Winston File transport logs escape characters

Question

I am using winston to log in a Sails app. This is my configuration:

var customLogger = new winston.Logger({
    transports: [
        new(winston.transports.File)({
            level: 'debug',
            filename: 'app.log',
            colorize: false,
            showLevel: false,
            prettyPrint: false,
            exitOnError: false,
            json: true,
            zippedArchive: true,
            maxsize: 1000000000,
            maxFiles: 30,
            tailable: true
        }),
        new(winston.transports.Console)({
            level: 'info',
            exitOnError: false,
            colorize: false,
            showLevel: false
        })
    ],
});

But in the output file there are odd characters.

{"level":"info","message":"\u001b[32minfo: \u001b[39m","timestamp":"2016-05-12T17:58:03.281Z"}

Answer 1

I did face a similar issue and resolved it by removing winston.format.colorize() statement from the below code to get rid of the odd or escape codes as part of the log file.

const logFormat = winston.format.combine (
winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss.SSS' }),
winston.format.colorize(),
winston.format.align(),
winston.format.printf(
    info => `${info.timestamp} ${info.level.toUpperCase()}: ${info.message}`    
));

While below shared is the complete working code without any issues associated with odd or escape codes.

Default configurations captured as part of /zipCode/config/default.json file

{
   "port":      3000,
   "logConfig": {
        "logFolder":    ".//logs//",
        "logFile":      "zip-code-%DATE%.log",
        "logLevel":     "info"
    }
}

Incorporating the create logger implementation as part of /zipCode/logger/log.js file

/**
 * @author: dinesh.lomte
 */
const winston = require('winston');
const dailyRotateFile = require('winston-daily-rotate-file');
const config = require('config');
const logFormat = winston.format.combine (
    winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss.SSS' }),
    winston.format.align(),
    winston.format.printf(
        info => `${info.timestamp} ${info.level.toUpperCase()}: ${info.message}`    
    )
);
const transport = new dailyRotateFile({
    filename:       config.get('logConfig.logFolder') + config.get('logConfig.logFile'),
    datePattern:    'YYYY-MM-DD',
    zippedArchive:  true,
    maxSize:        '20m',
    maxFiles:       '14d',
    level:          config.get('logConfig.logLevel')        
});

transport.on('rotate', function(oldFile, newFile) {
    // Call function like upload to s3 or on cloud
});

const logger = winston.createLogger({
    format:     logFormat,
    transports: [
        transport,
        new winston.transports.Console({
            level:  config.get('logConfig.logLevel')
        })
    ]
});

module.exports = logger;

Below /zipCode/api/controller.js file showing the logger usage

/**
 * @author: dinesh.lomte
 */
'use strict';

var distance = require('../service/distance');
var logger = require('../logger/log');

var controllers = {
    get_distance: function(req, res) {
        logger.info('Processing get_distance request...');
        distance.find(req, res, function(err, dist) {
            if (err) {
                logger.error('Failed to process distance request, due to: ' + err);
                res.send(err);
            }
            logger.debug('Processed get_distance request...');
            res.json(dist);
        });
    }
};

module.exports = controllers;