winston-cloudwatch: messageFormatter doesn't seem to work (since Winston 3.0.0?)

To have a clean implementation I think we have to move away from the obsolete inheritance model I coded ages ago and introduce the much cleaner class model. This will also allow to get rid of old practices like utils.inherit and winston.Transport.call(this, options), and finally allow us to follow the preferred way of creating a new Transport.

One of my wildest dreams would be also to remove the horrific setInterval (what was I even thinking?!?), and introduce a better approach like @timdp did for his fork https://github.com/timdp/winston-aws-cloudwatch. But I’ll see about that.

This won’t be immediate though and will be surely marked as winston-cloudwatch v3.0.0. I am going though the changes required to make this a reality. If you have a better idea I’m listening ^^

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 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!

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?

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

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.

Try like this guys

const messageFormatter = (data) => {
  const { level, message, timestamp, ...meta } = data;
  const metatdata = `:\n${JSON.stringify(meta, null, 2)}`;
  return `${timestamp} [${level}] ${message}${metatdata}`;
};

function cloudwatch() {
  const options = { messageFormatter };
  return new winstonCloudwatch(options);
}

const logger = winston.createLogger({
  format: format.combine(format.timestamp()), // Just to allow timestamp
  transports: [cloudwatch()],
});

Besides work and university issues I’m progressing slower than usual because I’ve got some issue with mockery, I can’t get it to mock a required module (AWS)

Update: as you can see from https://github.com/lazywithclass/winston-cloudwatch/pull/130 I moved to the cleaner class syntax, and I’ve used Winston’s default formatter.

I’ll then put myself back into the green-red-green refactoring cycle, so I can hopefully remove setInterval as required for #127.

@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}`;
  }
}

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!

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!