Winston: How to customize timestamp format?

you can read the source code to help yourself customize the format. i can give you an example of mine.

const winston = require('winston');
const moment = require('moment');
const util = require('util');
const MESSAGE = Symbol.for('message');

const logger = winston.createLogger({
    level: 'info',
    format: winston.format.combine(
        winston.format(function(info, opts) {
            prefix = util.format('[%s] [%s]', moment().format('YYYY-MM-DD hh:mm:ss').trim(), info.level.toUpperCase());
            if (info.splat) {
                info.message = util.format('%s %s', prefix, util.format(info.message, ...info.splat));
            } else {
                info.message = util.format('%s %s', prefix, info.message);
            }
            return info;
        })(),
        winston.format(function(info) {
            info[MESSAGE] = info.message + ' ' + JSON.stringify(
                Object.assign({}, info, {
                    level: undefined,
                    message: undefined,
                    splat: undefined
                })
            );
            return info;
        })()
    ),
    transports: [
        new winston.transports.Console(),
        new winston.transports.File({ filename: './logs/bitcoin.log' })
    ]
});

This is so extremly complicated for the simplest requirement of just printing a timestamp (which should be default anyway) :/

Here's what I do...

//logger.js

const winston = require('winston');
const moment = require('moment');

// create formatter for dates used as timestamps
//const tsFormat = () => (new Date()).toLocaleTimeString();
const tsFormat = () => moment().format('YYYY-MM-DD hh:mm:ss').trim();

// define a logger with 2 transports - console and a file
const logger = new (winston.Logger)({
  transports: [
    // colorize the output to the console
    new (winston.transports.Console)({
        timestamp: tsFormat,
        colorize: true
    }),
    new winston.transports.File({
        filename: './logs/ttracker.log',
        timestamp: tsFormat,            // makes timestamp 'pretty'
        json: false                 // makes log format just like console output
    })
  ]
});

// set logging level one of { error: 0, warn: 1, info: 2, verbose: 3, debug: 4, silly: 5 }
logger.level = 'debug';

module.exports = logger;

P.S. I only set timestamp: to a function because I don't like the default format which you get by setting timestamp: true, i.e. 2017-12-05T08:22:09.179Z

@jimwhurr - for me, your code (node v6.11.0) produces:

Error: winston.Logger was moved in [email protected].
Use a winston.createLogger instead.
    at new <anonymous> (/Users/adrian/Documents/winston_test/node_modules/winston/lib/winston/common.js:162:15)
    at Object.<anonymous> (/Users/adrian/Documents/winston_test/index.js:7:16)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.runMain (module.js:604:10)
    at run (bootstrap_node.js:389:7)
    at startup (bootstrap_node.js:149:9)

Taking the examples here, I created a simpler standalone example:

https://gist.github.com/a-h/d02bd4ff238e5923fcf5369233e51401

const winston = require('winston');
const MESSAGE = Symbol.for('message');

const jsonFormatter = (logEntry) => {
  const base = { timestamp: new Date() };
  const json = Object.assign(base, logEntry)
  logEntry[MESSAGE] = JSON.stringify(json);
  return logEntry;
}

const logger = winston.createLogger({
  level: 'info',
  format: winston.format(jsonFormatter)(),
  transports: new winston.transports.Console(),
});

logger.info('message content', { "context": "index.js", "metric": 1 })
logger.info('message content 2')

Output:

{"timestamp":"2017-12-07T16:07:10.518Z","context":"index.js","metric":1,"level":"info","message":"message content"}
{"timestamp":"2017-12-07T16:07:10.520Z","message":"message content 2","level":"info"}

Hi, here is another option for logging with timestamp (tested on 3.0.0-rc0):

const winston = require('winston');
var customFormat = winston.format.combine(
winston.format(
function dynamicContent(info, opts) {
info.level = 'info';
if(info.time) {
var dt = new Date(),
date_now = dt.getDate() < 10 ? '0'+ dt.getDate() : dt.getDate(),
month_now = (dt.getMonth() + 1) < 10 ? '0'+ (dt.getMonth() + 1) : (dt.getMonth() + 1),
year_now = dt.getFullYear(),
hrs_now = dt.getHours(),
mins_now = dt.getMinutes(),
secs_now = dt.getSeconds(),
millisec_now = dt.getMilliseconds();
info.time = ' '+date_now+'-'+month_now+'-'+year_now+' '+hrs_now+':'+mins_now+':'+secs_now+':'+millisec_now+' ';
}
return info;
}
)(),
winston.format.simple() //format output, also posible use: .json() (instead of .simple)
);

const logger = winston.createLogger({
level: 'info',
format: customFormat,
transports: [
new winston.transports.File({ filename: 'logs.log' })
]
});
module.exports = logger;`

