@algoan/nestjs-logging-interceptor

A Nest interceptor to log the incoming/outgoing requests.

NestJS Logging interceptor

A simple NestJS interceptor catching request details and logging it using the built-in Logger class. It will use the default Logger implementation unless you pass your own to your Nest application.

Installation

npm install --save @algoan/nestjs-logging-interceptor

Usage

Default usage

Use the interceptor as a global interceptor (cf. refer to the last paragraph of this section for more details).

Example:

import { Module } from '@nestjs/common';
import { APP_INTERCEPTOR } from '@nestjs/core';
import { LoggingInterceptor } from '@algoan/nestjs-logging-interceptor';

/**
 * Core module: This module sets the logging interceptor as a global interceptor
 */
@Module({
  providers: [
    {
      provide: APP_INTERCEPTOR,
      useClass: LoggingInterceptor,
    },
  ],
})
export class CoreModule {}

In the example above, the interceptor is provided by the CoreModule. It could be set on any module that your main module is using.

Factory

You can also manually pass an interceptor instance through a factory function. This will give the possibility to set a userPrefix on the head of the default context message:

Example:

import { Module } from '@nestjs/common';
import { APP_INTERCEPTOR } from '@nestjs/core';
import { LoggingInterceptor } from '@algoan/nestjs-logging-interceptor';

/**
 * Core module: This module sets the logging interceptor as a global interceptor
 */
@Module({
  providers: [
    {
      provide: APP_INTERCEPTOR,
      useClass: () => {
        const interceptor: LoggingInterceptor = new LoggingInterceptor();
        interceptor.setUserPrefix('ExampleApp');

        return interceptor;
      },
    },
  ],
})
export class CoreModule {}

The context message will be preprend by the provided userPrefix:

[LoggingInterceptor - GET - /error] Incoming request - GET - /error
==>
[ExampleApp - LoggingInterceptor - GET - /error] Incoming request - GET - /error

Log messages

This interceptor logs:

• incoming request details

Default Logger messages

# Incoming request details

# info level
[Nest] 27080   - 04/06/2020, 10:11:54 AM   [LoggingInterceptor - GET - /] Object:
{
  "message": "LoggingInterceptor - GET - /",
  "method": "GET",
  "body": {},
  "headers": {
    "host": "localhost:3000",
    "user-agent": "insomnia/7.1.1",
    "authorization": "Bearer 1234",
    "accept": "*/*"
  }
}

• outgoing request details (info + (debug | warn | error))

# Success example

# Info level
[Nest] 27080   - 04/06/2020, 10:11:54 AM   [LoggingInterceptor - 200 - GET - /] Object:
{
  "message": "LoggingInterceptor - 200 - GET - /",
  "body": "Hello World!"
}

# Warning example

# warn level
[Nest] 27080   - 04/06/2020, 10:12:44 AM   [LoggingInterceptor - 400 - GET - /badrequest] Object:
{
  "method": "GET",
  "url": "/badrequest",
  "error": {
    "response": {
      "statusCode": 400,
      "message": "Bad Request"
    },
    "status": 400,
    "message": "Bad Request"
  },
  "body": {},
  "message": "LoggingInterceptor - 400 - GET - /badrequest"
}

# Error example

# error level
[Nest] 27080   - 04/06/2020, 10:12:17 AM   [LoggingInterceptor - 500 - GET - /error] Object:
{
  "method": "GET",
  "url": "/error",
  "body": {},
  "message": "LoggingInterceptor - 500 - GET - /error"
}
 +2ms
Error: Internal Server Error
    at AppController.error (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/dist/app.controller.js:25:15)
    at /Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/@nestjs/core/router/router-execution-context.js:37:29
    at InterceptorsConsumer.transformDeffered (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/@nestjs/core/interceptors/interceptors-consumer.js:30:28)
    at /Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/@nestjs/core/interceptors/interceptors-consumer.js:14:48
    at Observable._subscribe (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/rxjs/internal/observable/defer.js:10:21)
    at Observable._trySubscribe (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/rxjs/internal/Observable.js:44:25)
    at Observable.subscribe (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/rxjs/internal/Observable.js:30:22)
    at Object.subscribeToResult (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/rxjs/internal/util/subscribeToResult.js:12:23)
    at MergeMapSubscriber._innerSub (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/rxjs/internal/operators/mergeMap.js:82:53)
    at MergeMapSubscriber._tryNext (/Users/philippediep/Documents/workspace/algoan/examples/example-manager/node_modules/rxjs/internal/operators/mergeMap.js:76:14)

Use a custom Logger

Nest-pino

In this example, we are going to override the default Logger implementation with a Pino logger (refer to the this official NestJS documentation)

import { Module } from '@nestjs/common';
import { CoreModule } from './core/core.module'; // the module importing the @algoan/nestjs-logging-interceptor
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { LoggerModule } from 'nestjs-pino';

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

Then in the application bootstrap, set the Pino logger as the one to substitute to the default Logger.

import { NestFactory} from '@nestjs/core';
import { Logger } from "nestjs-pino";
import { MainModule } from './main.module';

async function bootstrap() {
  const app = await NestFactory.create(MainModule,{
    logger: false
  });

  app.useLogger(app.get(Logger))
  await app.listen(3000);
}
bootstrap();

The Pino logger will be set as the Logger implementation to use.

# With default Logger
[Nest] 84392   - 04/03/2020, 2:02:04 PM   [RoutesResolver] AppController {}: +7ms
[Nest] 84392   - 04/03/2020, 2:02:04 PM   [RouterExplorer] Mapped {, GET} route +3ms
[Nest] 84392   - 04/03/2020, 2:02:04 PM   [RouterExplorer] Mapped {/badrequest, GET} route +0ms
[Nest] 84392   - 04/03/2020, 2:02:04 PM   [RouterExplorer] Mapped {/error, GET} route +0ms
[Nest] 84392   - 04/03/2020, 2:02:04 PM   [NestApplication] Nest application successfully started +3ms

# With Pino Logger
{"level":30,"time":1585915251917,"pid":83826,"hostname":"computername.local","context":"RoutesResolver","msg":"AppController {}: true","v":1}
{"level":30,"time":1585915251919,"pid":83826,"hostname":"computername.local","context":"RouterExplorer","msg":"Mapped {, GET} route true","v":1}
{"level":30,"time":1585915251919,"pid":83826,"hostname":"computername.local","context":"RouterExplorer","msg":"Mapped {/badrequest, GET} route true","v":1}
{"level":30,"time":1585915251919,"pid":83826,"hostname":"computername.local","context":"RouterExplorer","msg":"Mapped {/error, GET} route true","v":1}
{"level":30,"time":1585915251921,"pid":83826,"hostname":"computername.local","context":"NestApplication","msg":"Nest application successfully started true","v":1}