NodeJS Request Log Tracing : Logger

logger.js

const { createLogger, transports, format } = require('winston');
const {combine, printf} = format;
const requestTracing = require('request-tracing'); // Wrapper library to read the tracing information from CLS context

const loggerFormat = printf((info) => {
  const tracingId = requestTracing.getTracingId(); // Same as requestTracingNamespace.get(tracingIdContextKeyName);
  let formatObject = `${info.level || '-'} ${info.timestamp || '-'} ${tracingId || '-'} ${info.message}`;
  // ...
  return formatObject;
});

const logger = createLogger({
  transports: [
    new transports.Console({
      level: process.env.LOG_LEVEL,
      format: combine(
        // ...
        loggerFormat
      )
    })
  ]
});