File

plugins/mod_pubsub/mod_pubsub.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 11202:58492b4b85ea
child 11631:6641ca266d94
line wrap: on
line source

local pubsub = require "util.pubsub";
local st = require "util.stanza";
local jid_bare = require "util.jid".bare;
local usermanager = require "core.usermanager";
local new_id = require "util.id".medium;
local storagemanager = require "core.storagemanager";

local xmlns_pubsub = "http://jabber.org/protocol/pubsub";
local xmlns_pubsub_event = "http://jabber.org/protocol/pubsub#event";
local xmlns_pubsub_owner = "http://jabber.org/protocol/pubsub#owner";

local autocreate_on_publish = module:get_option_boolean("autocreate_on_publish", false);
local autocreate_on_subscribe = module:get_option_boolean("autocreate_on_subscribe", false);
local pubsub_disco_name = module:get_option_string("name", "Prosody PubSub Service");
local expose_publisher = module:get_option_boolean("expose_publisher", false)

local service;

local lib_pubsub = module:require "pubsub";

module:depends("disco");
module:add_identity("pubsub", "service", pubsub_disco_name);
module:add_feature("http://jabber.org/protocol/pubsub");

function handle_pubsub_iq(event)
	return lib_pubsub.handle_pubsub_iq(event, service);
end

-- An itemstore supports the following methods:
--   items(): iterator over (id, item)
--   get(id): return item with id
--   set(id, item): set id to item
--   clear(): clear all items
--   resize(n): set new limit and trim oldest items
--   tail(): return the latest item

-- A nodestore supports the following methods:
--   set(node_name, node_data)
--   get(node_name)
--   users(): iterator over (node_name)


local node_store = module:open_store(module.name.."_nodes");

local function create_simple_itemstore(node_config, node_name) --> util.cache like object
	local driver = storagemanager.get_driver(module.host, "pubsub_data");
	local archive = driver:open("pubsub_"..node_name, "archive");
	return lib_pubsub.archive_itemstore(archive, node_config, nil, node_name);
end

function simple_broadcast(kind, node, jids, item, actor, node_obj)
	if node_obj then
		if node_obj.config["notify_"..kind] == false then
			return;
		end
	end
	if kind == "retract" then
		kind = "items"; -- XEP-0060 signals retraction in an <items> container
	end

	if item then
		item = st.clone(item);
		item.attr.xmlns = nil; -- Clear the pubsub namespace
		if kind == "items" then
			if node_obj and node_obj.config.include_payload == false then
				item:maptags(function () return nil; end);
			end
			if expose_publisher and actor then
				item.attr.publisher = actor
			end
		end
	end

	local id = new_id();
	local msg_type = node_obj and node_obj.config.notification_type or "headline";
	local message = st.message({ from = module.host, type = msg_type, id = id })
		:tag("event", { xmlns = xmlns_pubsub_event })
			:tag(kind, { node = node });

	if item then
		message:add_child(item);
	end

	local summary;
	if item and item.tags[1] then
		local payload = item.tags[1];
		summary = module:fire_event("pubsub-summary/"..payload.attr.xmlns, {
			kind = kind, node = node, jids = jids, actor = actor, item = item, payload = payload,
		});
	end

	for jid, options in pairs(jids) do
		local new_stanza = st.clone(message);
		if summary and type(options) == "table" and options["pubsub#include_body"] then
			new_stanza:body(summary);
		end
		new_stanza.attr.to = jid;
		module:send(new_stanza);
	end
end

local max_max_items = module:get_option_number("pubsub_max_items", 256);
function check_node_config(node, actor, new_config) -- luacheck: ignore 212/node 212/actor
	if (new_config["max_items"] or 1) > max_max_items then
		return false;
	end
	if new_config["access_model"] ~= "whitelist"
	and new_config["access_model"] ~= "open" then
		return false;
	end
	return true;
end

function is_item_stanza(item)
	return st.is_stanza(item) and item.attr.xmlns == xmlns_pubsub and item.name == "item" and #item.tags == 1;
end

-- Compose a textual representation of Atom payloads
module:hook("pubsub-summary/http://www.w3.org/2005/Atom", function (event)
	local payload = event.payload;
	local title = payload:get_child_text("title");
	local summary = payload:get_child_text("summary");
	if not summary and title then
		local author = payload:find("author/name#");
		summary = title;
		if author then
			summary = author .. " posted " .. summary;
		end
	end
	return summary;
end, -1);

module:hook("iq/host/"..xmlns_pubsub..":pubsub", handle_pubsub_iq);
module:hook("iq/host/"..xmlns_pubsub_owner..":pubsub", handle_pubsub_iq);

local function add_disco_features_from_service(service) --luacheck: ignore 431/service
	for feature in lib_pubsub.get_feature_set(service) do
		module:add_feature(xmlns_pubsub.."#"..feature);
	end
end

module:hook("host-disco-info-node", function (event)
	return lib_pubsub.handle_disco_info_node(event, service);
end);

module:hook("host-disco-items-node", function (event)
	return lib_pubsub.handle_disco_items_node(event, service);
end);


module:hook("host-disco-items", function (event)
	local stanza, reply = event.stanza, event.reply;
	local ok, ret = service:get_nodes(stanza.attr.from);
	if not ok then
		return;
	end
	for node, node_obj in pairs(ret) do
		reply:tag("item", { jid = module.host, node = node, name = node_obj.config.title }):up();
	end
end);

local admin_aff = module:get_option_string("default_admin_affiliation", "owner");
local function get_affiliation(jid)
	local bare_jid = jid_bare(jid);
	if bare_jid == module.host or usermanager.is_admin(bare_jid, module.host) then
		return admin_aff;
	end
end

function get_service()
	return service;
end

function set_service(new_service)
	service = new_service;
	module.environment.service = service;
	add_disco_features_from_service(service);
end

function module.save()
	return { service = service };
end

function module.restore(data)
	set_service(data.service);
end

function module.load()
	if module.reloading then return; end

	set_service(pubsub.new({
		autocreate_on_publish = autocreate_on_publish;
		autocreate_on_subscribe = autocreate_on_subscribe;

		nodestore = node_store;
		itemstore = create_simple_itemstore;
		broadcaster = simple_broadcast;
		itemcheck = is_item_stanza;
		check_node_config = check_node_config;
		get_affiliation = get_affiliation;

		normalize_jid = jid_bare;
	}));
end