util/throttle.lua
author Kim Alvefur <zash@zash.se>
Wed, 27 Mar 2024 19:33:11 +0100
changeset 13471 c2a476f4712a
parent 12979 d10957394a3c
permissions -rw-r--r--
util.startup: Fix exiting on pidfile trouble prosody.shutdown() relies on prosody.main_thread, which has not been set yet at this point. Doing a clean shutdown might actually be harmful in case it tears down things set up by the conflicting Prosody, such as the very pidfile we were looking at. Thanks again SigmaTel71 for noticing


local gettime = require "prosody.util.time".now
local setmetatable = setmetatable;

local _ENV = nil;
-- luacheck: std none

local throttle = {};
local throttle_mt = { __index = throttle };

function throttle:update()
	local newt = gettime();
	local elapsed = newt - self.t;
	self.t = newt;
	local balance = (self.rate * elapsed) + self.balance;
	if balance > self.max then
		self.balance = self.max;
	else
		self.balance = balance;
	end
	return self.balance;
end

function throttle:peek(cost)
	cost = cost or 1;
	return self.balance >= cost or self:update() >= cost;
end

function throttle:poll(cost, split)
	if self:peek(cost) then
		self.balance = self.balance - cost;
		return true;
	else
		local balance = self.balance;
		if split then
			self.balance = 0;
		end
		return false, balance, (cost-balance);
	end
end

local function create(max, period)
	return setmetatable({ rate = max / period, max = max, t = gettime(), balance = max }, throttle_mt);
end

return {
	create = create;
};