File

plugins/mod_posix.lua @ 11523:5f15ab7c6ae5

Statistics: Rewrite statistics backends to use OpenMetrics The metric subsystem of Prosody has had some shortcomings from the perspective of the current state-of-the-art in metric observability. The OpenMetrics standard [0] is a formalization of the data model (and serialization format) of the well-known and widely-used Prometheus [1] software stack. The previous stats subsystem of Prosody did not map well to that format (see e.g. [2] and [3]); the key reason is that it was trying to do too much math on its own ([2]) while lacking first-class support for "families" of metrics ([3]) and structured metric metadata (despite the `extra` argument to metrics, there was no standard way of representing common things like "tags" or "labels"). Even though OpenMetrics has grown from the Prometheus world of monitoring, it maps well to other popular monitoring stacks such as: - InfluxDB (labels can be mapped to tags and fields as necessary) - Carbon/Graphite (labels can be attached to the metric name with dot-separation) - StatsD (see graphite when assuming that graphite is used as backend, which is the default) The util.statsd module has been ported to use the OpenMetrics model as a proof of concept. An implementation which exposes the util.statistics backend data as Prometheus metrics is ready for publishing in prosody-modules (most likely as mod_openmetrics_prometheus to avoid breaking existing 0.11 deployments). At the same time, the previous measure()-based API had one major advantage: It is really simple and easy to use without requiring lots of knowledge about OpenMetrics or similar concepts. For that reason as well as compatibility with existing code, it is preserved and may even be extended in the future. However, code relying on the `stats-updated` event as well as `get_stats` from `statsmanager` will break because the data model has changed completely; in case of `stats-updated`, the code will simply not run (as the event was renamed in order to avoid conflicts); the `get_stats` function has been removed completely (so it will cause a traceback when it is attempted to be used). Note that the measure_*_event methods have been removed from the module API. I was unable to find any uses or documentation and thus deemed they should not be ported. Re-implementation is possible when necessary. [0]: https://openmetrics.io/ [1]: https://prometheus.io/ [2]: #959 [3]: #960
author Jonas Schäfer <jonas@wielicki.name>
date Sun, 18 Apr 2021 11:47:41 +0200
parent 11179:96da09c771a1
child 11830:7fe2fbfbdb1c
line wrap: on
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--


local want_pposix_version = "0.4.0";

local pposix = assert(require "util.pposix");
if pposix._VERSION ~= want_pposix_version then
	module:log("warn", "Unknown version (%s) of binary pposix module, expected %s."
		.. "Perhaps you need to recompile?", tostring(pposix._VERSION), want_pposix_version);
end

local have_signal, signal = pcall(require, "util.signal");
if not have_signal then
	module:log("warn", "Couldn't load signal library, won't respond to SIGTERM");
end

local lfs = require "lfs";
local stat = lfs.attributes;

local prosody = _G.prosody;

module:set_global(); -- we're a global module

local umask = module:get_option_string("umask", "027");
pposix.umask(umask);

-- Don't even think about it!
if not prosody.start_time then -- server-starting
	if pposix.getuid() == 0 and not module:get_option_boolean("run_as_root") then
		module:log("error", "Danger, Will Robinson! Prosody doesn't need to be run as root, so don't do it!");
		module:log("error", "For more information on running Prosody as root, see https://prosody.im/doc/root");
		prosody.shutdown("Refusing to run as root");
	end
end

local pidfile;
local pidfile_handle;

local function remove_pidfile()
	if pidfile_handle then
		pidfile_handle:close();
		os.remove(pidfile);
		pidfile, pidfile_handle = nil, nil;
	end
end

local function write_pidfile()
	if pidfile_handle then
		remove_pidfile();
	end
	pidfile = module:get_option_path("pidfile", nil, "data");
	if pidfile then
		local err;
		local mode = stat(pidfile) and "r+" or "w+";
		pidfile_handle, err = io.open(pidfile, mode);
		if not pidfile_handle then
			module:log("error", "Couldn't write pidfile at %s; %s", pidfile, err);
			prosody.shutdown("Couldn't write pidfile");
		else
			if not lfs.lock(pidfile_handle, "w") then -- Exclusive lock
				local other_pid = pidfile_handle:read("*a");
				module:log("error", "Another Prosody instance seems to be running with PID %s, quitting", other_pid);
				pidfile_handle = nil;
				prosody.shutdown("Prosody already running");
			else
				pidfile_handle:close();
				pidfile_handle, err = io.open(pidfile, "w+");
				if not pidfile_handle then
					module:log("error", "Couldn't write pidfile at %s; %s", pidfile, err);
					prosody.shutdown("Couldn't write pidfile");
				else
					if lfs.lock(pidfile_handle, "w") then
						pidfile_handle:write(tostring(pposix.getpid()));
						pidfile_handle:flush();
					end
				end
			end
		end
	end
end

local daemonize = prosody.opts.daemonize;

if daemonize == nil then
	-- Fall back to config file if not specified on command-line
	daemonize = module:get_option_boolean("daemonize", nil);
	if daemonize ~= nil then
		module:log("warn", "The 'daemonize' option has been deprecated, specify -D or -F on the command line instead.");
		-- TODO: Write some docs and include a link in the warning.
	end
end

local function remove_log_sinks()
	local lm = require "core.loggingmanager";
	lm.register_sink_type("console", nil);
	lm.register_sink_type("stdout", nil);
	lm.reload_logging();
end

if daemonize then
	local function daemonize_server()
		module:log("info", "Prosody is about to detach from the console, disabling further console output");
		remove_log_sinks();
		local ok, ret = pposix.daemonize();
		if not ok then
			module:log("error", "Failed to daemonize: %s", ret);
		elseif ret and ret > 0 then
			os.exit(0);
		else
			module:log("info", "Successfully daemonized to PID %d", pposix.getpid());
			write_pidfile();
		end
	end
	module:hook("server-started", daemonize_server)
else
	-- Not going to daemonize, so write the pid of this process
	write_pidfile();
end

module:hook("server-stopped", remove_pidfile);

-- Set signal handlers
if have_signal then
	module:add_timer(0, function ()
		signal.signal("SIGTERM", function ()
			module:log("warn", "Received SIGTERM");
			prosody.unlock_globals();
			prosody.shutdown("Received SIGTERM");
			prosody.lock_globals();
		end);

		signal.signal("SIGHUP", function ()
			module:log("info", "Received SIGHUP");
			prosody.reload_config();
			-- this also reloads logging
		end);

		signal.signal("SIGINT", function ()
			module:log("info", "Received SIGINT");
			prosody.unlock_globals();
			prosody.shutdown("Received SIGINT");
			prosody.lock_globals();
		end);

		signal.signal("SIGUSR1", function ()
			module:log("info", "Received SIGUSR1");
			module:fire_event("signal/SIGUSR1");
		end);

		signal.signal("SIGUSR2", function ()
			module:log("info", "Received SIGUSR2");
			module:fire_event("signal/SIGUSR2");
		end);
	end);
end

-- For other modules to reference
features = {
	signal_events = true;
};