NestJS　Winstonでのログ出力(アクセスログ)

NestJSプロジェクト作成

npm i -g @nestjs/cli
nest new "プロジェクト名"

Winstonインストール

yarn add winston
yarn add winston-daily-rotate-file # rotation用

カスタムLoggerのモジュール作成

nest g mo customLogger

アクセスログのservice作成

custom-logger/access-logger.service.ts

import { Injectable, LoggerService } from '@nestjs/common';
import { createLogger, format, Logger } from 'winston';
import * as DailyRotateFile from 'winston-daily-rotate-file';
import * as Transport from 'winston-transport';

@Injectable()
export class AccessLoggerService implements LoggerService {
  logger: Logger;

  constructor() {
    /** ローテーション */
    const logTransFormStream = new DailyRotateFile({
      level: 'info',
      dirname: `log/access/`,
      filename: `log_%DATE%.log`,
      datePattern: 'YYYY-MM-DD',
      zippedArchive: true,
      maxFiles: '1d',
    });

    // ログローテンションするタイミングのイベント
    // eslint-disable-next-line @typescript-eslint/no-empty-function
    logTransFormStream.on('rotate', () => {});

    const t: Transport[] = [logTransFormStream];

    this.logger = createLogger({
      format: format.combine(format.timestamp(), format.json()),
      transports: t,
    });
  }

  log(message: string) {
    this.logger.info(message);
  }
  error(message: string) {
    this.logger.error(message);
  }
  warn(message: string) {
    this.logger.warn(message);
  }

  debug(message: string) {
    this.logger.debug(message);
  }
}

※rotateのオプション関連は下記url参照
https://github.com/winstonjs/winston-daily-rotate-file

###　ログ出力の確認

custom-logger/custom-logger.module.ts

import { Module } from '@nestjs/common';
import { AccessLoggerService } from './access-logger.service';

@Module({
  providers: [AccessLoggerService],
  exports: [AccessLoggerService],
})
export class CustomLoggerModule {}

app.service.ts

import { Injectable } from '@nestjs/common';
import { AccessLoggerService } from './custom-logger/access-logger.service';

@Injectable()
export class AppService {
  constructor(private readonly accessLogger: AccessLoggerService) {}
  getHello(): string {
    this.accessLogger.log('test');
    return 'Hello World!';
  }
}

yarn start:dev

http:localhost:3000にアクセス

ログ確認

アクセス時に自動でlogを出力するように修正 ※inspectorを使用

interceptors/logging.inspector.ts

import {
  CallHandler,
  ExecutionContext,
  Injectable,
  NestInterceptor,
} from '@nestjs/common';
import { Request } from 'express';
import { catchError, Observable, throwError } from 'rxjs';
import { AccessLoggerService } from 'src/custom-logger/access-logger.service';

@Injectable()
export class LoggingInterceptor implements NestInterceptor {
  constructor(private readonly accessLogger: AccessLoggerService) {}
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const request = context.switchToHttp().getRequest<Request>();
    const requestData = {
      ip: request.ip,
      method: request.method,
      url: request.url,
      body: request.body || {},
    };

    this.accessLogger.log(JSON.stringify(requestData));

    return next.handle().pipe(
      catchError((err) => {
        // Exceptionのログを出力したい場合はここで実装
        // this.errorLogger.error({
        //   ...requestData,
        //   status: err?.status ?? err?.statusCode ?? 500,
        //   message: err?.message ?? '',
        // });
        return throwError(() => new Error(err));
      }),
    );
    // .pipe(tap(() => console.log(`After... ${Date.now() - now}ms`)));
  }
}

app.module.ts

import { Module } from '@nestjs/common';
import { APP_INTERCEPTOR } from '@nestjs/core';
import { AppController } from './app.controller';
import { AppService } from './app.service';
import { CustomLoggerModule } from './custom-logger/custom-logger.module';
import { LoggingInterceptor } from './interceptors/logging.inspector';

@Module({
  imports: [CustomLoggerModule],
  controllers: [AppController],
  providers: [
    AppService,
    { provide: APP_INTERCEPTOR, useClass: LoggingInterceptor },
  ],
})
export class AppModule {}

テストで追加したログを削除する

app.service.ts

import { Injectable } from '@nestjs/common';

@Injectable()
export class AppService {
  getHello(): string {
    return 'Hello World!';
  }
}

再度アクセスする

ログ確認