Custom log levels

I’m unable to get custom log levels to work. I’ve tried updating node, installing winston via npm, and cloning the winston repo. The example code in the readme for custom levels runs without any errors:

 var myCustomLevels = {
    levels: {
      foo: 0,
      bar: 1,
      baz: 2,
      foobar: 3
    },
    colors: {
      foo: 'blue',
      bar: 'green',
      baz: 'yellow',
      foobar: 'red'
    }
  };

  var customLevelLogger = new (winston.Logger)({ levels: myCustomLevels.levels }); 
  customLevelLogger.foobar('some foobar level-ed message');

but nothing prints out into console.

I’ve also tried a variation of

  var logger = new (winston.Logger)({
    transports: [
      new (winston.transports.Console)(),
      new (winston.transports.File)({ filename: 'somefile.log' })
    ]
  });

with logger.addLevels() but I get the same results. The new log levels I pass do nothing.

The originals (info, debug, etc.) are not available - just as expected.

[JCBarry]

So I was able to dig into this a bit more and figure out a bit more about what’s going on. From all the code samples I’ve seen in the documentation and this thread, the expectation is that setting the default level on the logger is the only required configuration to use custom levels.

I found that not only do you need to set the default logger level but also the default transport level to get the examples above and in the documentation to work as expected. From your example above, changing this line to the following:

transports: [new winston.transports.Console({level: foobar})]

This is mostly to do with this conditional in lib/winston/logger.js:

if ((transport.level && self.levels[transport.level] <= self.levels[level]) 
    || (!transport.level && self.levels[self.level] <= self.levels[level])) 

Since the default transport.level is set to info in lib/winston/transports/transport.js here:

this.level = options.level  || 'info';

You’ll need to do one of two things to use custom levels, in addition to defining the default level on the logger:

1. Define a default level on your transport
2. Include an info level in your custom levels

If this isn’t by design, it can be fixed by altering the conditional and the forced variable assignment. If it is by design, the documentation should be tweaked a bit too avoid confusion.

I’d be happy to help accomplish either, just let me know which direction you’d like to head. Thanks!

[lucasbagatini]

If anybody is wondering how to keep the default levels and add more:

const myCustomLevels = {
  levels: {
    ...winston.config.npm.levels,
    myCustomLevel: 7,
  },
  colors: {
    ...winston.config.npm.colors,
    myCustomLevel: 'blue',
  },
};