpi_risky_asn                       = 85,
    flow_alert_ndpi_risky_domain                    = 86,
-   
+   flow_alert_custom_lua_script                    = 87,
+
    -- NOTE: for flow alerts not not go beyond the size of Bitmap alert_map inside Flow.h (currently 128)
 }
 

scripts/lua/modules/check_definitions/flow/custom_lua_script.lua

@@ -0,0 +1,27 @@
+--
+-- (C) 2019-22 - ntop.org
+--
+
+local checks = require("checks")
+local flow_consts = require("flow_consts")
+local alerts_api = require "alerts_api"
+local alert_consts = require("alert_consts")
+local flow_alert_keys = require "flow_alert_keys"
+
+-- #################################################################
+
+local script = {
+   -- Script category
+   category = checks.check_categories.security, 
+
+   alert_id = flow_alert_keys.flow_alert_custom_lua_script,
+
+   gui = {
+      i18n_title = "flow_checks_config.custom_lua_script",
+      i18n_description = "flow_checks_config.custom_lua_script_description",
+   }
+}
+
+-- #################################################################
+
+return script

scripts/lua/modules/check_templates/multi_threshold_cross.lua

@@ -43,7 +43,9 @@ function multi_threshold_cross:describeConfig(hooks_conf)
   local msg = ''
 
   for field, value in pairs(configured_threshold) do
-    msg = msg .. i18n(field) .. ": " .. value.threshold .. "%, " 
+     if(value.threshold ~= nil) then
+	msg = msg .. i18n(field) .. ": " .. value.threshold .. "%, "
+     end
   end
 
   return msg