chore: added prometheus support in Etherpad

Author: SamTV12345

pnpm-lock.yaml

@@ -13,8 +13,11 @@ const plugins = require('../../../static/js/pluginfw/plugin_defs');
 
 import {build, buildSync} from 'esbuild'
 import {ArgsExpressType} from "../../types/ArgsExpressType";
+import prometheus from "../../prometheus";
+
 let ioI: { sockets: { sockets: any[]; }; } | null = null
 
+
 exports.socketio = (hookName: string, {io}: any) => {
   ioI = io
 }
@@ -35,6 +38,12 @@ exports.expressPreSession = async (hookName:string, {app}:ArgsExpressType) => {
     app.get('/stats', (req:any, res:any) => {
       res.json(require('../../stats').toJSON());
     });
+
+    app.get('/stats/prometheus', async (req, res) => {
+      const metrics = await prometheus()
+      res.setHeader('Content-Type', metrics.contentType)
+      res.send(await metrics.metrics())
+    })
   }
 
 

src/node/hooks/express/specialpages.ts

@@ -0,0 +1,11 @@
+import Prometheus from 'prom-client';
+
+export const metrics = {
+  'cpu': new Prometheus.Gauge({ name: 'nodejs_cpu_gauge', help: 'gauge for nodejs cpu' ,labelNames: ['type'] }),
+  'memory_process': new Prometheus.Gauge({ name: 'nodejs_memory_process_gauge', help: 'gauge for nodejs memory_process' ,labelNames: ['type'] }),
+  'memory_physical': new Prometheus.Gauge({ name: 'nodejs_memory_physical_gauge', help: 'gauge for nodejs_memory_physical' ,labelNames: ['type'] }),
+  'eventloop_latency':  new Prometheus.Gauge({ name: 'nodejs_eventloop_latency_gauge' , help: 'gauge for nodejs_eventloop_latency' ,labelNames: ['type'] }),
+  'gc': new Prometheus.Gauge({ name: 'nodejs_gc_gauge' , help: 'gause for nodejs_gc' ,labelNames: ['type']}),
+  'gc_duration': new Prometheus.Summary({ name: 'nodejs_gc_duration' , help: 'gause for nodejs_gc_duration', percentiles: [ 0.5, 0.75, 0.95 ] }),
+  'http_duration': new Prometheus.Summary({ name: 'http_duration', help: 'summary for http_duration', percentiles: [ 0.5, 0.75, 0.95 ] ,labelNames: ['url'] })
+};

src/node/metrics.ts

@@ -0,0 +1,25 @@
+import client from 'prom-client'
+const db = require('./db/DB').db
+
+const monitor = function () {
+  const collectDefaultMetrics = client.collectDefaultMetrics;
+  const Registry = client.Registry;
+  const register = new Registry();
+  collectDefaultMetrics({register});
+  const gaugeDB = new client.Gauge({
+    name: "ueberdb_stats",
+    help: "ueberdb stats",
+    labelNames: ['type'],
+  })
+
+  for (const [metric, value] of Object.entries(db.metrics)) {
+    if (typeof value !== 'number') continue;
+    gaugeDB.set({type: metric}, value);
+  }
+
+
+  register.registerMetric(gaugeDB);
+  return register
+};
+
+export default monitor;

src/node/prometheus.ts

@@ -58,6 +58,7 @@
     "mime-types": "^3.0.1",
     "oidc-provider": "^9.4.2",
     "openapi-backend": "^5.15.0",
+    "prom-client": "^15.1.3",
     "proxy-addr": "^2.0.7",
     "rate-limiter-flexible": "^7.2.0",
     "rehype": "^13.0.2",