feat: add metrics

compose.yml

@@ -9,6 +9,8 @@ services:
     restart: always
     env_file:
       - .env.production.local
+    expose:
+      - '9102'
     networks:
       - teacinema
 

package.json

@@ -30,11 +30,13 @@
     "@nestjs/platform-express": "^11.0.1",
     "@teacinema/contracts": "^1.1.0",
     "@teacinema/core": "^1.0.9",
+    "@willsoto/nestjs-prometheus": "^6.0.2",
     "amqp-connection-manager": "^5.0.0",
     "amqplib": "^0.10.9",
     "axios": "^1.13.5",
     "cross-env": "^10.1.0",
     "handlebars": "^4.7.8",
+    "prom-client": "^15.1.3",
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.1",
     "zod": "^4.3.6"

src/app.module.ts

@@ -6,6 +6,7 @@ import { MailModule } from './infra/mail/mail.module'
 import { RmqModule } from './infra/rmq/rmq.module'
 import { SmsModule } from './infra/sms/sms.module'
 import { NotificationsModule } from './modules/notifications/notifications.module'
+import { ObservabilityModule } from './observability/observability.module'
 
 @Module({
   imports: [
@@ -20,6 +21,7 @@ import { NotificationsModule } from './modules/notifications/notifications.modul
       ]
     }),
     RmqModule,
+    ObservabilityModule,
     NotificationsModule,
     MailModule,
     SmsModule

src/infra/rmq/rmq.service.ts

@@ -1,11 +1,21 @@
 import { Injectable, Logger } from '@nestjs/common'
 import { RmqContext } from '@nestjs/microservices'
+import { InjectMetric } from '@willsoto/nestjs-prometheus'
+import { Counter } from 'prom-client'
 
 @Injectable()
 export class RmqService {
+  private readonly SERVICE_NAME = 'notification-service'
   private logger = new Logger(RmqService.name)
 
-  public ack(context: RmqContext) {
+  public constructor(
+    @InjectMetric('rmq_events_ack_total')
+    private readonly ackTotal: Counter<string>,
+    @InjectMetric('rmq_events_nack_total')
+    private readonly nackTotal: Counter<string>
+  ) {}
+
+  public ack(context: RmqContext, event: string) {
     const channel = context.getChannelRef()
     const msg = context.getMessage()
     const tag = msg?.fields?.deliveryTag
@@ -14,11 +24,16 @@ export class RmqService {
       return
     }
 
+    this.ackTotal.inc({
+      service: this.SERVICE_NAME,
+      event
+    })
+
     channel.ack(msg)
     this.logger.debug(`ACK (pattern: ${context.getPattern()}, tag: ${tag}): }`)
   }
 
-  public nack(context: RmqContext, requeue = false) {
+  public nack(context: RmqContext, event: string, requeue = false) {
     const channel = context.getChannelRef()
     const msg = context.getMessage()
     const tag = msg?.fields?.deliveryTag
@@ -28,6 +43,12 @@ export class RmqService {
     }
 
     channel.nack(msg, false, requeue)
+
+    this.nackTotal.inc({
+      service: this.SERVICE_NAME,
+      event
+    })
+
     if (requeue) {
       this.logger.warn(
         `NACK response (pattern: ${context.getPattern()}, tag: ${tag}): }`

src/main.ts

@@ -24,6 +24,6 @@ async function bootstrap() {
   })
 
   await app.startAllMicroservices()
-  await app.init()
+  await app.listen(9102)
 }
 bootstrap()

src/modules/notifications/notifications.controller.ts

@@ -5,6 +5,8 @@ import type {
   OtpRequestedEvent,
   PhoneChangedEvent
 } from '@teacinema/contracts'
+import { InjectMetric } from '@willsoto/nestjs-prometheus'
+import { Counter, Histogram } from 'prom-client'
 
 import { RmqService } from '../../infra/rmq/rmq.service'
 
@@ -12,11 +14,16 @@ import { NotificationsService } from './notifications.service'
 
 @Controller()
 export class NotificationsController {
+  private readonly SERVICE_NAME = 'notification-service'
   private readonly logger = new Logger(NotificationsController.name)
 
   constructor(
     private readonly notificationsService: NotificationsService,
-    private readonly rmqService: RmqService
+    private readonly rmqService: RmqService,
+    @InjectMetric('rmq_event_processing_duration_seconds')
+    private readonly processingDuration: Histogram<string>,
+    @InjectMetric('rmq_events_total')
+    private readonly eventsTotal: Counter<string>
   ) {}
 
