using node's process to emit events to log stuff from anywhere

process.logger.js

// use like this:
// process.emit( 'app:log', module, arg1, arg2, ..., argN );

var Module = require('module');

function logConsole(method, module) {
  var args = [(new Date()).toJSON(), method];
  var index = 1;

  if (module instanceof Module) {
    args.push(module.id);
    index = 2;
  }

  args.push.apply(args, Array.prototype.slice.call(arguments, index));

  console.log.apply(console, args);
}

['debug', 'error', 'info', 'log', 'warn'].forEach( function(consoleMethod) {
  process.on('app:' + consoleMethod, logConsole.bind(null, consoleMethod.toUpperCase()));
} );

FWIW you should avoid Array.prototype.slice.call(arguments, index) style calls if you care about performance since that will make logConsole unoptimizable by v8. Creating a new array and appending to it in a for-loop will avoid this deoptimization.

The module depd will emit deprecation events on process if there is a listener, automatically suppressing output to STDERR for centralized logging in mind similar to this.

Can you please specify which versions of node are supported? I cant get it working in 6.6.0

WHy

In case it's of interest we've implemented this approach, with some sugar, and browser compatibility, in https://github.com/stencila/logga

Hey @nokome,

My friend @jeffwad — whom I commented above as, having the original idea for this — and I had completely forgotten about it when I got an email notification of your comment from github. 😅

I'm glad posting it gave you some value/inspiration, however small... 😊