Bunyan Logger Service

NestJS LoggerService that uses Bunyan.

Installation

npm i @nest-toolbox/bunyan-logger

Example

You can pass any custom stream supported by Bunyan

import { NestFactory } from '@nestjs/core';
import { BunyanLoggerService } from "@nest-toolbox/bunyan-logger";
import { AppModule } from './app.module';
const Elasticsearch = require('bunyan-elasticsearch');

async function bootstrap() {
  const app = await NestFactory.create<NestExpressApplication>(
    ApplicationModule,
    {
      logger: new BunyanLoggerService({
        projectId: 'project',
        formatterOptions: {
          outputMode: 'long',
        },
      }),
    },
  );

  const esStream = new Elasticsearch({
    type: 'logs',
    host: 'localhost:9300',
  });

  const app = await NestFactory.create<NestExpressApplication>(
    ApplicationModule,
    {
      logger: new BunyanLoggerService({
        projectId: 'project',
        formatterOptions: {
          outputMode: 'long',
        },
        extraFields?: {
          environment:'production',
          microservice: 'users',
        };
        customStreams: [
          { stream: esStream },
          {
            path: 'foo.log',
          },
        ],
      }),
    },
  );

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

BunyanLoggerService constructor options

check https://github.com/thlorenz/bunyan-format

options: {
    projectId: string;
    formatterOptions: {
      outputMode: string;
      color?: boolean;
      levelInString?: boolean;
      colorFromLevel?: any;
      src?: boolean;
    };
    customStreams?: Bunyan.Stream[];
    extraFields?: {
      [key: string]: string;
    };
    maxLength?: number; // Optional: Maximum length for log messages. Messages exceeding this length will be truncated.
}

Options

• projectId (required): The project identifier used as the logger name
• formatterOptions (required): Configuration for bunyan-format. See bunyan-format documentation for details
  • outputMode: Output format (short, long, simple, json, bunyan)
  • color: Enable/disable colors in output (default: true if not specified)
  • levelInString: Display log level as string
  • colorFromLevel: Custom color mapping for log levels
  • src: Include source file information
• customStreams (optional): Additional Bunyan streams (e.g., file streams, Elasticsearch streams)
• extraFields (optional): Additional fields to include in all log entries
• maxLength (optional): Maximum character length for log messages. Messages longer than this value will be truncated. Useful for limiting log size in production environments.

Example with maxLength

import { NestFactory } from '@nestjs/core';
import { BunyanLoggerService } from "@nest-toolbox/bunyan-logger";
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule, {
    logger: new BunyanLoggerService({
      projectId: 'MyApp',
      formatterOptions: {
        outputMode: 'short',
        color: true,
      },
      maxLength: 100, // Limit log messages to 100 characters
    }),
  });

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