   @EventPattern('auth.otp.requested')
@@ -24,12 +31,32 @@ export class NotificationsController {
     @Payload() data: OtpRequestedEvent,
     @Ctx() ctx: RmqContext
   ) {
+    const event = 'auth.otp.requested'
+    const endTimer = this.processingDuration.startTimer({
+      service: this.SERVICE_NAME,
+      event
+    })
+
     try {
       await this.notificationsService.sendOtp(data)
-      this.rmqService.ack(ctx)
+
+      this.eventsTotal.inc({
+        service: this.SERVICE_NAME,
+        event,
+        status: 'success'
+      })
+
+      this.rmqService.ack(ctx, event)
     } catch (e) {
+      this.eventsTotal.inc({
+        service: this.SERVICE_NAME,
+        event,
+        status: 'error'
+      })
       this.logger.error(`OTP processing error ${e.message ?? e}}`)
-      this.rmqService.nack(ctx)
+      this.rmqService.nack(ctx, event)
+    } finally {
+      endTimer()
     }
   }
 
@@ -38,12 +65,30 @@ export class NotificationsController {
     @Payload() data: PhoneChangedEvent,
     @Ctx() ctx: RmqContext
   ) {
+    const event = 'account.phone.changed'
+    const endTimer = this.processingDuration.startTimer({
+      service: this.SERVICE_NAME,
+      event
+    })
+
     try {
       await this.notificationsService.phoneChanged(data)
-      this.rmqService.ack(ctx)
+      this.eventsTotal.inc({
+        service: this.SERVICE_NAME,
+        event,
+        status: 'success'
+      })
+      this.rmqService.ack(ctx, event)
     } catch (e) {
+      this.eventsTotal.inc({
+        service: this.SERVICE_NAME,
+        event,
+        status: 'error'
+      })
       this.logger.error(`Phone changing processing error ${e.message ?? e}}`)
-      this.rmqService.nack(ctx)
+      this.rmqService.nack(ctx, event)
+    } finally {
+      endTimer()
     }
   }
 
@@ -52,12 +97,30 @@ export class NotificationsController {
     @Payload() data: EmailChangedEvent,
     @Ctx() ctx: RmqContext
   ) {
+    const event = 'account.email.changed'
+    const endTimer = this.processingDuration.startTimer({
+      service: this.SERVICE_NAME,
+      event
+    })
+
     try {
       await this.notificationsService.emailChanged(data)
-      this.rmqService.ack(ctx)
+      this.eventsTotal.inc({
+        service: this.SERVICE_NAME,
+        event,
+        status: 'success'
+      })
+      this.rmqService.ack(ctx, event)
     } catch (e) {
+      this.eventsTotal.inc({
+        service: this.SERVICE_NAME,
+        event,
+        status: 'error'
+      })
       this.logger.error(`Email changing processing error ${e.message ?? e}}`)
-      this.rmqService.nack(ctx)
+      this.rmqService.nack(ctx, event)
+    } finally {
+      endTimer()
     }
   }
 }

src/observability/metrics/metrics.module.ts

@@ -0,0 +1,48 @@
+import { Global, Module } from '@nestjs/common'
+import {
+  makeCounterProvider,
+  makeHistogramProvider,
+  PrometheusModule
+} from '@willsoto/nestjs-prometheus'
+
+@Global()
+@Module({
+  imports: [
+    PrometheusModule.register({
+      path: '/metrics',
+      defaultMetrics: {
+        enabled: true
+      }
+    })
+  ],
+  providers: [
+    makeHistogramProvider({
+      name: 'rmq_event_processing_duration_seconds',
+      help: 'RabbitMQ event processing duration',
+      labelNames: ['service', 'event'],
+      buckets: [0.05, 0.1, 0.2, 0.5, 1, 2, 5]
+    }),
+    makeCounterProvider({
+      name: 'rmq_events_total',
+      help: 'Total RMQ events processed',
+      labelNames: ['service', 'event', 'status']
+    }),
+    makeCounterProvider({
+      name: 'rmq_events_ack_total',
+      help: 'Total ACKed RMQ events',
+      labelNames: ['service', 'event']
+    }),
+    makeCounterProvider({
+      name: 'rmq_events_nack_total',
+      help: 'Total NACKed RMQ events',
+      labelNames: ['service', 'event']
+    })
+  ],
+  exports: [
+    'PROM_METRIC_RMQ_EVENT_PROCESSING_DURATION_SECONDS',
+    'PROM_METRIC_RMQ_EVENTS_TOTAL',
+    'PROM_METRIC_RMQ_EVENTS_ACK_TOTAL',
+    'PROM_METRIC_RMQ_EVENTS_NACK_TOTAL'
+  ]
+})
+export class MetricsModule {}

src/observability/observability.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common'
+
+import { MetricsModule } from './metrics/metrics.module'
+
+@Module({
+  imports: [MetricsModule]
+})
+export class ObservabilityModule {}

yarn.lock

@@ -1150,6 +1150,11 @@
   resolved "https://registry.yarnpkg.com/@one-ini/wasm/-/wasm-0.1.1.tgz#6013659736c9dbfccc96e8a9c2b3de317df39323"
   integrity sha512-XuySG1E38YScSJoMlqovLru4KTUNSjgVTIjyh7qMX6aNN5HY5Ct5LhRJdxO79JtTzKfzV/bnWpz+zquYrISsvw==
 
