Prometheus metrics

src/app.module.ts

@@ -22,6 +22,7 @@ import { VodsRepository } from './vods/vods.repository';
 import { ChannelsRepository } from './channels/channels.repository';
 import { UsersRepository } from './users/users.repository';
 import { ScheduleModule } from '@nestjs/schedule';
+import { MetricsModule } from './metrics/metrics.module';
 
 @Module({
   imports: [
@@ -81,6 +82,8 @@ import { ScheduleModule } from '@nestjs/schedule';
     ExecModule,
 
     ScheduleModule.forRoot(),
+
+    MetricsModule,
   ],
   controllers: [AppController],
   providers: [

src/metrics/metrics.controller.spec.ts

@@ -0,0 +1,20 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { MetricsController } from './metrics.controller';
+import { MetricsService } from './metrics.service';
+
+describe('MetricsController', () => {
+  let controller: MetricsController;
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      controllers: [MetricsController],
+      providers: [MetricsService],
+    }).compile();
+
+    controller = module.get<MetricsController>(MetricsController);
+  });
+
+  it('should be defined', () => {
+    expect(controller).toBeDefined();
+  });
+});

src/metrics/metrics.controller.ts

@@ -0,0 +1,12 @@
+import { Controller, Get } from '@nestjs/common';
+import { MetricsService } from './metrics.service';
+
+@Controller('metrics')
+export class MetricsController {
+  constructor(private readonly metricsService: MetricsService) {}
+
+  @Get()
+  getMetrics(): Promise<any> {
+    return this.metricsService.getMetrics();
+  }
+}

src/metrics/metrics.module.ts

@@ -0,0 +1,20 @@
+import { Module } from '@nestjs/common';
+import { MetricsService } from './metrics.service';
+import { MetricsController } from './metrics.controller';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { VodsRepository } from 'src/vods/vods.repository';
+import { QueuesRepository } from 'src/queues/queues.repository';
+import { ChannelsRepository } from 'src/channels/channels.repository';
+
+@Module({
+  imports: [
+    TypeOrmModule.forFeature([
+      VodsRepository,
+      QueuesRepository,
+      ChannelsRepository,
+    ]),
+  ],
+  controllers: [MetricsController],
+  providers: [MetricsService],
+})
+export class MetricsModule {}

src/metrics/metrics.service.spec.ts

@@ -0,0 +1,18 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { MetricsService } from './metrics.service';
+
+describe('MetricsService', () => {
+  let service: MetricsService;
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [MetricsService],
+    }).compile();
+
+    service = module.get<MetricsService>(MetricsService);
+  });
+
+  it('should be defined', () => {
+    expect(service).toBeDefined();
+  });
+});

src/metrics/metrics.service.ts

@@ -0,0 +1,50 @@
+import {
+  Injectable,
+  InternalServerErrorException,
+  Logger,
+} from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { ChannelsRepository } from 'src/channels/channels.repository';
+import { QueuesRepository } from 'src/queues/queues.repository';
+import { VodsRepository } from 'src/vods/vods.repository';
+
+@Injectable()
+export class MetricsService {
+  private logger = new Logger('MetricsService');
+
+  constructor(
+    @InjectRepository(ChannelsRepository)
+    private readonly channelsRepository: ChannelsRepository,
+    @InjectRepository(QueuesRepository)
+    private readonly queuesRepository: QueuesRepository,
+    @InjectRepository(VodsRepository)
+    private readonly vodsRepository: VodsRepository,
+  ) {}
+  async getMetrics() {
+    try {
+      const vodCount = await this.vodsRepository
+        .createQueryBuilder('vods')
+        .getCount();
+      const channelCount = await this.channelsRepository
+        .createQueryBuilder('channels')
+        .getCount();
+      const channels = await this.channelsRepository
+        .createQueryBuilder('channel')
+        .loadRelationCountAndMap('channel.vodCount', 'channel.vods', 'vod')
+        .getMany();
+
+      let channelsString = '';
+
+      for await (const channel of channels) {
+        channelsString += `channel_vod_count{id="${channel.displayName}"} ${channel['vodCount']}\n`;
+      }
+
+      const metrics =
+        `vod_count{id="ceres"} ${vodCount}\nchannel_count{id="ceres"} ${channelCount}\n${channelsString}`.toString();
+      return metrics;
+    } catch (error) {
+      this.logger.error(error);
+      throw new InternalServerErrorException('Error fetching metrics');
+    }
+  }
+}