health.controller.ts

import { Body, Controller, Get, Post } from '@nestjs/common';
import {
  HealthCheck,
  HealthCheckService,
  MemoryHealthIndicator,
} from '@nestjs/terminus';
import { PingDto } from './dto/ping.dto';

/**
 * Exposes the `/health` endpoint used by orchestrators and uptime monitors to
 * determine whether the service is alive and ready to serve traffic.
 */
@Controller('health')
export class HealthController {
  constructor(
    private readonly health: HealthCheckService,
    private readonly memory: MemoryHealthIndicator,
  ) {}

  @Get()
  @HealthCheck()
  check() {
    // Threshold has headroom above a bare ts-jest/Nest test process's own
    // baseline heap (~270MB before the app does anything), so this check
    // stays meaningful in prod without flaking in CI.
    return this.health.check([
      () => this.memory.checkHeap('memory_heap', 512 * 1024 * 1024),
    ]);
  }

  /**
   * Trivial endpoint whose sole purpose is to exercise the global
   * ValidationPipe against a real DTO (whitelist/forbidNonWhitelisted/transform).
   */
  @Post('ping')
  ping(@Body() body: PingDto) {
    return { echo: body.message };
  }
}