gistfile1.js

// define the prototype that will be instantiated when the bulb is discovered
// later, we will create a ...perform function, and a ...update function.
var LIFX = exports.Device = function(deviceID, deviceUID, info) {
    console.log("create new bulb");
  var self = this;

  logger.info("create new bulb",deviceID, deviceUID, info);
  self.whatami = info.deviceType;
  self.deviceID = deviceID.toString();
  self.deviceUID = deviceUID;
  self.name = info.device.name;
  self.getName();

  self.bulb = info.bulb;

  broker.subscribe('actors', function(request, taskID, actor, perform, parameter) {
    if (actor !== ('device/' + self.deviceID)) return;

    if (request === 'perform') return self.perform(self, taskID, perform, parameter);
  });
};
exports.start = function() {
    console.log("start");
  var logger2 = utility.logger('discovery');

  steward.actors.device.lighting.LIFX = steward.actors.device.lighting.LIFX ||
      { $info     : { type: '/device/lighting/LIFX' } };

  steward.actors.device.lighting.LIFX.led =
      { $info     : { type       : '/device/lighting/LIFX/led'
                    , observe    : [ ]
                    , perform    : [ 'off', 'on' ]
                    , properties : { name       : true
                                   , status     : [ 'waiting', 'on', 'off' ]
                                   , color      : { model: [ { rgb         : { r: 'u8', g: 'u8', b: 'u8' } }
                                                           , { hue         : { hue: 'degrees', saturation: 'percentage' } }
                                                           ]
                                                  }
                                   , brightness : 'percentage'
                                   }
                    }
      , $validate : { perform    : validate_perform }
      };
  devices.makers['/device/lighting/LIFX/led'] = LIFX;

// LIFX: when the hardware driver discovers a new bulb, it will call us.
// LIFX: or if the low-level driver needs to be polled, then create a 'scan' function and call it periodically.
  lx = lifx.init().on('bulb', function(bulb) {
    console.log("found new bulb", bulb);
        var info;

        info = { source     : 'LIFX'
               , bulb       : bulb
               , device     : { url          : null
                              , name         : bulb.name
                              , manufacturer : "LIFX"
                              , model        : { name        : bulb.name
                                               }
                              , unit         : { serial      : bulb.lifxAddress
                                               , udn         : 'LIFX:' +  + bulb.lifxAddress.toString('hex')
                                               }
                              }
              , deviceType  : '/device/lighting/LIFX/led'

              };

// if multiple bulb types, update info.deviceType as appropriate
    info.url = info.device.url;
    info.deviceType = '/device/lighting/LIFX/led';
    info.id = info.device.unit.udn;
    if (!!devices.devices[info.id]) return;

    logger2.info("LIFX new bulb:", info.device.name);
    devices.discover(info);
  }).on('bulbstate', function(bulbstate) {
    console.log("bulbstate", bulbstate);
    var dev,  udn;

    udn = 'LIFX:' + bulbstate.bulb.lifxAddress.toString('hex');
    console.log("bulbstate", udn);
    if (!devices.devices[udn]) return;
    dev = devices.devices[udn].device;
    console.log("bulbstate", dev);
    bulb.logger("bulbstate bulb", dev);
    dev.update(dev, bulbstate.state);
  }).on('bulbonoff', function(bulbonoff) {
    console.log("bulbstate", bulbonoff);
    var dev,  udn;

    udn = 'LIFX:' + bulbonoff.bulb.lifxAddress.toString('hex');
    if (!devices.devices[udn]) return;
    dev = devices.devices[udn].device;
    dev.logger(dev);
    dev.update(dev, { power: bulbonoff.on ? 65535 : 0 });
  }).logger = logger2;
};

gistfile2.txt

found new bulb { lifxAddress: <Buffer d0 73 d5 00 29 1b>, name: 'Hallway' }
info: [discovery] LIFX new bulb: Hallway
bulbstate { bulb: { lifxAddress: <Buffer d0 73 d5 00 29 1b>, name: 'Hallway' },
  state: 
   { hue: 0,
     saturation: 0,
     brightness: 3763,
     kelvin: 4500,
     dim: 0,
     power: 65535,
     bulbLabel: 'Hallway',
     tags: <Buffer 00 00 00 00 00 00 00 00> } }
bulbstate LIFX:d073d500291b
bulbstate undefined
alert: [steward] exception diagnostic=Cannot call method 'update' of undefined
alert: [steward] exception stack=[{"fileName":"/home/pi/steward/steward/devices/devices-lighting/lighting-lifx.js","lineNumber":222,"functionName":"Lifx.lifx.init.on.on.on.udn","typeName":"Lifx","methodName":"lifx.init.on.on.on.udn","columnNumber":9,"native":false},{"fileName":"events.js","lineNumber":95,"functionName":"Lifx.EventEmitter.emit","typeName":"Lifx","methodName":"EventEmitter.emit","columnNumber":17,"native":false},{"fileName":"/home/pi/steward/steward/node_modules/lifx/lifx.js","lineNumber":139,"functionName":"Lifx.foundBulb","typeName":"Lifx","methodName":"foundBulb","columnNumber":7,"native":false},{"fileName":"/home/pi/steward/steward/node_modules/lifx/lifx.js","lineNumber":89,"functionName":"Lifx._gotPacket","typeName":"Lifx","methodName":"_gotPacket","columnNumber":9,"native":false},{"fileName":"/home/pi/steward/steward/node_modules/lifx/lifx.js","lineNumber":80,"functionName":"","typeName":"Gateway","methodName":null,"columnNumber":31,"native":false},{"fileName":"events.js","lineNumber":98,"functionName":"Gateway.EventEmitter.emit","typeName":"Gateway","methodName":"EventEmitter.emit","columnNumber":17,"native":false},{"fileName":"/home/pi/steward/steward/node_modules/lifx/lifx.js","lineNumber":180,"functionName":"","typeName":"Socket","methodName":null,"columnNumber":8,"native":false},{"fileName":"events.js","lineNumber":95,"functionName":"Socket.EventEmitter.emit","typeName":"Socket","methodName":"EventEmitter.emit","columnNumber":17,"native":false},{"fileName":"_stream_readable.js","lineNumber":746,"functionName":"","typeName":"Socket","methodName":null,"columnNumber":14,"native":false},{"fileName":"events.js","lineNumber":92,"functionName":"Socket.EventEmitter.emit","typeName":"Socket","methodName":"EventEmitter.emit","columnNumber":17,"native":false}]
uncaught exception: TypeError: Cannot call method 'update' of undefined

try this for the info assignment

    info = { source     : 'LIFX'
           , lx         : lx
           , bulb       : bulb
           , device     : { url          : null
                          , name         : bulb.name
                          , manufacturer : "LIFX"
                          , model        : { name        : bulb.name
                                           , description : ''
                                           , number      : ''
                                           }
                          , unit         : { serial      : bulb.lifxAddress.toString('hex')
                                           , udn         : 'LIFX:' + bulb.lifxAddress.toString('hex')
                                           }
                          }
           }; 
    info.url = info.device.url;
    info.deviceType = '/device/lighting/LIFX/led';
    info.id = info.device.unit.udn;
    if (!!devices.devices[info.id]) return;

No change. Should I put a callback like this: devices.discover(info, cb); and see how it gets called?