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Nestjs Logger

A simplified winston logger for your Nestjs applications

Description​

This package provides a NestJS logger wrapper around the Winston logger library. It allows you to easily configure and use Winston logger within your NestJS application

Installation​

To install the package, run

npm install @squareboat/nestjs-logger

OR

yarn add @squareboat/nestjs-logger

Getting Started​

To register LoggerModule with your app, import the module inside AppModule.

Static Registration​

To register the module statically you can do

import { Module } from "@nestjs/common";
import { LoggerModule } from "@squareboat/nestjs-logger";
import winston from "winston";

@Module({
  imports: [
    LoggerModule.register({
      isGlobal: true,
      default: "properties",
      disableConsole: false,
      loggers: {
        properties: {
          level: "error",
          transports: [new winston.transports.Console()],
        },
      },
    }),
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

1. Create logger.ts file​

Use ConfigModule provided by NestJS to load configurations. To learn about ConfigModule, Click here.

import { registerAs } from "@nestjs/config";
import winston from "winston";
import path from "path";
const { combine, timestamp, printf } = winston.format;

const myFormat = printf(({ level, message, timestamp }) => {
  return `${timestamp} ${level}: ${message}`;
});

export default registerAs("logger", () => {
  return {
    default: "payments",
    disableConsole: process.env.APP_ENV == "local" ? false : true,
    loggers: {
      payments: {
        level: "error",
        format: combine(timestamp(), myFormat),
        transports: [
          new winston.transports.File({
            filename: path.join(process.cwd(), "log", "/payments.log"),
            level: "error",
          }),
        ],
      },
    },
  };
});

By setting disbaleConsole to true you can restrict your console logs to be printed in production or other enviroments. Note that you can define multiple transports for the same logger

2. Register Logger Module​

import { Module } from "@nestjs/common";
import { LoggerModule } from "@squareboat/nestjs-logger";

@Module({
  imports: [
    LoggerModule.registerAsync({
      isGlobal: true,
      imports: [ConfigModule],
      useFactory: (config: ConfigService) => config.get("logger"),
      inject: [ConfigService],
    }),
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

Knowing about Transports​

Transports are the mechanisms by which log messages are delivered to their intended destinations, such as the console, files, or remote servers such as CloudWatch.

To read about other transports that you can use refer to Winston docs.

  1. Console transport The Console transport sends log messages to the console.
...
    transports: [new winston.transports.Console()]
...
  1. File transport The File transport writes log messages to a file. It is recommended to create your log files inside the root directory under the 'log' folder.
...
 transports: [
     new winston.transports.File({
        filename: path.join(process.cwd(), 'log', '/payments.log')
    })
 ]
 ...

Usage​

First import Logger from @squareboat/nestjs-logger

import { Logger } from '@squareboat/nestjs-logger';

To use the logger named "payments" in your application and log an "info" level message, you can use the following code:

Logger('payments').info('Payment successful!!');

To know more about other logging levels refer here.

Available Commands​

We have added some useful commands which we think will add value to your workflow.

node cli logger:rotate-log​

You can use this command to create a zip of all .logs file under your root log directory.