AN25 IP WatchDog 2 from 10 – list of monitored devices, failure indication by power output (Lua script)

2) Fill in the following parameters:

• Enabled: checked
• Name: IP Watchdog 1 from 10 (user-defined)
• Description: Watchdog for 10 IP devices (user-defined)
• Trigger: System started up
• Schedule: Always

3) Copy the following code and paste it into the field for the Lua script:

 
------------NETIO AN25------------

------------Section 1------------
local IPs = -- Watched IP addresses
{
"192.168.101.185",
"192.168.101.136",
"192.168.1.155",
"192.168.1.25",
"192.168.0.36",
"192.168.2.56"  
}

local period = 5 -- period between pings [s]
local disconectedIPs = 1 -- number of maximum disconnected IP addresses
local maxMissedCycles = 2 -- number of maximum missed ping cycles
local controlOutput = 1 -- output for signalization (1-4)
local actionOK = 1 -- number of action for OK state (0-5)
local actionNoOK = 4 -- number of action for no OK state (0-5)
local periodAction = 1 -- periodical execution of actionNoOK (0/1)
local shortTimeMs = 2000 -- time for actions 2 and 3 [ms]
---------End of Section 1---------

local iterator = 1
local deadIPs = {}
local missedCycles = 0
local actionExecuted = false

function doAction()
  log("Doing NO OK action")
  setOutput(controlOutput,actionNoOK)
end

function doOKAction()
  log("Doing OK action")
  setOutput(controlOutput,actionOK)
end


function setOutput(output,action)
  if action == 0 then -- turn off
    devices.system.SetOut{output = output, value = false}
  elseif action == 1 then -- turn on
    devices.system.SetOut{output = output, value = true}
  elseif action == 2 then -- short off
    devices.system.SetOut{output = output, value = false}
    milliDelay(shortTimeMs,function() short(output,true) end)
  elseif action == 3 then -- short on
    devices.system.SetOut{output = output, value = true}
    milliDelay(shortTimeMs,function() short(output,false) end)   
  elseif action == 4 then -- toggle
    if devices.system["output" ..output.. "_state"] == 'on' then 
      devices.system.SetOut{output=output,value=false}
    else
      devices.system.SetOut{output=output, value=true}
    end
  elseif action == 5 then
    -- do nothing
  end
end


function pingIP()
  local IP = IPs[iterator]
  ping{address=IP, timeout=5, callback=checkResult}
end

function checkResult(o)
  if not o.success then
    logf("IP:%s is not OK",IPs[iterator])
    table.insert(deadIPs, IPs[iterator]) 
  end
  if iterator == #IPs then
    log("Last IP, checking dead IPs")
    checkCounters()
  end
  iterator = (iterator)%#IPs + 1
  delay(period,function() pingIP() end)
end  


function checkCounters()
  local reportString = "{"
  for i=1,#deadIPs,1 do 
    reportString = reportString .. deadIPs[i]
    if i<#deadIPs then
      reportString = reportString .. ", "
    end
  end
  reportString = reportString .. "}"
  logf("Dead IPs : %d - " .. reportString,#deadIPs)
  if #deadIPs >= disconectedIPs then
    log("Number of dead IPs exceeded limit.")
    missedCycles = missedCycles + 1
    logf("Missed cycles: %d/%d",missedCycles,maxMissedCycles)
    if missedCycles >= maxMissedCycles then
      log("Missed cycles limit exceeded")
      if (not actionExecuted) or (toboolean(periodAction)) then
        actionExecuted = true
        doAction()
      end
    end
  else
    missedCycles = 0
    if actionExecuted then
      log("Number of disconnected IPs is now in limit, excecuting OK action")
      actionExecuted = false
      doOKAction()
    end
  end
  deadIPs = {}
end

pingIP()

4) To finish creating the rule, click Create Rule at the bottom of the screen.

