-- Export statistics in OpenMetrics format

--

-- Copyright (C) 2014 Daurnimator

-- Copyright (C) 2018 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>

-- Copyright (C) 2021 Jonas Schäfer <jonas@zombofant.net>

--

-- This module is MIT/X11 licensed.

module:set_global();

local statsman = require "prosody.core.statsmanager";

local ip = require "prosody.util.ip";

local get_metric_registry = statsman.get_metric_registry;

local collect = statsman.collect;

local get_metrics;

local permitted_ips = module:get_option_set("openmetrics_allow_ips", { "::1", "127.0.0.1" });

local permitted_cidr = module:get_option_string("openmetrics_allow_cidr");

local function is_permitted(request)

	local ip_raw = request.ip;

	if permitted_ips:contains(ip_raw) or

	   (permitted_cidr and ip.match(ip.new_ip(ip_raw), ip.parse_cidr(permitted_cidr))) then

		return true;

	end

	return false;

end

function get_metrics(event)

	if not is_permitted(event.request) then

		return 403; -- Forbidden

	end

	local response = event.response;

	response.headers.content_type = "application/openmetrics-text; version=0.0.4";

	if collect then

		-- Ensure to get up-to-date samples when running in manual mode

		collect()

	end

	local registry = get_metric_registry()

	if registry == nil then

		response.headers.content_type = "text/plain; charset=utf-8"

		response.status_code = 404

		return "No statistics provider configured\n"

	end

	return registry:render();

end

module:depends "http";

module:provides("http", {

	default_path = "metrics";

	route = {

		GET = get_metrics;

	};

});