How to do domains...

domain-example.js

// based on an example by @mikeal

var http = require('http')
  , domain = require('domain')
  ;

module.exports = function (handler) {
  var server = http.createServer(function (req, resp) {
    var d = domain.create()
    
    // add these to the domain
    // explicitely so they dont
    // get mixed into other domains
    domain.add(req)
    domain.add(resp)
    
    d.run(function () {
      handler(req, resp)
    })
    
    d.on('uncaughtException', function (e) {
      // cleanup io, end streams
      // don't cascade to the server
      // or root domain
      d.dispose()
      
      d.once('dispose', function () {
        // give a chance for streams
        // and other things to end
        // gracefully - eg. remove a half
        // written file, rollback a transaction
        process.exit()
      })
    })
    
    d.on('error', function (err) {
      console.error(err)
      resp.statusCode = 500
      resp.end()
      
      if(d.listeners('error').length == 1) {
        d.emit('uncaughtException', err)
      }
    })
  })
  return server
}

@izs how important is it to call dispose() in this case?

@ritch it's not a given that you should bring down the process.

True, also dispose() shouldn't be a given. Updated to wrap those in an uncaughtException event.