aggregated registry refactor

index.js

@@ -22,4 +22,4 @@ exports.exponentialBuckets = require('./lib/bucketGenerators').exponentialBucket
 exports.collectDefaultMetrics = require('./lib/defaultMetrics');
 
 exports.aggregators = require('./lib/metricAggregators').aggregators;
-exports.AggregatorRegistry = require('./lib/cluster');
+exports.AggregatorRegistry = require('./lib/aggregatorRegistry');

lib/aggregatorRegistry.js

@@ -0,0 +1,95 @@
+'use strict';
+
+const Registry = require('./registry');
+const { Grouper } = require('./util');
+const { aggregators } = require('./metricAggregators');
+const WorkerThreads = require('./workerThreads');
+const Cluster = require('./cluster');
+
+class AggregatorRegistry extends Registry {
+ constructor() {
+ super();
+
+ this.registries = [Registry.globalRegistry];
+ this.workerThreads = new WorkerThreads({ registries: this.registries });
+ this.cluster = new Cluster({ registries: this.registries });
+ }
+
+ setWorkers(workers) {
+ this.workerThreads.set(workers);
+ }
+
+ clusterMetrics() {
+ return this.cluster.getMetrics();
+ }
+
+ workerThreadsMetrics() {
+ return this.workerThreads.getMetrics();
+ }
+
+ /**
+ * Sets the registry or registries to be aggregated. Call from workers to
+ * use a registry/registries other than the default global registry.
+ * @param {Array<Registry>|Registry} registries Registry or registries to be
+ * aggregated.
+ * @return {void}
+ */
+ setRegistries(registries) {
+ if (!Array.isArray(registries)) registries = [registries];
+
+ registries.forEach(registry => {
+ if (!(registry instanceof Registry)) {
+ throw new TypeError(`Expected Registry, got ${typeof registry}`);
+ }
+ });
+
+ this.registries = registries;
+ }
+
+ /**
+ * Creates a new Registry instance from an array of metrics that were
+ * created by `registry.getMetricsAsJSON()`. Metrics are aggregated using
+ * the method specified by their `aggregator` property, or by summation if
+ * `aggregator` is undefined.
+ * @param {Array} metrics Array of metrics, each of which created by
+ * `registry.getMetricsAsJSON()`.
+ * @return {Registry} aggregated registry.
+ */
+ static aggregate(metrics) {
+ const aggregatedRegistry = new Registry();
+ const metricsByName = new Grouper();
+
+ // Gather by name
+ metrics.forEach(m =>
+ m.forEach(metric => {
+ metricsByName.add(metric.name, metric);
+ }),
+ );
+
+ // Aggregate gathered metrics.
+ metricsByName.forEach(metric => {
+ const aggregatorName = metric[0].aggregator;
+ const aggregatorFn = aggregators[aggregatorName];
+
+ if (typeof aggregatorFn !== 'function') {
+ throw new Error(`'${aggregatorName}' is not a defined aggregator.`);
+ }
+
+ const aggregatedMetric = aggregatorFn(metric);
+ // NB: The 'omit' aggregator returns undefined.
+ if (aggregatedMetric) {
+ const aggregatedMetricWrapper = Object.assign(
+ {
+ get: () => aggregatedMetric,
+ },
+ aggregatedMetric,
+ );
+ aggregatedRegistry.registerMetric(aggregatedMetricWrapper);
+ }
+ });
+
+ return aggregatedRegistry;
+ }
+}
+
+module.exports = AggregatorRegistry;