@eropple/nestjs-bunyan

@eropple/nestjs-bunyan

This package contains a module to provide Bunyan logging across a NestJS application. It supports full request-specific logging by providing a request-scoped Bunyan logger in the dependency injector and includes an in/out interceptor for recording request data and request timing.

Installation

yarn add @eropple/nestjs-bunyan or npm install --save @eropple/nestjs-bunyan depending on your package manager of choice.

Usage

@eropple/nestjs-bunyan expects you to define a Bunyan logger somewhere in your application--a global, a logger via ConfigService, whatever makes the most sense for your application.

Import it at the root of your application:

import { Module } from '@nestjs/common';
import { LoggingModule } from "@eropple/nestjs-bunyan";

import { ROOT_LOGGER } from './logger';
import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  imports: [
    LoggingModule.forRoot(ROOT_LOGGER, {})
  ],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}

This will do a few things:

• It adds the root logger to the DI container. You can get it with the @RootLogger() decorator on your constructor parameter. (You can use this with Scope.DEFAULT injected services.)
• It adds the request logger to the DI container. This logger includes the request's correlation ID with every log entry. You can get it with the @Logger() decorator on your constructor parameter. You must only use this with Scope.REQUEST injected services (and NestJS should transitively make anything that depends on @Logger() a request-scoped provider automatically.)

Important note: this module expects a request to have some kind of correlation ID. By default, this will be X-Correlation-Id (and if you need to inject that, might I recommend @eropple/nestjs-correlation-id?), but you can change it to, for example, X-Request-Id, by passing something like correlationIdHeader: "X-Request-Id" to the options in LoggingModule.forRoot().

Request Tracking

@eropple/nestjs-bunyan also includes a request tracking middleware that records into the log the start and end of every request coming into your server. The start log entry includes all request headers; the end log entry includes the time taken with the request and the status code. You can use these, plus the correlation ID, to determine overall request timings.

The implementation is currently a little tortured (to write, not to use), so it's implemented a little differently than normal. Use it a-like so:

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.use(CorrelationIdMiddleware());
  LoggingModule.addRequestMiddleware(app);

  await app.listen(3000);
}
bootstrap();

The request middleware records timing in milliseconds, so it probably doesn't matter too much where in your middleware chain you do it, but it's probably best to put it as early in the process as possible, immediately behind whatever middleware is ensuring that you have a working correlation ID.

Controller Example

import * as Bunyan from "bunyan";
import { Controller, Get, Scope } from '@nestjs/common';
import { Logger } from "@eropple/nestjs-bunyan";

import { AppService } from './app.service';

@Controller({ scope: Scope.REQUEST })
export class AppController {
  private readonly _logger: Bunyan;

  constructor(
    @Logger() requestLogger: Bunyan,
    private readonly appService: AppService
  ) {
    this._logger = requestLogger.child({ component: this.constructor.name });
  }

  @Get()
  getHello(): Promise<string> {
    return new Promise((resolve, reject) => {
      this._logger.info("getHello hit; pausing.");

      setTimeout(() => {
        this._logger.info('getHello done!');
        resolve(this.appService.getHello());
      }, 1000)
    })
  }
}

And some sample output, when passed through the bunyan executable:

[2019-05-29T01:58:11.789Z]  INFO: example-app/RequestTracker/27937 on bigboss:  (correlationId=7f8901a5-8706-4059-875a-fb69a28a4213, request=start, method=GET, url=/, ip=::1)
    headers: {
      "host": "localhost:3000",
      "user-agent": "curl/7.61.1",
      "accept": "*/*",
      "x-correlation-id": "7f8901a5-8706-4059-875a-fb69a28a4213"
    }
[2019-05-29T01:58:11.796Z]  INFO: example-app/AppController/27937 on bigboss: getHello hit; pausing. (correlationId=7f8901a5-8706-4059-875a-fb69a28a4213)
[2019-05-29T01:58:12.799Z]  INFO: example-app/AppController/27937 on bigboss: getHello done! (correlationId=7f8901a5-8706-4059-875a-fb69a28a4213)
[2019-05-29T01:58:12.802Z]  INFO: example-app/RequestTracker/27937 on bigboss:  (correlationId=7f8901a5-8706-4059-875a-fb69a28a4213, request=end, code=200, ms=1013)