prosody
5f15ab7c6ae5
spec/util_cache_spec.lua

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spec/util_cache_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 11366:618ab9bba1c2
child 12571:c4337ff4f1c4
line wrap: on
line source


local cache = require "util.cache";

describe("util.cache", function()
	describe("#new()", function()
		it("should work", function()

			local c = cache.new(5);

			local function expect_kv(key, value, actual_key, actual_value)
				assert.are.equal(key, actual_key, "key incorrect");
				assert.are.equal(value, actual_value, "value incorrect");
			end

			expect_kv(nil, nil, c:head());
			expect_kv(nil, nil, c:tail());

			assert.are.equal(c:count(), 0);

			c:set("one", 1)
			assert.are.equal(c:count(), 1);
			expect_kv("one", 1, c:head());
			expect_kv("one", 1, c:tail());

			c:set("two", 2)
			expect_kv("two", 2, c:head());
			expect_kv("one", 1, c:tail());

			c:set("three", 3)
			expect_kv("three", 3, c:head());
			expect_kv("one", 1, c:tail());

			c:set("four", 4)
			c:set("five", 5);
			assert.are.equal(c:count(), 5);
			expect_kv("five", 5, c:head());
			expect_kv("one", 1, c:tail());

			c:set("foo", nil);
			assert.are.equal(c:count(), 5);
			expect_kv("five", 5, c:head());
			expect_kv("one", 1, c:tail());

			assert.are.equal(c:get("one"), 1);
			expect_kv("five", 5, c:head());
			expect_kv("one", 1, c:tail());

			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), 3);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);

			assert.are.equal(c:get("foo"), nil);
			assert.are.equal(c:get("bar"), nil);

			c:set("six", 6);
			assert.are.equal(c:count(), 5);
			expect_kv("six", 6, c:head());
			expect_kv("two", 2, c:tail());

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), 3);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);

			c:set("three", nil);
			assert.are.equal(c:count(), 4);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);

			c:set("seven", 7);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);

			c:set("eight", 8);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), nil);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);
			assert.are.equal(c:get("eight"), 8);

			c:set("four", 4);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), nil);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);
			assert.are.equal(c:get("eight"), 8);

			c:set("nine", 9);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), nil);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), nil);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);
			assert.are.equal(c:get("eight"), 8);
			assert.are.equal(c:get("nine"), 9);

			do
				local keys = { "nine", "four", "eight", "seven", "six" };
				local values = { 9, 4, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 5);

				c:set("four", "2+2");
				assert.are.equal(c:count(), 5);

				assert.are.equal(c:get("one"), nil);
				assert.are.equal(c:get("two"), nil);
				assert.are.equal(c:get("three"), nil);
				assert.are.equal(c:get("four"), "2+2");
				assert.are.equal(c:get("five"), nil);
				assert.are.equal(c:get("six"), 6);
				assert.are.equal(c:get("seven"), 7);
				assert.are.equal(c:get("eight"), 8);
				assert.are.equal(c:get("nine"), 9);
			end

			do
				local keys = { "four", "nine", "eight", "seven", "six" };
				local values = { "2+2", 9, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 5);

				c:set("foo", nil);
				assert.are.equal(c:count(), 5);

				assert.are.equal(c:get("one"), nil);
				assert.are.equal(c:get("two"), nil);
				assert.are.equal(c:get("three"), nil);
				assert.are.equal(c:get("four"), "2+2");
				assert.are.equal(c:get("five"), nil);
				assert.are.equal(c:get("six"), 6);
				assert.are.equal(c:get("seven"), 7);
				assert.are.equal(c:get("eight"), 8);
				assert.are.equal(c:get("nine"), 9);
			end

			do
				local keys = { "four", "nine", "eight", "seven", "six" };
				local values = { "2+2", 9, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 5);

				c:set("four", nil);

				assert.are.equal(c:get("one"), nil);
				assert.are.equal(c:get("two"), nil);
				assert.are.equal(c:get("three"), nil);
				assert.are.equal(c:get("four"), nil);
				assert.are.equal(c:get("five"), nil);
				assert.are.equal(c:get("six"), 6);
				assert.are.equal(c:get("seven"), 7);
				assert.are.equal(c:get("eight"), 8);
				assert.are.equal(c:get("nine"), 9);
			end

