logger.js

const { createLogger, format, transports } = require('winston');
require('winston-daily-rotate-file');
const fs = require('fs');
const path = require('path');

const env = process.env.NODE_ENV || 'development';
const logDir = 'log';
const datePatternConfiguration = {
  default: 'YYYY-MM-DD',
  everHour: 'YYYY-MM-DD-HH',
  everMinute: 'YYYY-MM-DD-THH-mm',
};
numberOfDaysToKeepLog = 30;
fileSizeToRotate = 1; // in megabyte

// Create the log directory if it does not exist
if (!fs.existsSync(logDir)) {
  fs.mkdirSync(logDir);
}

const dailyRotateFileTransport = new transports.DailyRotateFile({
  filename: `${logDir}/%DATE%-results.log`,
  datePattern: datePatternConfiguration.everHour,
  zippedArchive: true,
  maxSize: `${fileSizeToRotate}m`,
  maxFiles: `${numberOfDaysToKeepLog}d`
});

const logger = createLogger({
  // change level if in dev environment versus production
  level: env === 'development' ? 'verbose' : 'info',
  handleExceptions: true,
  format: format.combine(
    format.label({ label: path.basename(module.parent.filename) }),
    format.timestamp({
      format: 'YYYY-MM-DD HH:mm:ss',
    }),
    format.printf(info => `${info.timestamp}[${info.label}] ${info.level}: ${JSON.stringify(info.message)}`),
  ),
  transports: [
    new transports.Console({
      level: 'info',
      handleExceptions: true,
      format: format.combine(
        format.label({ label: path.basename(module.parent.filename) }),
        format.colorize(),
        format.printf(
          info => `${info.timestamp}[${info.label}] ${info.level}: ${info.message}`,
        ),
      ),
    }),
    dailyRotateFileTransport,
  ],
});

logger.stream = {
  write: (message) => {
    logger.info(message);
  },
};

module.exports = logger;