prosody
5f15ab7c6ae5
spec/util_events_spec.lua

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spec/util_events_spec.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 11060:19dd9522f107
line wrap: on
line source

local events = require "util.events";

describe("util.events", function ()
	it("should export a new() function", function ()
		assert.is_function(events.new);
	end);
	describe("new()", function ()
		it("should return return a new events object", function ()
			local e = events.new();
			assert.is_function(e.add_handler);
			assert.is_function(e.remove_handler);
		end);
	end);

	local e, h;


	describe("API", function ()
		before_each(function ()
			e = events.new();
			h = spy.new(function () end);
		end);

		it("should call handlers when an event is fired", function ()
			e.add_handler("myevent", h);
			e.fire_event("myevent");
			assert.spy(h).was_called();
		end);

		it("should not call handlers when a different event is fired", function ()
			e.add_handler("myevent", h);
			e.fire_event("notmyevent");
			assert.spy(h).was_not_called();
		end);

		it("should pass the data argument to handlers", function ()
			e.add_handler("myevent", h);
			e.fire_event("myevent", "mydata");
			assert.spy(h).was_called_with("mydata");
		end);

		it("should support non-string events", function ()
			local myevent = {};
			e.add_handler(myevent, h);
			e.fire_event(myevent, "mydata");
			assert.spy(h).was_called_with("mydata");
		end);

		it("should call handlers in priority order", function ()
			local data = {};
			e.add_handler("myevent", function () table.insert(data, "h1"); end, 5);
			e.add_handler("myevent", function () table.insert(data, "h2"); end, 3);
			e.add_handler("myevent", function () table.insert(data, "h3"); end);
			e.fire_event("myevent", "mydata");
			assert.same(data, { "h1", "h2", "h3" });
		end);

		it("should support non-integer priority values", function ()
			local data = {};
			e.add_handler("myevent", function () table.insert(data, "h1"); end, 1);
			e.add_handler("myevent", function () table.insert(data, "h2"); end, 0.5);
			e.add_handler("myevent", function () table.insert(data, "h3"); end, 0.25);
			e.fire_event("myevent", "mydata");
			assert.same(data, { "h1", "h2", "h3" });
		end);

		it("should support negative priority values", function ()
			local data = {};
			e.add_handler("myevent", function () table.insert(data, "h1"); end, 1);
			e.add_handler("myevent", function () table.insert(data, "h2"); end, 0);
			e.add_handler("myevent", function () table.insert(data, "h3"); end, -1);
			e.fire_event("myevent", "mydata");
			assert.same(data, { "h1", "h2", "h3" });
		end);

		it("should support removing handlers", function ()
			e.add_handler("myevent", h);
			e.fire_event("myevent");
			e.remove_handler("myevent", h);
			e.fire_event("myevent");
			assert.spy(h).was_called(1);
		end);

		it("should support adding multiple handlers at the same time", function ()
			local ht = {
				myevent1 = spy.new(function () end);
				myevent2 = spy.new(function () end);
				myevent3 = spy.new(function () end);
			};
			e.add_handlers(ht);
			e.fire_event("myevent1");
			e.fire_event("myevent2");
			assert.spy(ht.myevent1).was_called();
			assert.spy(ht.myevent2).was_called();
			assert.spy(ht.myevent3).was_not_called();
		end);

		it("should support removing multiple handlers at the same time", function ()
			local ht = {
				myevent1 = spy.new(function () end);
				myevent2 = spy.new(function () end);
				myevent3 = spy.new(function () end);
			};
			e.add_handlers(ht);
			e.remove_handlers(ht);
			e.fire_event("myevent1");
			e.fire_event("myevent2");
			assert.spy(ht.myevent1).was_not_called();
			assert.spy(ht.myevent2).was_not_called();
			assert.spy(ht.myevent3).was_not_called();
		end);

		pending("should support adding handlers within an event handler")
		pending("should support removing handlers within an event handler")

		it("should support getting the current handlers for an event", function ()
			e.add_handler("myevent", h);
			local handlers = e.get_handlers("myevent");
			assert.equal(h, handlers[1]);
		end);

