File

util/watchdog.lua @ 11593:0db763f3f3be

util.openmetrics: Prettify format of histogram buckets "%g" turns 1GB into 1.07374e+09, which is a bit awkward for the bytes measurements IMO. Turning up the precision, at "%.17g" turns 0.1 into 0.10000000000000001 while "%0.16" gives 0.1, hiding most of those pesky floating point artefacts. Lua version 5.2 uses "%.14g" ( see LUA_NUMBER_FMT in luaconf.h.html ) so it seems like a sensible choice here.
author Kim Alvefur <zash@zash.se>
date Tue, 08 Jun 2021 00:58:27 +0200
parent 8555:4f0f5b49bb03
child 12545:5059a639f61e
line wrap: on
line source

local timer = require "util.timer";
local setmetatable = setmetatable;
local os_time = os.time;

local _ENV = nil;
-- luacheck: std none

local watchdog_methods = {};
local watchdog_mt = { __index = watchdog_methods };

local function new(timeout, callback)
	local watchdog = setmetatable({ timeout = timeout, last_reset = os_time(), callback = callback }, watchdog_mt);
	timer.add_task(timeout+1, function (current_time)
		local last_reset = watchdog.last_reset;
		if not last_reset then
			return;
		end
		local time_left = (last_reset + timeout) - current_time;
		if time_left < 0 then
			return watchdog:callback();
		end
		return time_left + 1;
	end);
	return watchdog;
end

function watchdog_methods:reset()
	self.last_reset = os_time();
end

function watchdog_methods:cancel()
	self.last_reset = nil;
end

return {
	new = new;
};