And for log:

logger.log({ time: true, level: 'info', message: 'message for logging' });

May be it will be helpful.

you can customize the timestamp with a format string:

winston.createLogger({
    level: ...
    format: winston.format.combine(
        winston.format.label({ label: '[my-label]' }),
        winston.format.timestamp({
            format: 'YYYY-MM-DD HH:mm:ss'
        }),
        winston.format.simple()
    ),
    transports: ...
});

winston.createLogger({
    level: ...
    format: winston.format.combine(
        winston.format.label({ label: '[my-label]' }),
        winston.format.timestamp({
            format: 'YYYY-MM-DD HH:mm:ss'
        }),
        winston.format.simple()
    ),
    transports: ...
});

This should be on the docs. @felipemullen Thank you!

@felipemullen thanks for providing that sample. Agree with @ricardoaat this should be in the docs, so ... now it is: examples/custom-timestamp.js

@youngkylejan oh oh.....That's good help...
But I've a problem...what's {} in end of log?

[2018-05-14 04:39:52] [INFO] API running on localhost:3000 {}

I'm new to Winston and, gotta say, the docs are surprisingly hard to follow :(

Somehow, I ended up with the following apparently simpler solution:

winston.createLogger({
    level: ...
    format: winston.format.printf(info => `${new Date().toISOString()} ${info.message}`),
    transports: ...
});

@hosseinGanjyar
Change
info[MESSAGE] = info.message + ' ' + JSON.stringify(...);
to just
info[MESSAGE] = info.message;

This worked for me.

Setup:

• JSON logs
• Timestamps
• Log rotation
• File and console logging

import winston from 'winston';
import DailyRotateFile from 'winston-daily-rotate-file';
import fs from 'fs';
import path from 'path';

const LOG_DIR = path.normalize(`${process.cwd()}/logs`);

if (!fs.existsSync(LOG_DIR)) {
  fs.mkdirSync(LOG_DIR);
}

const logger = winston.createLogger({
  exitOnError: false,
  silent: process.env.SUPPRESS_LOGS,
  level: process.env.LOG_LEVEL || 'info',
  format: winston.format.combine(
    winston.format.timestamp({
      format: 'YYYY-MM-DD HH:mm:ss',
    }),
    winston.format.json(),
  ),
  transports: [
    new winston.transports.Console(),
    new DailyRotateFile({
      dirname: LOG_DIR,
      filename: '%DATE%.log',
      datePattern: 'YYYY-MM-DD-HH',
      zippedArchive: false,
      maxSize: '1m',
      maxFiles: '14d',
    }),
  ],
});

export default logger;

This is all for winston 3.0.0 and @types/winston 2.3.9

const consoleFormat = winston.format.printf(info => {
    const d = new Date();
    const timestamp = d.toLocaleTimeString();
    return `${timestamp} ${info.level}: ${info.message}`;

this returns a timestamp that is just the time in the current timezone.
for fileFormat I use

const timestamp = `${d.toISOString()} (${d.toLocalTimeString()})`;

then

const logger = winston.createLogger({
    level: "debug",
    format: fileFormat,
    transports: [ new winston.transports.File({ filename: "yourname.log", level: "debug"}) ]
});

probably doesn't need level twice. but that's what I'm using currently.

you can customize the timestamp with a format string:

winston.createLogger({
    level: ...
    format: winston.format.combine(
        winston.format.label({ label: '[my-label]' }),
        winston.format.timestamp({
            format: 'YYYY-MM-DD HH:mm:ss'
        }),
        winston.format.simple()
    ),
    transports: ...
});

Life saver. Many thanks!!!

For those who are here to find out how to customize format string besides YYYY-MM-DD HH:mm:ss: winston uses fecha under the hood, so you can refer to fecha documentation.

All those examples remove rest parameters in logs. If you want to use format.simple() and only add timestamp to the beginning and remove from rest, this might works for you:

const simpleFormat = format.simple()
const MESSAGE = Symbol.for('message')
const simpleTimestamp = format(info => {
  const { timestamp, ...rest } = info
  const simpled = simpleFormat.transform(rest)
  if (typeof simpled !== 'boolean') {
    // @ts-ignore
    simpled[MESSAGE] = `${timestamp} ${simpled[MESSAGE]}`
  }
  return simpled
})

logger.add(new transports.Console({
  format: format.combine(
      format.timestamp(),
      format.colorize(),
      simpleTimestamp(),
  ),
}))