Setting the variables

• IPs
  • A table of strings containing the monitored IP addresses.
  • The table starts and begins with curly braces, individual IPs must be enclosed in double quotes and separated with commas.
  • Instead of the IPs, DNS names can be also specified (e.g. "www.google.com"); however, in case of a DNS server failure, the device will be considered unresponsive even if it works OK.
     
  • Example with 10 different IP addresses:

local IPs = {

"192.168.101.186",

"192.168.101.3",

"192.168.101.21",

"22.128.12.252",

"157.25.2.5",

"32.21.51.32",

"51.211.56.25",

"128.11.18.8",

"135.51.18.105",

"143.38.15.202" 

}

• period
  • This variable sets the time between the successive ping checks of individual IP addresses (in seconds).
  • The minimum value is 1.
  • When the period is set to 5 seconds and there are 10 IPs, all IPs will be checked in 50 seconds (that is the duration of one cycle).
  • Example – to set the period to 5 seconds: period = 5
     
• disconectedIPs
  • Minimum number of non-responding IP addresses to trigger the action.
  • Example – to trigger the action when 2 or more IPs keep failing to respond during a certain time: disconectedIPs = 2
     
• maxMissedCycles
  • The maximum tolerated number of successive cycles during which at least disconectedIPs addresses are unresponsive. If the number of cycles exceeds this threshold, actionNoOK is invoked.
  • Example – to trigger the action after more than 4 cycles of unavailability: maxMissedCycles = 4 (4 is the maximum number of cycles before triggering the action; therefore, the action will be triggered in the 5th cycle, as long as the specified number of IPs is still unreachable)
     
• controlOutput
  • Specifies the controlled output that is used to signal failures (1 to 4).
  • Example – to specify output no. 2: controlOutput = 2
     
• actionOK
  • Specifies the action to perform with the controlled output if the number of unresponsive IPs drops below the disconectedIPs threshold.
  • Actions:
    •  0 – output switched off
    •  1 – output switched on
    •  2 – “short off”, output is set to 0, and after a delay specified in the shortTimeMs variable, the output is set to 1
    •  3 – “short on”, output is set to 1, and after a delay specified in the shortTimeMs variable, the output is set to 0
    •  4 – “toggle”, if the output was on, it is turned off, and vice versa
       
• actionNoOK
  • Specifies the action to perform with the controlled output if the number of unresponsive IPs reaches the disconectedIPs threshold.
  • The action numbers are the same as for actionOK.
     
• periodAction
  • Specifies whether actionNoOK is performed in every cycle after the maxMissedCycles threshold is exceeded, or only once.
     
• shortTimeMs
  •  Specifies (in milliseconds) for how long the output stays off or on for actions 2 and 3 respectively.
  •  The minimum value is 100 ms.
  •  Example – for 2 seconds between state changes: shortTimeMs = 2000

Starting the script

After configuring all the parameters and saving the script, the NETIO 4x smart sockets device needs to be restarted. After the device reboots, the script is started and the accessibility of the defined IP addresses begins to be checked.

The log will contain:

• Failure of a device, with a timestamp
• Alarm activation (output turned on / off)
• Number of unresponsive IPs at a given time

FAQ:

1) Is it possible to monitor more than 10 IP addresses?

Yes, the IPs variable can contain as many IP addresses as needed. The 10 IPs are chosen as an example. Having more IPs extends the reaction time; allow for 3-5 seconds per IP address for the check.

2) Is it possible to send an e-mail in response to an outage?

Of course; however, e-mail must be correctly configured in the Settings - Email section. Then, insert the following command into the doAction() or doOKAction() function (depending on when the e-mail should be sent):

mail("my.email@gmail.com","NETIO IP Watchdog","Too many disconnected IP addresses")

3) Where can I see which device out of the 10 monitored devices has failed?

Information about unresponsive devices is recorded in the device log.

4) Why check for failure of exactly 2 out of 10 devices?

This is just an example; the number of devices can be set in the disconectedIPs variable.

Supported FW versions:

3.0.0 and higher (Firmware archive)

More about Lua:

https://wiki.netio-products.com