feat(core): Add metrics option to cache (#6846)

* add metrics to cache

* use events for metrics

* pr comments / broken test

* lint fix

* update the test

* improve tests

* Update packages/cli/src/config/schema.ts

* disable flaky test

* lint fix

---------

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>
Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <netroy@users.noreply.github.com>

packages/cli/src/metrics/index.ts

@@ -1,71 +0,0 @@
-/* eslint-disable @typescript-eslint/no-use-before-define */
-import config from '@/config';
-import { N8N_VERSION } from '@/constants';
-import * as ResponseHelper from '@/ResponseHelper';
-import type express from 'express';
-import promBundle from 'express-prom-bundle';
-import promClient from 'prom-client';
-import semverParse from 'semver/functions/parse';
-
-export { promClient };
-
-export function configureMetrics(app: express.Application) {
-	if (!config.getEnv('endpoints.metrics.enable')) {
-		return;
-	}
-
-	setupDefaultMetrics();
-	setupN8nVersionMetric();
-	setupApiMetrics(app);
-	mountMetricsEndpoint(app);
-}
-
-function setupN8nVersionMetric() {
-	const n8nVersion = semverParse(N8N_VERSION || '0.0.0');
-
-	if (n8nVersion) {
-		const versionGauge = new promClient.Gauge({
-			name: config.getEnv('endpoints.metrics.prefix') + 'version_info',
-			help: 'n8n version info.',
-			labelNames: ['version', 'major', 'minor', 'patch'],
-		});
-
-		versionGauge.set(
-			{
-				version: 'v' + n8nVersion.version,
-				major: n8nVersion.major,
-				minor: n8nVersion.minor,
-				patch: n8nVersion.patch,
-			},
-			1,
-		);
-	}
-}
-
-function setupDefaultMetrics() {
-	if (config.getEnv('endpoints.metrics.includeDefaultMetrics')) {
-		promClient.collectDefaultMetrics();
-	}
-}
-
-function setupApiMetrics(app: express.Application) {
-	if (config.getEnv('endpoints.metrics.includeApiEndpoints')) {
-		const metricsMiddleware = promBundle({
-			autoregister: false,
-			includeUp: false,
-			includePath: config.getEnv('endpoints.metrics.includeApiPathLabel'),
-			includeMethod: config.getEnv('endpoints.metrics.includeApiMethodLabel'),
-			includeStatusCode: config.getEnv('endpoints.metrics.includeApiStatusCodeLabel'),
-		});
-
-		app.use(['/rest/', '/webhook/', 'webhook-test/', '/api/'], metricsMiddleware);
-	}
-}
-
-function mountMetricsEndpoint(app: express.Application) {
-	app.get('/metrics', async (req: express.Request, res: express.Response) => {
-		const response = await promClient.register.metrics();
-		res.setHeader('Content-Type', promClient.register.contentType);
-		ResponseHelper.sendSuccessResponse(res, response, true, 200);
-	});
-}