How can I add timestamp to logs using Node.js library Winston?

Question

I want to add timestamp to logs. What is the best way to achieve this?

Answer 1

Although I'm not aware of winston, this is a suggestion. I use log4js for logging & my logs by default look like this

[2012-04-23 16:36:02.965] [INFO] Development - Node Application is running on port 8090
[2012-04-23 16:36:02.966] [FATAL] Development - Connection Terminated to  '127.0.0.1' '6379'

Development is the environment of my node process & [INFO|FATAL] is log level

Maintaining different profiles for logging is possible in log4js. I have Development & Production profiles. Also there are logger types like rolling file appender, console appender, etc. As a addon your log files will be colorful based on the log level [Trace, Info, Debug, Error, Fatal] ;)

log4js will override your console.log It is a configurable parameter now in 0.5+

Answer 2

I was dealing with the same issue myself. There are two ways I was able to do this.

When you include Winston, it usually defaults to adding a Console transport. In order to get timestamps to work in this default case, I needed to either:

1. Remove the console transport and add again with the timestamp option.
2. Create your own Logger object with the timestamp option set to true.

The first:

var winston = require('winston');
winston.remove(winston.transports.Console);
winston.add(winston.transports.Console, {'timestamp':true});

The second, and cleaner option:

var winston = require('winston');
var logger = new (winston.Logger)({
    transports: [
      new (winston.transports.Console)({'timestamp':true})
    ]
});

Some of the other options for Console transport can be found here:

• level: Level of messages that this transport should log (default 'debug').
• silent: Boolean flag indicating whether to suppress output (default false).
• colorize: Boolean flag indicating if we should colorize output (default false).
• timestamp: Boolean flag indicating if we should prepend output with timestamps (default false). If function is specified, its return value will be used instead of timestamps.

Answer 3

You can use built-in util and forever to achieve logging with timestap for your nodejs server. When you start a server add log output as part of the parameter:

forever start -ao log/out.log server.js

And then you can write util in your server.js

server.js

var util = require('util');
util.log("something with timestamp");

The output will look something like this to out.log file:

out.log

15 Mar 15:09:28 - something with timestamp

Answer 4

I took Biswadev's answer and created a stringified JSON object. This way if i need to process the logs later it will be in a well structured format.

const winston = require('winston');
const { createLogger, format, transports } = require('winston');

const dotenv = require('dotenv');
dotenv.config();

var logger = createLogger({
    level: 'info',
    format: format.combine(
        format.timestamp({
            format: 'YYYY-MM-DD HH:mm:ss',
        }),
        format.printf((info) =>
            JSON.stringify({
                t: info.timestamp,
                l: info.level,
                m: info.message,
                s: info.splat !== undefined ? `${info.splat}` : '',
            }) + ','
        )
    ),
});

if (process.env.NODE_ENV !== 'PRODUCTION') {
    logger.add(new transports.Console({ format: winston.format.cli() }));

    // Turn these on to create logs as if it were production
    // logger.add(new transports.File({ filename: 'log/output/error.log', level: 'error' }));
    // logger.add(new transports.File({ filename: 'log/output/warn.log', level: 'warn' }));
    // logger.add(new transports.File({ filename: 'log/output/info.log', level: 'info' }));
} else {
    logger.add(new transports.File({ filename: 'log/output/error.log', level: 'error' }));
    logger.add(new transports.File({ filename: 'log/output/warn.log', level: 'warn' }));
    logger.add(new transports.File({ filename: 'log/output/info.log', level: 'info' }));
}

module.exports = {
    logger,
};

Usage:

app.listen(port, () => logger.info(`app is running on port ${port}`));

Output:

info.log file:

{"t":"2020-08-06 08:02:05","l":"info","m":"app is running on port 3001","s":""},

Console:

info:    app is running on port 3001

Answer 5

Sometimes default timestamp format can be not convenient for you. You can override it with your implementation.

Instead of

var winston = require('winston');
var logger = new (winston.Logger)({
transports: [
  new (winston.transports.Console)({'timestamp':true})
]
});

you can write

var winston = require('winston');
var logger = new (winston.Logger)({
transports: [
  new (winston.transports.Console)({
     'timestamp': function() {
        return <write your custom formatted date here>;
     }
  })
]
});

See https://github.com/winstonjs/winston#custom-log-format for the details

Answer 6

we could use console-stamp to add timestamp and log level to the existing console: require('console-stamp')(console, '[yyyy-mm-dd HH:MM:ss.l]')

See https://github.com/starak/node-console-stamp for the details