NestJS

Setup

instrumentation.ts

import { init } from 'autotel';

init({
  service: 'my-nestjs-api',
  autoInstrumentations: ['http', 'nestjs-core'],
  endpoint: process.env.OTLP_ENDPOINT,
});

Run with:

tsx --import ./instrumentation.ts src/main.ts

Tracing Services

Use trace() inside NestJS services for business logic spans:

import { Injectable } from '@nestjs/common';
import { trace, type TraceContext } from 'autotel';

@Injectable()
export class UserService {
  private readonly tracedFetchUser = trace(
    (ctx: TraceContext) => async (userId: string) => {
      ctx.setAttribute('db.query', 'SELECT * FROM users WHERE id = ?');
      ctx.setAttribute('db.userId', userId);
      return await this.prisma.user.findUnique({ where: { id: userId } });
    },
  );

  async getUser(userId: string) {
    return this.tracedFetchUser(userId);
  }
}

Bootstrap

main.ts

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(3000);
}

bootstrap();

What Gets Traced

With autoInstrumentations: ['http', 'nestjs-core']:

• HTTP server spans — automatic per-request spans
• NestJS controllers/services — handler execution time
• Guards, interceptors, pipes — lifecycle timing
• Your trace() calls — business logic spans as children

Examples

• example-nestjs — NestJS with HTTP/NestJS auto-instrumentation and manual trace() in services.