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-rw-r--r--util/statistics.lua315
1 files changed, 173 insertions, 142 deletions
diff --git a/util/statistics.lua b/util/statistics.lua
index 39954652..a8401168 100644
--- a/util/statistics.lua
+++ b/util/statistics.lua
@@ -1,160 +1,191 @@
-local t_sort = table.sort
-local m_floor = math.floor;
local time = require "util.time".now;
+local new_metric_registry = require "util.openmetrics".new_metric_registry;
+local render_histogram_le = require "util.openmetrics".render_histogram_le;
-local function nop_function() end
+-- BEGIN of Metric implementations
-local function percentile(arr, length, pc)
- local n = pc/100 * (length + 1);
- local k, d = m_floor(n), n%1;
- if k == 0 then
- return arr[1] or 0;
- elseif k >= length then
- return arr[length];
- end
- return arr[k] + d*(arr[k+1] - arr[k]);
+-- Gauges
+local gauge_metric_mt = {}
+gauge_metric_mt.__index = gauge_metric_mt
+
+local function new_gauge_metric()
+ local metric = { value = 0 }
+ setmetatable(metric, gauge_metric_mt)
+ return metric
+end
+
+function gauge_metric_mt:set(value)
+ self.value = value
+end
+
+function gauge_metric_mt:add(delta)
+ self.value = self.value + delta
end
-local function new_registry(config)
- config = config or {};
- local duration_sample_interval = config.duration_sample_interval or 5;
- local duration_max_samples = config.duration_max_stored_samples or 5000;
+function gauge_metric_mt:reset()
+ self.value = 0
+end
- local function get_distribution_stats(events, n_actual_events, since, new_time, units)
- local n_stored_events = #events;
- t_sort(events);
- local sum = 0;
- for i = 1, n_stored_events do
- sum = sum + events[i];
+function gauge_metric_mt:iter_samples()
+ local done = false
+ return function(_s)
+ if done then
+ return nil, true
end
+ done = true
+ return "", nil, _s.value
+ end, self
+end
- return {
- samples = events;
- sample_count = n_stored_events;
- count = n_actual_events,
- rate = n_actual_events/(new_time-since);
- average = n_stored_events > 0 and sum/n_stored_events or 0,
- min = events[1] or 0,
- max = events[n_stored_events] or 0,
- units = units,
- };
- end
+-- Counters
+local counter_metric_mt = {}
+counter_metric_mt.__index = counter_metric_mt
+
+local function new_counter_metric()
+ local metric = {
+ _created = time(),
+ value = 0,
+ }
+ setmetatable(metric, counter_metric_mt)
+ return metric
+end
+function counter_metric_mt:set(value)
+ self.value = value
+end
- local registry = {};
- local methods;
- methods = {
- amount = function (name, initial)
- local v = initial or 0;
- registry[name..":amount"] = function () return "amount", v; end
- return function (new_v) v = new_v; end
- end;
- counter = function (name, initial)
- local v = initial or 0;
- registry[name..":amount"] = function () return "amount", v; end
- return function (delta)
- v = v + delta;
- end;
- end;
- rate = function (name)
- local since, n = time(), 0;
- registry[name..":rate"] = function ()
- local t = time();
- local stats = {
- rate = n/(t-since);
- count = n;
- };
- since, n = t, 0;
- return "rate", stats.rate, stats;
- end;
- return function ()
- n = n + 1;
- end;
- end;
- distribution = function (name, unit, type)
- type = type or "distribution";
- local events, last_event = {}, 0;
- local n_actual_events = 0;
- local since = time();
-
- registry[name..":"..type] = function ()
- local new_time = time();
- local stats = get_distribution_stats(events, n_actual_events, since, new_time, unit);
- events, last_event = {}, 0;
- n_actual_events = 0;
- since = new_time;
- return type, stats.average, stats;
- end;
-
- return function (value)
- n_actual_events = n_actual_events + 1;
- if n_actual_events%duration_sample_interval == 1 then
- last_event = (last_event%duration_max_samples) + 1;
- events[last_event] = value;
- end
- end;
- end;
- sizes = function (name)
- return methods.distribution(name, "bytes", "size");
- end;
- times = function (name)
- local events, last_event = {}, 0;
- local n_actual_events = 0;
- local since = time();
-
- registry[name..":duration"] = function ()
- local new_time = time();
