gistfile1.txt

require "string"
os = require "os"
alert = require "alert"

local alert_threshold      = read_config("alert_threshold") or 5
local alert_throttle_time  = read_config("alert_throttle_time") or 300
local nanosecondsInASecond = 1000000000

alert.set_throttle(alert_throttle_time * nanosecondsInASecond)

function process_message ()
    local buffers     = read_message("Fields[Buffers]")
    local cached      = read_message("Fields[Cached]")
    local memFree     = read_message("Fields[MemFree]")
    local memTotal    = read_message("Fields[MemTotal]")
    local pctMemFree  = ((buffers + cached + memFree) / memTotal) * 100

    local host        = read_message("Hostname")
    local currentTime = os.time() * nanosecondsInASecond

    if pctMemFree < alert_threshold and not alert.throttled(currentTime) then
        local payload = string.format("Low Memory on %s, only %d percent free", host, pctMemFree)
        alert.send(currentTime, payload)
    end

    return 0
end

function timer_event(ns)
end