Use prometheus exporter instead of manual endpoint

Author: thomtrp

packages/twenty-server/package.json

@@ -65,6 +65,7 @@
     "@opentelemetry/api": "^1.9.0",
     "@opentelemetry/auto-instrumentations-node": "^0.60.0",
     "@opentelemetry/exporter-metrics-otlp-http": "^0.200.0",
+    "@opentelemetry/exporter-prometheus": "^0.211.0",
     "@opentelemetry/sdk-metrics": "^2.0.0",
     "@opentelemetry/sdk-node": "^0.202.0",
     "@ptc-org/nestjs-query-core": "4.4.0",
@@ -157,7 +158,6 @@
     "planer": "1.2.0",
     "pluralize": "8.0.0",
     "postal-mime": "^2.6.1",
-    "prom-client": "^15.1.3",
     "psl": "^1.9.0",
     "react": "18.3.1",
     "react-dom": "18.3.1",

packages/twenty-server/src/engine/core-modules/metrics/metrics.module.ts

@@ -2,12 +2,9 @@ import { Module } from '@nestjs/common';
 
 import { MetricsCacheService } from 'src/engine/core-modules/metrics/metrics-cache.service';
 import { MetricsService } from 'src/engine/core-modules/metrics/metrics.service';
-import { PrometheusController } from 'src/engine/core-modules/metrics/prometheus.controller';
-import { PrometheusService } from 'src/engine/core-modules/metrics/prometheus.service';
 
 @Module({
-  controllers: [PrometheusController],
-  providers: [MetricsService, MetricsCacheService, PrometheusService],
-  exports: [MetricsService, MetricsCacheService, PrometheusService],
+  providers: [MetricsService, MetricsCacheService],
+  exports: [MetricsService, MetricsCacheService],
 })
 export class MetricsModule {}

packages/twenty-server/src/engine/core-modules/metrics/prometheus.controller.ts

@@ -1,4 +1,5 @@
 export enum MeterDriver {
   OpenTelemetry = 'opentelemetry',
   Console = 'console',
+  Prometheus = 'prometheus',
 }

packages/twenty-server/src/engine/core-modules/metrics/prometheus.service.spec.ts

@@ -1,5 +1,6 @@
 import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
 
+import { metrics } from '@opentelemetry/api';
 import { type RecordGqlOperationSignature } from 'twenty-shared/types';
 import { isDefined } from 'twenty-shared/utils';
 
@@ -9,7 +10,6 @@ import { WithLock } from 'src/engine/core-modules/cache-lock/with-lock.decorator
 import { InjectCacheStorage } from 'src/engine/core-modules/cache-storage/decorators/cache-storage.decorator';
 import { CacheStorageService } from 'src/engine/core-modules/cache-storage/services/cache-storage.service';
 import { CacheStorageNamespace } from 'src/engine/core-modules/cache-storage/types/cache-storage-namespace.enum';
-import { PrometheusService } from 'src/engine/core-modules/metrics/prometheus.service';
 import { EVENT_STREAM_TTL_MS } from 'src/engine/subscriptions/constants/event-stream-ttl.constant';
 import {
   EventStreamException,
@@ -25,22 +25,26 @@ export class EventStreamService implements OnModuleInit {
     @InjectCacheStorage(CacheStorageNamespace.EngineSubscriptions)
     private readonly cacheStorageService: CacheStorageService,
     private readonly cacheLockService: CacheLockService,
-    private readonly prometheusService: PrometheusService,
   ) {}
 
   onModuleInit() {
-    this.prometheusService.createGauge({
-      name: 'twenty_event_streams_live_total',
-      help: 'Current number of live event streams',
-      collect: async (gauge) => {
-        try {
-          const count = await this.getTotalActiveStreamCount();
-
-          gauge.set(count);
-        } catch (error) {
-          this.logger.error('Failed to collect event streams metrics', error);
-        }
+    const meter = metrics.getMeter('twenty-server');
+
+    const gauge = meter.createObservableGauge(
+      'twenty_event_streams_live_total',
+      {
+        description: 'Current number of live event streams',
       },
+    );
+
+    gauge.addCallback(async (observableResult) => {
+      try {
+        const count = await this.getTotalActiveStreamCount();
+
+        observableResult.observe(count);
+      } catch (error) {
+        this.logger.error('Failed to collect event streams metrics', error);
+      }
     });
   }
 

packages/twenty-server/src/engine/core-modules/metrics/prometheus.service.ts

@@ -3,7 +3,6 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 
 import { CacheLockModule } from 'src/engine/core-modules/cache-lock/cache-lock.module';
 import { CacheStorageModule } from 'src/engine/core-modules/cache-storage/cache-storage.module';
-import { MetricsModule } from 'src/engine/core-modules/metrics/metrics.module';
 import { RedisClientModule } from 'src/engine/core-modules/redis-client/redis-client.module';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
 import { EventStreamService } from 'src/engine/subscriptions/event-stream.service';
@@ -14,7 +13,6 @@ import { SubscriptionService } from 'src/engine/subscriptions/subscription.servi
     RedisClientModule,
     CacheStorageModule,
     CacheLockModule,
-    MetricsModule,
     TypeOrmModule.forFeature([WorkspaceEntity]),
   ],
   providers: [SubscriptionService, EventStreamService],

packages/twenty-server/src/engine/core-modules/metrics/types/meter-driver.type.ts

@@ -2,6 +2,7 @@ import process from 'process';
 
 import opentelemetry from '@opentelemetry/api';
 import { OTLPMetricExporter } from '@opentelemetry/exporter-metrics-otlp-http';
+import { PrometheusExporter } from '@opentelemetry/exporter-prometheus';
 import {
   AggregationTemporality,
   ConsoleMetricExporter,
@@ -49,6 +50,11 @@ if (process.env.EXCEPTION_HANDLER_DRIVER === ExceptionHandlerDriver.SENTRY) {
 
 // Meter setup
 
+// PrometheusExporter starts its own HTTP server on port 9464
+const prometheusExporter = meterDrivers.includes(MeterDriver.Prometheus)
+  ? new PrometheusExporter({ port: 9464 })
+  : null;
+
 const meterProvider = new MeterProvider({
   readers: [
     ...(meterDrivers.includes(MeterDriver.Console)
@@ -70,6 +76,7 @@ const meterProvider = new MeterProvider({
           }),
         ]
       : []),
+    ...(prometheusExporter ? [prometheusExporter] : []),
   ],
 });