- local stats = get_distribution_stats(events, n_actual_events, since, new_time, "seconds");
- events, last_event = {}, 0;
- n_actual_events = 0;
- since = new_time;
- return "duration", stats.average, stats;
- end;
-
- return function ()
- n_actual_events = n_actual_events + 1;
- if n_actual_events%duration_sample_interval ~= 1 then
- return nop_function;
- end
-
- local start_time = time();
- return function ()
- local end_time = time();
- local duration = end_time - start_time;
- last_event = (last_event%duration_max_samples) + 1;
- events[last_event] = duration;
- end
- end;
- end;
-
- get_stats = function ()
- return registry;
- end;
- };
- return methods;
+function counter_metric_mt:add(value)
+ self.value = (self.value or 0) + value
end
-return {
- new = new_registry;
- get_histogram = function (duration, n_buckets)
- n_buckets = n_buckets or 100;
- local events, n_events = duration.samples, duration.sample_count;
- if not (events and n_events) then
- return nil, "not a valid distribution stat";
+function counter_metric_mt:iter_samples()
+ local step = 0
+ return function(_s)
+ step = step + 1
+ if step == 1 then
+ return "_created", nil, _s._created
+ elseif step == 2 then
+ return "_total", nil, _s.value
+ else
+ return nil, nil, true
+ end
+ end, self
+end
+
+function counter_metric_mt:reset()
+ self.value = 0
+end
+
+-- Histograms
+local histogram_metric_mt = {}
+histogram_metric_mt.__index = histogram_metric_mt
+
+local function new_histogram_metric(buckets)
+ local metric = {
+ _created = time(),
+ _sum = 0,
+ _count = 0,
+ }
+ -- the order of buckets matters unfortunately, so we cannot directly use
+ -- the thresholds as table keys
+ for i, threshold in ipairs(buckets) do
+ metric[i] = {
+ threshold = threshold,
+ threshold_s = render_histogram_le(threshold),
+ count = 0
+ }
+ end
+ setmetatable(metric, histogram_metric_mt)
+ return metric
+end
+
+function histogram_metric_mt:sample(value)
+ -- According to the I-D, values must be part of all buckets
+ for i, bucket in pairs(self) do
+ if "number" == type(i) and bucket.threshold > value then
+ bucket.count = bucket.count + 1
end
- local histogram = {};
+ end
+ self._sum = self._sum + value
+ self._count = self._count + 1
+end
- for i = 1, 100, 100/n_buckets do
- histogram[i] = percentile(events, n_events, i);
+function histogram_metric_mt:iter_samples()
+ local key = nil
+ return function (_s)
+ local data
+ key, data = next(_s, key)
+ if key == "_created" or key == "_sum" or key == "_count" then
+ return key, nil, data
+ elseif key ~= nil then
+ return "_bucket", {["le"] = data.threshold_s}, data.count
+ else
+ return nil, nil, nil
end
- return histogram;
- end;
+ end, self
+end
- get_percentile = function (duration, pc)
- local events, n_events = duration.samples, duration.sample_count;
- if not (events and n_events) then
- return nil, "not a valid distribution stat";
+function histogram_metric_mt:reset()
+ self._created = time()
+ self._count = 0
+ self._sum = 0
+ for i, bucket in pairs(self) do
+ if "number" == type(i) then
+ bucket.count = 0
end
- return percentile(events, n_events, pc);
- end;
+ end
+end
+
+-- Summary
+local summary_metric_mt = {}
+summary_metric_mt.__index = summary_metric_mt
+
+local function new_summary_metric()
+ -- quantiles are not supported yet
+ local metric = {
+ _created = time(),
+ _sum = 0,
+ _count = 0,
+ }
+ setmetatable(metric, summary_metric_mt)
+ return metric
+end
+
+function summary_metric_mt:sample(value)
+ self._sum = self._sum + value
+ self._count = self._count + 1
+end
+
+function summary_metric_mt:iter_samples()
+ local key = nil
+ return function (_s)
+ local data
+ key, data = next(_s, key)
+ return key, nil, data
+ end, self
+end
+
+function summary_metric_mt:reset()
+ self._created = time()
+ self._count = 0
+ self._sum = 0
+end
+
+local pull_backend = {
+ gauge = new_gauge_metric,
+ counter = new_counter_metric,
+ histogram = new_histogram_metric,
+ summary = new_summary_metric,
+}
+
+-- END of Metric implementations
+
+local function new()
+ return {
+ metric_registry = new_metric_registry(pull_backend),
+ }
+end
+
+return {
+ new = new;
}