✨ Add metrics module (#1142)

src/modules/metrics/metrics.controller.ts

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+import { Controller, Get, Post } from '@nestjs/common';
+import { Scopes } from '../auth/scope.decorator';
+import { ProcessMetricData } from './metrics.interface';
+import { MetricsService } from './metrics.service';
+
+@Controller('metrics')
+export class MetricsController {
+  constructor(private metricsService: MetricsService) {}
+
+  /** Get process metrics */
+  @Get('process')
+  @Scopes('metric:read-process')
+  process(): Promise<ProcessMetricData[]> {
+    return this.metricsService.getProcessMetrics();
+  }
+
+  /** Update metrics */
+  @Post('update')
+  @Scopes('metric:write-process')
+  update(): Promise<ProcessMetricData[]> {
+    return this.metricsService.updateProcessMetrics();
+  }
+}

src/modules/metrics/metrics.interface.ts

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+export interface ProcessMetricData {
+  date: Date;
+  cpu: number;
+  memory: number;
+}

src/modules/metrics/metrics.module.ts

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+import { Module } from '@nestjs/common';
+import { PrismaModule } from '../../providers/prisma/prisma.module';
+import { MetricsController } from './metrics.controller';
+import { MetricsService } from './metrics.service';
+
+@Module({
+  imports: [PrismaModule],
+  controllers: [MetricsController],
+  providers: [MetricsService],
+  exports: [MetricsService],
+})
+export class MetricsModule {}

src/modules/metrics/metrics.service.ts

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+import { Injectable } from '@nestjs/common';
+import CircularBuffer from 'circularbuffer';
+import pidusage from 'pidusage';
+import { PrismaService } from '../../providers/prisma/prisma.service';
+import type { ProcessMetricData } from './metrics.interface';
+
+@Injectable()
+export class MetricsService {
+  private queue = new CircularBuffer<ProcessMetricData>(60);
+
+  constructor(private prisma: PrismaService) {}
+
+  async updateProcessMetrics(): Promise<ProcessMetricData[]> {
+    const stats = await pidusage(process.pid);
+    this.queue.enq({
+      date: new Date(),
+      cpu: Math.round(stats.cpu * 100) / 100,
+      memory: Math.round(stats.memory * 100) / 100,
+    });
+    return this.getProcessMetrics();
+  }
+
+  async getProcessMetrics(): Promise<ProcessMetricData[]> {
+    return this.queue.toArray();
+  }
+}