OpenWrt temperature monitor for prometheus-collectors

temp.lua

--[[
function print_metric(metric, labels, value)
  local label_string = ""
  if labels then
    for label,value in pairs(labels) do
      label_string =  label_string .. label .. '="' .. value .. '",'
    end
    label_string = "{" .. string.sub(label_string, 1, -2) .. "}"
  end
  io.write(string.format("%s%s %s", metric, label_string, value))
end

function metric(name, mtype, labels, value)
  local outputter = function(labels, value)
    print_metric(name, labels, value)
  end
  if value then
    outputter(labels, value)
  end
  return outputter
end
--]]

local function scrape()
	local json = require "luci.jsonc"
	local fs   = require "nixio.fs"

	local sysHwmon   = "/sys/class/hwmon"
	local sysThermal = "/sys/class/thermal"

	local function readFile(path)
		local s = fs.readfile(path)
		return s and (s:gsub("^%s+", ""):gsub("%s+$", ""))
	end

	local function list()
		io.write('{"getTempStatus":{}}')
	end

	local temp_metric = metric("sensor_temperature", "gauge")
	-- /sys/class/hwmon
	local hwmonDir = fs.dir(sysHwmon)
	if hwmonDir then
		local hwmon = {}
		for item in hwmonDir do
			if item:match("^hwmon[0-9]+$") then
				local deviceDirPath = string.format("%s/%s", sysHwmon, item)
				local deviceDir     = fs.dir(deviceDirPath)
				if deviceDir then
					local dNumber = tonumber(item:match("[0-9]+"))
					local title   = readFile(deviceDirPath .. "/name")
					for source in deviceDir do
						if source:match("^temp[0-9]+_input$") then
							local sNumber = tonumber(source:match("[0-9]+"))
							local temp    = readFile(
								string.format("%s/%s", deviceDirPath, source))
-- 							local label   = readFile(
-- 								string.format("%s/%s", deviceDirPath, source:gsub("_input$", "_label")))
							if sNumber ~= nil and temp ~= nil then
								temp_metric({name="hwmon_"..title..sNumber}, tonumber(temp))
							end
						end
					end
				end
			end
		end
	end
	-- /sys/class/thermal
	local dir   = fs.dir(sysThermal)
	if dir then
		for item in dir do
			if item:match("^thermal_zone[0-9]+$") then
				local number = tonumber(item:match("[0-9]+"))
				local temp   = readFile(string.format("%s/%s/temp", sysThermal, item))
				local title  = readFile(string.format("%s/%s/type", sysThermal, item))
				if number ~= nil and temp ~= nil then
					temp_metric({name=title..number}, tonumber(temp))
				end
			end
		end
	end
end

-- scrape()

return { scrape = scrape }