messageFormatter doesn't seem to work (since Winston 3.0.0?)

[navFooh]

Hello,

Recently I upgraded to Winston 3.0.0 and decided to add some message formatting as well. I my old setup I never used the messageFormatter property of winston-cloudwatch, but now I felt a need to.

However it seems like the messageFormatter function is never executed. No matter what I change on the logObject or what I return from the function. Even when I do a console.log in the formatter, it never shows up.

I did notice that the whole formatting system of Winston changed quite a bit since 2.x. Maybe this had an impact on this formatter as well? Do you have a working example somewhere?

Best, Thijs

[lazywithclass]

There are a few examples, none about messageFormatter though... but it might also be that I screwed up somewhere during the upgrade to the newer APIs.

I will add an example for this case, check the result, if that's the case provide a fix, and come back to you; thanks for the issue!

[lazywithclass]

I've just tested this after reading the source code and this example works for me:

var winston = require('winston'),
    WinstonCloudWatch = require('../index');

winston.add(new WinstonCloudWatch({
  messageFormatter: function() {
    return 'will always log this text'
  },
  logGroupName: 'testing',
  logStreamName: 'first',
  awsRegion: 'us-east-1'
}));

winston.error('this will be always overwritten');

Could you please check if that's the case also for you?

[navFooh]

Sorry, I didn't have much time to get back to you recently.

I tried your example and that works fine for me too! So I got curious and tried to find why it didn't work in my original case.

Finally I discovered that when specifying the option jsonMessage: true, it never hits the messageFormatter. Maybe this is desired behaviour, since it's already being formatted as JSON. However, Winston 3 does support combining multiple formatters. Anyway, I'll leave it up to you what to do with it from here :) I don't necessarily need the messageFormatter anymore.

Cheers!

[tiborbaksa]

I ran into the same issue, expecting the format option to be used if messageFormatter is not provided. This is not the case, so I ended up implementing messageFormatter to use the formatted message from the info object:

const winston = require('winston');
const WinstonCloudWatch = require('winston-cloudwatch');
const { MESSAGE } = require('triple-beam');

winston.createLogger({
  format: winston.format.json(), // default since winston 3.0.0
  transports: [
    new WinstonCloudWatch({
      jsonMessage: false,
      messageFormatter(info) {
        return info[MESSAGE];
      },
      // ... other options
    })
  ]
);

I think this should be the default behavior from winston 3.0.0.

[Carlovan]

Also I'd like to mention a couple more things:

• the LogObject (now called info object) changed: the msg property has been replaced with message property (as stated here)
• all transports should derive from winston-transport for unified interface: now the format transport option is missing for WinstonCloudwatch

I'd like to say that using the bult-in Winston formats could be done by setting messageFormatter = winston.format.[...]([...]).transform, but it expects an object with the message property and not msg.

Align this interface WinstonJS' would lead to better usage IMO.

Thank you.

EDIT: typo

[lazywithclass]

@Carlovan @tiborbaksa hello and sorry for the delay, I've been quite busy on both work and non-work related issues.

Is this still relevant? From what I remember by using messageFormatter one could address all formatting needs.

Anyway, I have more free time now and could tackle the issues you're experiencing.
I'm not quite sure I understood the issue, would you please sum up the changes you need so I can come up with a PR tho show a possible implementation?

[fewieden]

@lazywithclass what @Carlovan reported is still valid. I just came across it as well.

Winston Format

{
  format: winston.format.printf(({level, message}) => {
    return `${level} - ${message}`;
  })
}

Winston-CloudWatch MessageFormatter

{
  messageFormatter: ({level, msg}) => {
    return `${level} - ${msg}`;
  }
}

[fewieden]

@lazywithclass I also have the same expectations as @tiborbaksa.

If I create my logger with something like:

winston.createLogger({
    exitOnError: false,
    transports: [],
    format: winston.format.printf(customFormatter)
  });

I would expect if I don't specify a custom messageFormatter while adding a cloudwatch transport, that it would print in the format of the logger described above.

