feat: add option to exclude specific default metrics from collection

CHANGELOG.md

@@ -44,6 +44,7 @@ This release marks our first release under the Prometheus umbrella.
 
 ### Added
 
+- Add option to exclude selected default metrics from being collected
 - Add `nodejs_eventloop_utilization_summary` and `nodejs_eventloop_utilization_histogram` to the default metrics
 - Add debug logging for metrics collection failures.
 - Node 26 added to the test matrix

index.d.ts

@@ -865,6 +865,22 @@ export function exponentialBuckets(
 	count: number,
 ): number[];
 
+type AvailableDefaultMetrics =
+	| 'processCpuTotal'
+	| 'processStartTime'
+	| 'osMemoryHeap'
+	| 'processOpenFileDescriptors'
+	| 'processMaxFileDescriptors'
+	| 'eventLoopLag'
+	| 'eventLoopUtilization'
+	| 'processResources'
+	| 'processHandles'
+	| 'processRequests'
+	| 'heapSizeAndUsed'
+	| 'heapSpacesSizeAndUsed'
+	| 'version'
+	| 'gc';
+
 export interface DefaultMetricsCollectorConfiguration<
 	T extends RegistryContentType,
 > {
@@ -878,6 +894,7 @@ export interface DefaultMetricsCollectorConfiguration<
 	eventLoopUtilizationAgeBuckets?: number;
 	eventLoopUtilizationMaxAgeSeconds?: number;
 	labels?: object;
+	exclude?: AvailableDefaultMetrics[];
 }
 
 export const collectDefaultMetrics: {
@@ -889,7 +906,7 @@ export const collectDefaultMetrics: {
 		config?: DefaultMetricsCollectorConfiguration<T>,
 	): void;
 	/** All available default metrics */
-	metricsList: string[];
+	metricsList: AvailableDefaultMetrics[];
 };
 
 /**

lib/defaultMetrics.js

@@ -60,10 +60,13 @@ module.exports = function collectDefaultMetrics(config) {
 		throw new TypeError('config must be null, undefined, or an object');
 	}
 
-	config = { eventLoopMonitoringPrecision: 10, ...config };
+	config = { eventLoopMonitoringPrecision: 10, exclude: [], ...config };
 
-	for (const metric of Object.values(metrics)) {
-		metric(config.register, config);
+	for (const metricGroup of Object.keys(metrics)) {
+		if (config.exclude.includes(metricGroup)) {
+			continue;
+		}
+		metrics[metricGroup](config.register, config);
 	}
 };
 

test/defaultMetricsTest.js

@@ -105,6 +105,22 @@ describe.each([
 		});
 	});
 
+	it('should allow to exclude specific metrics', async () => {
+		expect(await register.getMetricsAsJSON()).toHaveLength(0);
+
+		collectDefaultMetrics();
+		expect(
+			await register.getSingleMetric('nodejs_eventloop_lag_seconds'),
+		).toBeDefined();
+
+		register.clear();
+
+		collectDefaultMetrics({ exclude: ['eventLoopLag'] });
+		expect(
+			await register.getSingleMetric('nodejs_eventloop_lag_seconds'),
+		).toBeUndefined();
+	});
+
 	describe('disabling', () => {
 		it('should not throw error', () => {
 			const fn = function () {