feat(metrics): implement ability to collect default prometheus metrics

Add configuration option `collectDefaultMetrics` that when set to `true` will enable the plugin to
collect default prometheus client metrics (e.g. cpu/ram)

fix #4

README.md

@@ -31,6 +31,10 @@ middlewares:
     ## Optional. Defaults to `false` so make sure to set this to `true` if you want to collect metrics.
     metricsEnabled: true
 
+    ## Optional. Collect default prometheus metrics. Defaults to `false`.
+    ## Refer to: https://github.com/siimon/prom-client/tree/v14.0.1#default-metrics
+    collectDefaultMetrics: false
+
     ## Optional. Defaults to `/-/metrics`.
     metricsPath: /custom/path/metrics
 

src/metrics.ts

@@ -1,4 +1,4 @@
-import { register, Counter } from 'prom-client';
+import { collectDefaultMetrics, register, Counter } from 'prom-client';
 import { Logger, IPluginMiddleware, IBasicAuth, IStorageManager, PluginOptions } from '@verdaccio/types';
 import { Request, Response, NextFunction, Application } from 'express';
 
@@ -22,14 +22,16 @@ export const REQUEST_COUNTER_OPTIONS = {
 export default class VerdaccioMiddlewarePlugin implements IPluginMiddleware<MetricsConfig> {
   public logger: Logger;
   public metricsEnabled: boolean;
+  public collectDefaultMetrics: boolean;
   public metricsPath: string;
   public packageGroups: Record<string, string>;
   private requestsCounter = new Counter(REQUEST_COUNTER_OPTIONS);
 
   public constructor(config: MetricsConfig, options: PluginOptions<MetricsConfig>) {
     this.metricsEnabled = [true, 'true'].includes(config.metricsEnabled);
+    this.collectDefaultMetrics = [true, 'true'].includes(config.collectDefaultMetrics);
     this.metricsPath = config.metricsPath || '/-/metrics';
-    this.packageGroups = config.packageGroups || [];
+    this.packageGroups = config.packageGroups || {};
     this.logger = options.logger;
   }
 
@@ -48,6 +50,9 @@ export default class VerdaccioMiddlewarePlugin implements IPluginMiddleware<Metr
       this.logger.info(`metrics: [register_middlewares] metrics are enabled and exposed at '${this.metricsPath}'`);
       app.get(/.*[.]tgz$/i, this.collectMetrics.bind(this));
       app.get(this.metricsPath, this.getMetrics.bind(this));
+      if (this.collectDefaultMetrics) {
+        collectDefaultMetrics();
+      }
     } else {
       this.logger.warn('metrics: [register_middlewares] metrics are disabled');
     }

src/types/index.ts

@@ -2,6 +2,7 @@ import { Config } from '@verdaccio/types';
 
 export interface MetricsConfig extends Config {
   metricsEnabled: boolean;
+  collectDefaultMetrics: boolean;
   metricsPath: string;
   packageGroups: Record<string, string>;
 }

tests/metrics.spec.ts

@@ -208,4 +208,56 @@ describe('Metrics Plugin', () => {
       );
     });
   });
+
+  describe('should collect default prometheus metrics when `collectDefaultMetrics` is set to `true`', () => {
+    const { req, res, next } = getExpressMocks();
+    const app = { get: jest.fn() } as unknown as Application;
+
+    beforeAll(() => {
+      register.clear();
+      const metricsPlugin = new MetricsPlugin(
+        { metricsEnabled: true, collectDefaultMetrics: true } as MetricsConfig,
+        { logger: getLogger() } as PluginOptions<MetricsConfig>
+      );
+      metricsPlugin.register_middlewares(app, {} as IBasicAuth<MetricsConfig>, {} as IStorageManager<MetricsConfig>);
+      metricsPlugin.collectMetrics(req, res, next);
+      metricsPlugin.getMetrics(req, res);
+    });
+
+    test('should collect default prometheus metrics', async () => {
+      const metrics = await register.getMetricsAsJSON();
+      expect(metrics.map(({ name }) => name).sort()).toEqual([
+        'nodejs_active_handles',
+        'nodejs_active_handles_total',
+        'nodejs_active_requests',
+        'nodejs_active_requests_total',
+        'nodejs_eventloop_lag_max_seconds',
+        'nodejs_eventloop_lag_mean_seconds',
+        'nodejs_eventloop_lag_min_seconds',
+        'nodejs_eventloop_lag_p50_seconds',
+        'nodejs_eventloop_lag_p90_seconds',
+        'nodejs_eventloop_lag_p99_seconds',
+        'nodejs_eventloop_lag_seconds',
+        'nodejs_eventloop_lag_stddev_seconds',
+        'nodejs_external_memory_bytes',
+        'nodejs_gc_duration_seconds',
+        'nodejs_heap_size_total_bytes',
+        'nodejs_heap_size_used_bytes',
+        'nodejs_heap_space_size_available_bytes',
+        'nodejs_heap_space_size_total_bytes',
+        'nodejs_heap_space_size_used_bytes',
+        'nodejs_version_info',
+        'process_cpu_seconds_total',
+        'process_cpu_system_seconds_total',
+        'process_cpu_user_seconds_total',
+        'process_heap_bytes',
+        'process_max_fds',
+        'process_open_fds',
+        'process_resident_memory_bytes',
+        'process_start_time_seconds',
+        'process_virtual_memory_bytes',
+        'registry_requests',
+      ]);
+    });
+  });
 });