Currently, I need to add transport like this in order to achieve the same format as the console transport for example which is making use of the format option inside createLogger.

logger.add(new WinstonCloudWatch({
      awsRegion: 'eu-central-1',
      logGroupName:  'logger',
      logStreamName: process.env.NODE_ENV || 'development',
      messageFormatter: customFormatter
}));

[lazywithclass]

So you want to be able to do

winston.createLogger({
  exitOnError: false,
  transports: [],
  format: winston.format.printf(customFormatter)
});

and rely on Winston's default, is that correct?

[fewieden]

@lazywithclass yes that is correct, so I can use the same format in all my transports.

[lazywithclass]

@fewieden I am trying to put myself in your scenario, I wrote the following example script

var winston = require('winston'),
    WinstonCloudWatch = require('../index');


var transport = winston.createLogger({
  exitOnError: false,
  transports: [
    new WinstonCloudWatch({
      logGroupName: 'testing',
      logStreamName: 'first',
      awsRegion: 'us-east-1'
    })],
  format: winston.format.printf(function({level, message}) {
    return `${level} - ${message}`;
  })
});

transport.error('error error!');

and saw "error - error error!" in AWS CloudWatch.
I'm afraid I am missing the point you guys are trying to kindly explain me, could you please post a complete snippet that I can try to verify what needs to be done?

Thanks a lot!

[petracles]

Hey @lazywithclass, based on your example, it looks like that's what the ask from OP was - to be able to define a format once and use it for any transport (a Winston one or a WinstonCloudWatch one).

I'm curious to try your example, as I've done something similar in the past with no success. I'll give it another shot soon, and if I get it working, I can come back and post some code :)

[fewieden]

@lazywithclass in principle that's what I would like to do, but I think the problem with your example here is, that the format you specified is the same as you use for cloudwatch as default, if messageFormatter is not specified. That's why they are matching.

winston-cloudwatch/index.js

Lines 25 to 27 in 276dcdf

	var messageFormatter = options.messageFormatter ? options.messageFormatter : function(log) {
	return [ log.level, log.message ].join(' - ')
	};

Our custom format looks like this:

import { format } from 'util';

// workaround for https://github.com/winstonjs/winston/issues/1427
export function customFormatter({level, message = '', msg = '', [Symbol.for('splat')]: args = []}) {
  return `${level} - ${format(message || msg, ...args)}`;
}

Simple example

transport.info('some text');

Console Transport

Cloudwatch

Advanced example

transport.info('some text', {foo: 'bar'}, new Error('wtf'));

Console Transport

Cloudwatch

Cloudwatch with specifying messageFormatter

[lazywithclass]

About msg: we don't have that anymore in the codebase, we use message the docs were obsolete, but now I've fixed them.

I've changed my proposed example to sum up your problem as follows

var winston = require('winston'),
    WinstonCloudWatch = require('../index');

function format(message, ...rest) {
  // I am inventing a custom formatter
  return `
    ${message}
    ${rest.map(r => ` * ${r}`).join('\n')}
  `
}

function customFormatter({level, message, [Symbol.for('splat')]: args = []}) {
  return `${level} - ${format(message, ...args)}`;
}

var transport = winston.createLogger({
  exitOnError: false,
  transports: [
    new WinstonCloudWatch({
      logGroupName: 'testing',
      logStreamName: 'first',
      awsRegion: 'us-east-1'
    })],
  format: winston.format.printf(customFormatter)
});

transport.info('some text', {foo: 'bar'}, new Error('wtf'));

In AWS CloudWatch it just logs info - some text, regardless of the output of customFormatter, which would've printed something like

some text
 * [object Object]
 * Error: wtf

Do you confirm that you would like the second output to appear in AWS CloudWatch?
If so great!, otherwise please update the code I've pasted and add the expected output, so I have something that looks like a test to work on and check my work.

Thank you!

P.S.: This is one of those issues that would've been solved in 5 minutes if we were sitting at the same desk :D, but hopefully I'm getting closer to understanding.