view mod_measure_process/mod_measure_process.lua @ 5668:ecfd7aece33b

mod_measure_modules: Report module statuses via OpenMetrics Someone in the chat asked about a health check endpoint, which reminded me of mod_http_status, which provides access to module statuses with full details. After that, this idea came about, which seems natural. As noted in the README, it could be used to monitor that critical modules are in fact loaded correctly. As more modules use the status API, the more useful this module and mod_http_status becomes.
author Kim Alvefur <zash@zash.se>
date Fri, 06 Oct 2023 18:34:39 +0200
parents c26f515751af
children
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module:set_global()

local get_cpu_time = os.clock

local custom_metric = require "core.statsmanager".metric
local cpu_time = custom_metric(
	"counter", "process_cpu", "seconds",
	"CPU time used by Prosody as reported by clock(3)."
):with_labels()

local lfs = require "lfs"

module:hook("stats-update", function ()
	cpu_time:set(get_cpu_time())
end);

if lfs.attributes("/proc/self/statm", "mode") == "file" then
	local pagesize = module:get_option_number("memory_pagesize", 4096); -- getconf PAGESIZE

	local vsz = custom_metric(
		"gauge", "process_virtual_memory", "bytes",
		"Virtual memory size in bytes."
	):with_labels()
	local rss = custom_metric(
		"gauge", "process_resident_memory", "bytes",
		"Resident memory size in bytes."
	):with_labels()

	module:hook("stats-update", function ()
		local statm, err = io.open("/proc/self/statm");
		if not statm then
			module:log("error", tostring(err));
			return;
		end
		-- virtual memory (caches, opened librarys, everything)
		vsz:set(statm:read("*n") * pagesize);
		-- resident set size (actually used memory)
		rss:set(statm:read("*n") * pagesize);
		statm:close();
	end);
end

if lfs.attributes("/proc/self/fd", "mode") == "directory" then
	local open_fds = custom_metric(
		"gauge", "process_open_fds", "",
		"Number of open file descriptors."
	):with_labels()

	local has_posix, posix = pcall(require, "util.pposix")
	local max_fds
	if has_posix then
		max_fds = custom_metric(
			"gauge", "process_max_fds", "",
			"Maximum number of open file descriptors"
		):with_labels()
	else
		module:log("warn", "not reporting maximum number of file descriptors because mod_posix is not available")
	end

	local function limit2num(limit)
		if limit == "unlimited" then
			return math.huge
		end
		return limit
	end

	module:hook("stats-update", function ()
		local count = 0
		for _ in lfs.dir("/proc/self/fd") do
			count = count + 1
		end
		open_fds:set(count)

		if has_posix then
			local ok, soft, hard = posix.getrlimit("NOFILE")
			if ok then
				max_fds:set(limit2num(soft or hard));
			end
		end
	end);
end