		describe("wrappers", function ()
			local w
			before_each(function ()
				w = spy.new(function (handlers, event_name, event_data)
					assert.is_function(handlers);
					assert.equal("myevent", event_name)
					assert.equal("abc", event_data);
					return handlers(event_name, event_data);
				end);
			end);

			it("should get called", function ()
				e.add_wrapper("myevent", w);
				e.add_handler("myevent", h);
				e.fire_event("myevent", "abc");
				assert.spy(w).was_called(1);
				assert.spy(h).was_called(1);
			end);

			it("should be removable", function ()
				e.add_wrapper("myevent", w);
				e.add_handler("myevent", h);
				e.fire_event("myevent", "abc");
				e.remove_wrapper("myevent", w);
				e.fire_event("myevent", "abc");
				assert.spy(w).was_called(1);
				assert.spy(h).was_called(2);
			end);

			it("should allow multiple wrappers", function ()
				local w2 = spy.new(function (handlers, event_name, event_data)
					return handlers(event_name, event_data);
				end);
				e.add_wrapper("myevent", w);
				e.add_handler("myevent", h);
				e.add_wrapper("myevent", w2);
				e.fire_event("myevent", "abc");
				e.remove_wrapper("myevent", w);
				e.fire_event("myevent", "abc");
				assert.spy(w).was_called(1);
				assert.spy(w2).was_called(2);
				assert.spy(h).was_called(2);
			end);

			it("should support a mix of global and event wrappers", function ()
				local w2 = spy.new(function (handlers, event_name, event_data)
					return handlers(event_name, event_data);
				end);
				e.add_wrapper(false, w);
				e.add_handler("myevent", h);
				e.add_wrapper("myevent", w2);
				e.fire_event("myevent", "abc");
				e.remove_wrapper(false, w);
				e.fire_event("myevent", "abc");
				assert.spy(w).was_called(1);
				assert.spy(w2).was_called(2);
				assert.spy(h).was_called(2);
			end);
		end);

		describe("global wrappers", function ()
			local w
			before_each(function ()
				w = spy.new(function (handlers, event_name, event_data)
					assert.is_function(handlers);
					assert.equal("myevent", event_name)
					assert.equal("abc", event_data);
					return handlers(event_name, event_data);
				end);
			end);

			it("should get called", function ()
				e.add_wrapper(false, w);
				e.add_handler("myevent", h);
				e.fire_event("myevent", "abc");
				assert.spy(w).was_called(1);
				assert.spy(h).was_called(1);
			end);

			it("should be removable", function ()
				e.add_wrapper(false, w);
				e.add_handler("myevent", h);
				e.fire_event("myevent", "abc");
				e.remove_wrapper(false, w);
				e.fire_event("myevent", "abc");
				assert.spy(w).was_called(1);
				assert.spy(h).was_called(2);
			end);
		end);

		describe("debug hooks", function ()
			it("should get called", function ()
				local d = spy.new(function (handler, event_name, event_data) --luacheck: ignore 212/event_name
					return handler(event_data);
				end);

				e.add_handler("myevent", h);
				e.fire_event("myevent");

				assert.spy(h).was_called(1);
				assert.spy(d).was_called(0);

				assert.is_nil(e.set_debug_hook(d));

				e.fire_event("myevent", { mydata = true });

				assert.spy(h).was_called(2);
				assert.spy(d).was_called(1);
				assert.spy(d).was_called_with(h, "myevent", { mydata = true });

				assert.equal(d, e.set_debug_hook(nil));

				e.fire_event("myevent", { mydata = false });

				assert.spy(h).was_called(3);
				assert.spy(d).was_called(1);
			end);
			it("setting should return any existing debug hook", function ()
				local function f() end
				local function g() end
				assert.is_nil(e.set_debug_hook(f));
				assert.is_equal(f, e.set_debug_hook(g));
				assert.is_equal(g, e.set_debug_hook(f));
				assert.is_equal(f, e.set_debug_hook(nil));
				assert.is_nil(e.set_debug_hook(f));
			end);
		end);
	end);
end);