feat(metrics): add MetricsModule with endpoint for Prometheus metrics

Author: maksberegovoi

libs/metrics/metrics.controller.ts

@@ -0,0 +1,13 @@
+import { Controller, Get, Header } from '@nestjs/common';
+import * as client from 'prom-client';
+import { SkipResponseValidation } from '@shared/decorators';
+
+@Controller()
+export class MetricsController {
+    @Get('dump')
+    @Header('Content-Type', client.register.contentType)
+    @SkipResponseValidation()
+    async getMetrics() {
+        return client.register.metrics();
+    }
+}

libs/metrics/metrics.module.ts

@@ -0,0 +1,17 @@
+import { Module } from '@nestjs/common';
+import { PrometheusModule } from '@willsoto/nestjs-prometheus';
+import { MetricsController } from './metrics.controller';
+
+@Module({
+    imports: [
+        PrometheusModule.registerAsync({
+            useFactory: () => ({
+                defaultMetrics: {
+                    enabled: process.env.NODE_ENV !== 'test',
+                },
+            }),
+        }),
+    ],
+    controllers: [MetricsController],
+})
+export class MetricsModule {}

package.json

@@ -77,6 +77,7 @@
         "passport": "^0.7.0",
         "passport-jwt": "^4.0.1",
         "postgres": "^3.4.9",
+        "prom-client": "^15.1.3",
         "reflect-metadata": "^0.2.0",
         "rxjs": "^7.8.1",
         "transliteration": "^2.6.1",

pnpm-lock.yaml

@@ -5,7 +5,6 @@ import { ConfigService } from '@nestjs/config';
 import * as schema from './shared/entities';
 import { APP_FILTER, APP_INTERCEPTOR, APP_PIPE } from '@nestjs/core';
 import { ZodValidationPipe } from 'nestjs-zod';
-import { PrometheusModule } from '@willsoto/nestjs-prometheus';
 import { HealthModule } from '@libs/health';
 import { UserModule } from './user';
 import { GlobalExceptionFilter } from '@shared/error';
@@ -24,18 +23,12 @@ import { CACHE_SERVICE } from '@shared/adapters/cache/constants';
 import { ICacheService } from '@shared/adapters/cache/ports';
 import { DatabaseHealthService } from '@libs/database';
 import { ZodValidationInterceptor } from '@shared/interceptors/zod-validation.interceptor';
+import { MetricsModule } from '../libs/metrics/metrics.module';
 
 @Module({
     imports: [
         ConfigModule,
-        PrometheusModule.registerAsync({
-            useFactory: () => ({
-                path: 'dump',
-                defaultMetrics: {
-                    enabled: process.env.NODE_ENV !== 'test',
-                },
-            }),
-        }),
+        MetricsModule,
         DatabaseModule.registerAsync({
             global: true,
             inject: [ConfigService],