Logging request/response in Nest.js

I ended up injecting a classic logger on the raw app. This solution is not the best since it is not integrated to the Nest flow but works well for standard logging needs.

import { NestFactory } from '@nestjs/core';
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify';
import { ApplicationModule } from './app.module';
import * as morgan from 'morgan';

async function bootstrap() {
    const app = await NestFactory.create<NestFastifyApplication>(ApplicationModule, new FastifyAdapter());
    app.use(morgan('tiny'));

    await app.listen(process.env.PORT, '0.0.0.0');
}

if (isNaN(parseInt(process.env.PORT))) {
    console.error('No port provided. 👏');
    process.exit(666);
}

bootstrap().then(() => console.log('Service listening 👍: ', process.env.PORT));

How about use finish event instead of close event.

import { Request, Response, NextFunction } from "express";
import { Injectable, NestMiddleware, Logger } from "@nestjs/common";

@Injectable()
export class LoggerMiddleware implements NestMiddleware {
  private logger = new Logger("HTTP");

  use(request: Request, response: Response, next: NextFunction): void {
    const { ip, method, originalUrl } = request;
    const userAgent = request.get("user-agent") || "";

    response.on("finish", () => {
      const { statusCode } = response;
      const contentLength = response.get("content-length");

      this.logger.log(
        `${method} ${originalUrl} ${statusCode} ${contentLength} - ${userAgent} ${ip}`,
      );
    });

    next();
  }
}

Because as far as know express connection is maintained after send response.
So close event can't be fired

Reference

01. Node document about response event.
02. Github issue

I decided to use Morgan as middleware to intercept the requests since I like the formatting options, whilst using the standard Nest Logger to handle the output to retain consistency with the rest of my app.

// middleware/request-logging.ts
import { Logger } from '@nestjs/common';
import morgan, { format } from 'morgan';

export function useRequestLogging(app) {
    const logger = new Logger('Request');
    app.use(
        morgan('tiny', {
            stream: {
                write: (message) => logger.log(message.replace('\n', '')),
            },
        }),
    );
}

// main.ts
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { useRequestLogging } from './middleware/request-logging';

async function bootstrap() {
    const app = await NestFactory.create(AppModule);
    useRequestLogging(app);
    await app.listen(configService.get<number>('SERVER_PORT'));
    logger.log(`Application is running on: ${await app.getUrl()}`);
}

https://github.com/julien-sarazin/nest-playground/issues/1#issuecomment-682588094

You can use middleware for that.

import { Injectable, NestMiddleware, Logger } from '@nestjs/common';

import { Request, Response, NextFunction } from 'express';

@Injectable()
export class AppLoggerMiddleware implements NestMiddleware {
  private logger = new Logger('HTTP');

  use(request: Request, response: Response, next: NextFunction): void {
    const { ip, method, path: url } = request;
    const userAgent = request.get('user-agent') || '';

    response.on('close', () => {
      const { statusCode } = response;
      const contentLength = response.get('content-length');

      this.logger.log(
        `${method} ${url} ${statusCode} ${contentLength} - ${userAgent} ${ip}`
      );
    });

    next();
  }
}

and in the AppModule

export class AppModule implements NestModule {
  configure(consumer: MiddlewareConsumer): void {
    consumer.apply(AppLoggerMiddleware).forRoutes('*');
  }
}