code: function(callback) {
  
    log('Connecting...');
    MongoClient.connect(dbUrl, dbOptions, function(err, dbConn) {
      
      if(err) {
        log('Cannot connect: ' + err);
        callback(err);
        return;
      } 
      
      log('Connected!');
      isConnected = true;
      db = dbConn;
  
      // http://stackoverflow.com/a/18715857/446681
      db.on('close', function() {
        log('Connection was closed!!!');
        isConnected = false;
      });
  
      log('Executing...');
      callback(null, db);
    
    });
  
  }
docs: by default don't log