Multiple log files with Winston?

Question

Multiple log files with Winston?

We'd like to use Winston for our logging in Node.js. But, we can't figure out how to have two log files: one for just errors, and one for everything else.

Doing this the naive way doesn't work, however: adding multiple winston.transports.File transports gives an error.

Others have run into this problem, with vague hints of a solution, but no real answer.

Any ideas?

node.js
logging
flatiron.js
winston

Answer 1

Unfortunately, the patch that pesho mentioned seems to be still not included in the official version (see stephenbeeson's comment in the pull request #149).

So, I used a workaround instead. As winston compares the name attributes, you can fool it by defining the name yourself:

winston = require 'winston'

logger = new winston.Logger
  transports: [
    new winston.transports.File
      name: 'file#debug'
      level: 'debug'
      filename: '/tmp/debug.log'
    new winston.transports.File
      name: 'file#error'
      level: 'error'
      filename: '/tmp/error.log'
  ]
logger.error 'error' # both logs
logger.debug 'debug' # on debug log

Maybe not elegant, but at least it works.

Answer 2

I just sent a pull request that allows using multiple File transports in one logger. https://github.com/flatiron/winston/pull/149

It is already merged into flatiron/winston.

You can also use my forked repo: https://github.com/pdobrev/winston

Answer 3

In the meantime, you can implement a rudimentary wrapper using the same interface like so

var winston = require('winston');
var configs = require('./env.js');

var debug = new winston.Logger({
  levels: {
    debug: 0
  },
  transports: [
    new (winston.transports.File)({ filename: configs.PATH_TO_LOG, level: 'debug'}),
    new (winston.transports.Console)({level: 'debug'})
  ]
});

var info = new winston.Logger({
  levels: {
    info: 1
  },
  transports: [
    new (winston.transports.File)({ filename: configs.PATH_TO_LOG, level: 'info'}),
    new (winston.transports.Console)({level: 'info'})
  ]
});

var warn = new winston.Logger({
  levels: {
    warn: 2
  },
  transports: [
    new (winston.transports.File)({ filename: configs.PATH_TO_LOG, level: 'warn'}),
    new (winston.transports.Console)({level: 'warn'})
  ]
});

var error = new winston.Logger({
  levels: {
    error: 3
  },
  transports: [
    new (winston.transports.File)({ filename: configs.PATH_TO_LOG, level: 'error'}),
    new (winston.transports.Console)({level: 'error'})
  ]
});

var exports = {
  debug: function(msg){
    debug.debug(msg);
  },
  info: function(msg){
    info.info(msg);
  },
  warn: function(msg){
    warn.warn(msg);
  },
  error: function(msg){
    error.error(msg);
  },
  log: function(level,msg){
    var lvl = exports[level];
    lvl(msg);
  }
};

module.exports = exports;

This will cover the basic winston API. could be extended for metadata and so on...