Software / code / prosody
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 |
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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