NestJS：如何为不同环境设置全局日志级别

Question

I am using the NestJS in-built logger. I couldn't find an option to set the global log level. For eg log level as 'verbose' for dev environment and log level as 'error' for prod environment.

Also, is there an option to disable the stuff that NestJS adds in the output ie timestamp and other info and only log the message? I need this as we use Kibana logs and it automatically adds the required fields.

Answer 1

You can set up log levels in your main.ts file:

const app = await NestFactory.create(AppModule, {
  logger: process.env.NODE_ENV === 'development' ? ['log', 'debug', 'error', 'verbose', 'warn'] : ['error', 'warn'],
});

Answer 2

You can write your own Logger with that logic and use it as a service or you can set it globally

export class MyLogger extends Logger {
  error(message: string, trace: string) {
    // add your tailored logic here
    super.error(message, trace);
  }
}

---

const app = await NestFactory.create(ApplicationModule, {
  logger: new MyLogger(),
});

Answer 3

I looked for a log level switcher me too, but I didn't found.

As proposed in the previous comment, you can create a custom logger and apply it globally to ApplicationModule .

This custom logger will be invoked either by Nest and by you in your controller/service/etc.

            NestJs
                    \
                      use -> CustomLogger 
                    /
Your business logic

In your CustomLogger call either super.logger (nestjs built-in logger) and also the winston logger .

Winston Logger can be set up with transporter for kibana and accept a log level.

const winstonLogger = new winston.Logger({
                 level: LOG_LEVEL,
                 transports: [
                    <here enable trasport for logstash/kibana>
                  }),
                ],
                ...
               });

export class CustomLogger extends Logger {

  debug(message: string) {
    super.error(message, trace);
    winstonLogger.error(message)
  }

  ... (the same for warn, error, etc)
}

Finally register the CustomLogger

 const app = await NestFactory.create(ApplicationModule, {
  logger: new CustomLogger(),
 });