Support for getting clustered metrics as object

index.d.ts

@@ -92,6 +92,20 @@ export class AggregatorRegistry extends Registry {
 	 */
 	clusterMetrics(): Promise<string>;
 
+	/**
+	 * Gets aggregated metrics for all workers as objects
+	 * @return {Promise<metric[]>} Promise that resolves with the aggregated
+	 * metrics.
+	 */
+	getClusterMetricsAsJSON(): Promise<metric[]>;
+
+	/**
+	 * Gets aggregated metrics for all workers as objects
+	 * @return {Promise<metric[]>} Promise that resolves with the aggregated
+	 * metrics.
+	 */
+	getClusterMetricsAsArray(): Promise<metric[]>;
+
 	/**
 	 * Creates a new Registry instance from an array of metrics that were
 	 * created by `registry.getMetricsAsJSON()`. Metrics are aggregated using
@@ -560,23 +574,23 @@ export class Pushgateway {
 	 */
 	pushAdd(
 		params: Pushgateway.Parameters,
-	): Promise<{ resp?: unknown, body?: unknown }>;
+	): Promise<{ resp?: unknown; body?: unknown }>;
 
 	/**
 	 * Overwrite all metric (using PUT to Pushgateway)
 	 * @param params Push parameters
 	 */
 	push(
 		params: Pushgateway.Parameters,
-	): Promise<{ resp?: unknown, body?: unknown }>;
+	): Promise<{ resp?: unknown; body?: unknown }>;
 
 	/**
 	 * Delete all metrics for jobName
 	 * @param params Push parameters
 	 */
 	delete(
 		params: Pushgateway.Parameters,
-	): Promise<{ resp?: unknown, body?: unknown }>;
+	): Promise<{ resp?: unknown; body?: unknown }>;
 }
 
 export namespace Pushgateway {

lib/cluster.js

@@ -40,48 +40,29 @@ class AggregatorRegistry extends Registry {
 	 *   metrics.
 	 */
 	clusterMetrics() {
-		const requestId = requestCtr++;
-
-		return new Promise((resolve, reject) => {
-			let settled = false;
-			function done(err, result) {
-				if (settled) return;
-				settled = true;
-				if (err) reject(err);
-				else resolve(result);
-			}
+		return clusterMetricsRequest('string');
+	}
 
-			const request = {
-				responses: [],
-				pending: 0,
-				done,
-				errorTimeout: setTimeout(() => {
-					const err = new Error('Operation timed out.');
-					request.done(err);
-				}, 5000),
-			};
-			requests.set(requestId, request);
-
-			const message = {
-				type: GET_METRICS_REQ,
-				requestId,
-			};
-
-			for (const id in cluster().workers) {
-				// If the worker exits abruptly, it may still be in the workers
-				// list but not able to communicate.
-				if (cluster().workers[id].isConnected()) {
-					cluster().workers[id].send(message);
-					request.pending++;
-				}
-			}
+	/**
+	 * Gets aggregated metrics for all workers in JSON format.
+	 * The optional callback and returned Promise resolve with the same value;
+	 * either may be used.
+	 * @return {Promise<Object>} Promise that resolves with the aggregated
+	 *   metrics in JSON format.
+	 */
+	getClusterMetricsAsJSON() {
+		return clusterMetricsRequest('json');
+	}
 
-			if (request.pending === 0) {
-				// No workers were up
-				clearTimeout(request.errorTimeout);
-				process.nextTick(() => done(null, ''));
-			}
-		});
+	/**
+	 * Gets aggregated metrics for all workers as an array.
+	 * The optional callback and returned Promise resolve with the same value;
+	 * either may be used.
+	 * @return {Promise<Object>} Promise that resolves with the aggregated
+	 *   metrics in JSON format.
+	 */
+	getClusterMetricsAsArray() {
+		return clusterMetricsRequest('array');
 	}
 
 	/**
@@ -174,8 +155,21 @@ function addListeners() {
 					clearTimeout(request.errorTimeout);
 
 					const registry = AggregatorRegistry.aggregate(request.responses);
-					const promString = registry.metrics();
-					request.done(null, promString);
+					switch (request.format) {
+						case 'json':
+							request.done(null, registry.getMetricsAsJSON());
+							break;
+						case 'array':
+							request.done(null, registry.getMetricsAsArray());
+							break;
+						case 'string':
+							request.done(null, registry.metrics());
+							break;
+						default:
+							request.done(
+								new Error(`unknown metrics format: ${request.format}`),
+							);
+					}
 				}
 			}
 		});
@@ -205,4 +199,64 @@ function addListeners() {
 	}
 }
 
+function clusterMetricsRequest(format) {
+	const requestId = requestCtr++;
+
+	return new Promise((resolve, reject) => {
+		let settled = false;
+		function done(err, result) {
+			if (settled) return;
+			settled = true;
+			if (err) reject(err);
+			else resolve(result);
+		}
+
+		const request = {
+			responses: [],
+			pending: 0,
+			format,
+			done,
+			errorTimeout: setTimeout(() => {
+				const err = new Error('Operation timed out.');
+				request.done(err);
+			}, 5000),
+		};
+		requests.set(requestId, request);
+
+		const message = {
+			type: GET_METRICS_REQ,
+			requestId,
+		};
+
+		for (const id in cluster().workers) {
+			// If the worker exits abruptly, it may still be in the workers
+			// list but not able to communicate.
+			if (cluster().workers[id].isConnected()) {
+				cluster().workers[id].send(message);
+				request.pending++;
+			}
+		}
+
+		if (request.pending === 0) {
+			// No workers were up
+			clearTimeout(request.errorTimeout);
+			switch (request.format) {
+				case 'json':
+					process.nextTick(() => done(null, []));
+					break;
+				case 'array':
+					process.nextTick(() => done(null, []));
+					break;
+				case 'string':
+					process.nextTick(() => done(null, ''));
+					break;
+				default:
+					process.nextTick(() =>
+						done(new Error(`unknown metrics format: ${request.format}`)),
+					);
+			}
+		}
+	});
+}
+
 module.exports = AggregatorRegistry;

test/clusterTest.js

@@ -41,6 +41,24 @@ describe('AggregatorRegistry', () => {
 		});
 	});
 
+	describe('aggregatorRegistry.getClusterMetricsAsJSON()', () => {
+		it('works properly if there are no cluster workers', async () => {
+			const AggregatorRegistry = require('../lib/cluster');
+			const ar = new AggregatorRegistry();
+			const metrics = await ar.getClusterMetricsAsJSON();
+			expect(metrics).toEqual([]);
+		});
+	});
+
+	describe('aggregatorRegistry.getClusterMetricsAsArray()', () => {
+		it('works properly if there are no cluster workers', async () => {
+			const AggregatorRegistry = require('../lib/cluster');
+			const ar = new AggregatorRegistry();
+			const metrics = await ar.getClusterMetricsAsArray();
+			expect(metrics).toEqual([]);
+		});
+	});
+
 	describe('AggregatorRegistry.aggregate()', () => {
 		const Registry = require('../lib/cluster');
 		// These mimic the output of `getMetricsAsJSON`.