			do
				local keys = { "nine", "eight", "seven", "six" };
				local values = { 9, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 4);
			end

			do
				local evicted_key, evicted_value;
				local c2 = cache.new(3, function (_key, _value)
					evicted_key, evicted_value = _key, _value;
				end);
				local function set(k, v, should_evict_key, should_evict_value)
					evicted_key, evicted_value = nil, nil;
					c2:set(k, v);
					assert.are.equal(evicted_key, should_evict_key);
					assert.are.equal(evicted_value, should_evict_value);
				end
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)

				set("b", 2)
				set("c", 3)
				set("b", 2)
				set("d", 4, "a", 1)
				set("e", 5, "c", 3)
			end

			do
				local evicted_key, evicted_value;
				local c3 = cache.new(1, function (_key, _value)
					evicted_key, evicted_value = _key, _value;
					if _key == "a" then
						-- Sanity check for what we're evicting
						assert.are.equal(_key, "a");
						assert.are.equal(_value, 1);
						-- We're going to block eviction of this key/value, so set to nil...
						evicted_key, evicted_value = nil, nil;
						-- Returning false to block eviction
						return false
					end
				end);
				local function set(k, v, should_evict_key, should_evict_value)
					evicted_key, evicted_value = nil, nil;
					local ret = c3:set(k, v);
					assert.are.equal(evicted_key, should_evict_key);
					assert.are.equal(evicted_value, should_evict_value);
					return ret;
				end
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)

				-- Our on_evict prevents "a" from being evicted, causing this to fail...
				assert.are.equal(set("b", 2), false, "Failed to prevent eviction, or signal result");

				expect_kv("a", 1, c3:head());
				expect_kv("a", 1, c3:tail());

				-- Check the final state is what we expect
				assert.are.equal(c3:get("a"), 1);
				assert.are.equal(c3:get("b"), nil);
				assert.are.equal(c3:count(), 1);
			end


			local c4 = cache.new(3, false);

			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("b", 2), true);
			assert.are.equal(c4:set("c", 3), true);
			assert.are.equal(c4:set("d", 4), false);
			assert.are.equal(c4:set("d", 4), false);
			assert.are.equal(c4:set("d", 4), false);

			expect_kv("c", 3, c4:head());
			expect_kv("a", 1, c4:tail());

			local c5 = cache.new(3, function (k, v) --luacheck: ignore 212/v
				if k == "a" then
					return nil;
				elseif k == "b" then
					return true;
				end
				return false;
			end);

			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("b", 2), true);
			assert.are.equal(c5:set("c", 3), true);
			assert.are.equal(c5:set("d", 4), true); -- "a" evicted (cb returned nil)
			assert.are.equal(c5:set("d", 4), true); -- nop
			assert.are.equal(c5:set("d", 4), true); -- nop
			assert.are.equal(c5:set("e", 5), true); -- "b" evicted (cb returned true)
			assert.are.equal(c5:set("f", 6), false); -- "c" won't evict (cb returned false)

			expect_kv("e", 5, c5:head());
			expect_kv("c", 3, c5:tail());

		end);

		(_VERSION=="Lua 5.1" and pending or it)(":table works", function ()
			local t = cache.new(3):table();
			assert.is.table(t);
			t["a"] = "1";
			assert.are.equal(t["a"], "1");
			t["b"] = "2";
			assert.are.equal(t["b"], "2");
			t["c"] = "3";
			assert.are.equal(t["c"], "3");
			t["d"] = "4";
			assert.are.equal(t["d"], "4");
			assert.are.equal(t["a"], nil);

				local i = spy.new(function () end);
				for k, v in pairs(t) do
					i(k,v)
				end
				assert.spy(i).was_called();
				assert.spy(i).was_called_with("b", "2");
				assert.spy(i).was_called_with("c", "3");
				assert.spy(i).was_called_with("d", "4");
		end);
	end);
end);