ntopng/scripts/callbacks/interface/alerts/interface.lua
2019-07-08 11:08:45 +02:00

127 lines
4.3 KiB
Lua

--
-- (C) 2019 - ntop.org
--
local dirs = ntop.getDirs()
package.path = dirs.installdir .. "/scripts/lua/modules/?.lua;" .. package.path
require "lua_utils"
require "alert_utils"
alerts_api = require("alerts_api")
local do_trace = true
local config_alerts = nil
local ifname = nil
-- The function below ia called once (#pragma once)
function setup(str_granularity)
print("alert.lua:setup("..str_granularity..") called\n")
ifname = interface.setActiveInterfaceId(tonumber(interface.getId()))
config_alerts = getInterfaceConfiguredAlertThresholds(ifname, str_granularity)
end
-- #################################################################
function bytes(metric_name, info, granularity)
local key = metric_name..":"..granularity
local prev_bytes = interface.getCachedAlertValue(key) -- read cached value
local curr_bytes = info["stats"]["bytes"]
local diff
-- tprint(info)
-- purify the value
if(prev_bytes == "") then prev_bytes = 0 else prev_bytes = tonumber(prev_bytes) end
-- save the value for the next round
interface.setCachedAlertValue(key, tostring(curr_bytes))
-- compute the difference
return(curr_bytes - prev_bytes)
end
-- #################################################################
-- The function below is called once per interface
local function checkInterfaceAlertsThreshold(interface_key, interface_info, granularity, rules)
if(do_trace) then print("checkInterfaceAlertsThreshold()\n") end
for function_name,params in pairs(rules) do
-- IMPORTANT: do not use "local" with the variables below
-- as they need to be accessible by the evaluated function
threshold_value = params["edge"]
alert_key_name = params["key"]
threshold_operator = params["operator"]
metric_name = params["metric"]
threshold_gran = granularity
i_info = interface_info
print("[Alert @ "..granularity.."] ".. interface_key .." ["..function_name.."]\n")
if(true) then
-- This is where magic happens: load() evaluates the string
local what = 'return('..function_name..'(metric_name, i_info, threshold_gran))'
-- print(what)
local func, err = load(what)
if func then
local ok, value = pcall(func)
if ok then
local alarmed = false
local interface_alert = alerts_api:newAlert({ entity = "host", type = "threshold_cross", severity = "error" })
if(do_trace) then print("Execution OK. value: "..tostring(value)..", operator: "..threshold_operator..", threshold: "..threshold_value.."]\n") end
threshold_value = tonumber(threshold_value)
if(threshold_operator == "lt") then
if(value < threshold_value) then alarmed = true end
else
if(value > threshold_value) then alarmed = true end
end
if(alarmed) then
print("Trigger alert [value: "..tostring(value).."]\n")
-- IMPORTANT: uncommenting the line below break all
-- interface_alert:trigger(interface_key, "Host "..interface_key.." crossed threshold "..metric_name)
host.storeTriggeredAlert(alert_key_name..":"..granularity)
else
print("DON'T trigger alert [value: "..tostring(value).."]\n")
-- interface_alert:release(interface_key)
host.releaseTriggeredAlert(alert_key_name..":"..granularity)
end
else
if(do_trace) then print("Execution error: "..tostring(rc).."\n") end
end
else
print("Compilation error:", err)
end
end
print("=============\n")
end
end
-- #################################################################
-- The function below is called once per host
function checkInterfaceAlerts(granularity)
local info = interface.getStats()
local interface_key = "iface_"..interface.getId()
local interface_alert = config_alerts[interface_key]
if(do_trace) then print("checkInterfaceAlerts()\n") end
-- specific host alerts
if((interface_alert ~= nil) and (table.len(interface_alert) > 0)) then
checkInterfaceAlertsThreshold(interface_key, info, granularity, interface_alert)
end
-- generic host alerts
interface_alert = config_alerts["interfaces"]
if((interface_alert ~= nil) and (table.len(interface_alert) > 0)) then
checkInterfaceAlertsThreshold(interface_key, info, granularity, interface_alert)
end
end