+"@opentelemetry/api@^1.4.0":
+  version "1.9.0"
+  resolved "https://registry.yarnpkg.com/@opentelemetry/api/-/api-1.9.0.tgz#d03eba68273dc0f7509e2a3d5cba21eae10379fe"
+  integrity sha512-3giAOQvZiH5F9bMlMiv8+GSPMeqg0dbaeo58/0SlA9sxSqZhnUtxzX9/2FzyhS9sWQf5S0GJE0AKBrFqjpeYcg==
+
 "@paralleldrive/cuid2@^2.2.2":
   version "2.3.1"
   resolved "https://registry.yarnpkg.com/@paralleldrive/cuid2/-/cuid2-2.3.1.tgz#3d62ea9e7be867d3fa94b9897fab5b0ae187d784"
@@ -1813,6 +1818,11 @@
     "@webassemblyjs/ast" "1.14.1"
     "@xtuc/long" "4.2.2"
 
+"@willsoto/nestjs-prometheus@^6.0.2":
+  version "6.0.2"
+  resolved "https://registry.yarnpkg.com/@willsoto/nestjs-prometheus/-/nestjs-prometheus-6.0.2.tgz#d603764a923848442ed092411716c0bf211de01f"
+  integrity sha512-ePyLZYdIrOOdlOWovzzMisIgviXqhPVzFpSMKNNhn6xajhRHeBsjAzSdpxZTc6pnjR9hw1lNAHyKnKl7lAPaVg==
+
 "@xtuc/ieee754@^1.2.0":
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/@xtuc/ieee754/-/ieee754-1.2.0.tgz#eef014a3145ae477a1cbc00cd1e552336dceb790"
@@ -2151,6 +2161,11 @@ binary-extensions@^2.0.0:
   resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-2.3.0.tgz#f6e14a97858d327252200242d4ccfe522c445522"
   integrity sha512-Ceh+7ox5qe7LJuLHoY0feh3pHuUDHAcRUeyL2VYghZwfpkNIy/+8Ocg0a3UuSoYzavmylwuLWQOf3hl0jjMMIw==
 
+bintrees@1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/bintrees/-/bintrees-1.0.2.tgz#49f896d6e858a4a499df85c38fb399b9aff840f8"
+  integrity sha512-VOMgTMwjAaUG580SXn3LacVgjurrbMme7ZZNYGSSV7mmtY6QQRh0Eg3pwIcntQ77DErK1L0NxkbetjcoXzVwKw==
+
 bl@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/bl/-/bl-4.1.0.tgz#451535264182bec2fbbc83a62ab98cf11d9f7b3a"
@@ -5509,6 +5524,14 @@ preview-email@^3.0.19:
     pug "^3.0.3"
     uuid "^9.0.1"
 
+prom-client@^15.1.3:
+  version "15.1.3"
+  resolved "https://registry.yarnpkg.com/prom-client/-/prom-client-15.1.3.tgz#69fa8de93a88bc9783173db5f758dc1c69fa8fc2"
+  integrity sha512-6ZiOBfCywsD4k1BN9IX0uZhF+tJkV8q8llP64G5Hajs4JOeVLPCwpPVcpXy3BwYiUGgyJzsJJQeOIv7+hDSq8g==
+  dependencies:
+    "@opentelemetry/api" "^1.4.0"
+    tdigest "^0.1.1"
+
 promise-breaker@^6.0.0:
   version "6.0.0"
   resolved "https://registry.yarnpkg.com/promise-breaker/-/promise-breaker-6.0.0.tgz#107d2b70f161236abdb4ac5a736c7eb8df489d0f"
@@ -6210,6 +6233,13 @@ tapable@^2.2.1, tapable@^2.3.0:
   resolved "https://registry.yarnpkg.com/tapable/-/tapable-2.3.0.tgz#7e3ea6d5ca31ba8e078b560f0d83ce9a14aa8be6"
   integrity sha512-g9ljZiwki/LfxmQADO3dEY1CbpmXT5Hm2fJ+QaGKwSXUylMybePR7/67YW7jOrrvjEgL1Fmz5kzyAjWVWLlucg==
 
+tdigest@^0.1.1:
+  version "0.1.2"
+  resolved "https://registry.yarnpkg.com/tdigest/-/tdigest-0.1.2.tgz#96c64bac4ff10746b910b0e23b515794e12faced"
+  integrity sha512-+G0LLgjjo9BZX2MfdvPfH+MKLCrxlXSYec5DaPYP1fe6Iyhf0/fSmJ0bFiZ1F8BT6cGXl2LpltQptzjXKWEkKA==
+  dependencies:
+    bintrees "1.0.2"
+
 terser-webpack-plugin@^5.3.16:
   version "5.3.16"
   resolved "https://registry.yarnpkg.com/terser-webpack-plugin/-/terser-webpack-plugin-5.3.16.tgz#741e448cc3f93d8026ebe4f7ef9e4afacfd56330"