title: Google Cloud ML Engine: Apply Custom Function Before Training / Predicting
body: <p>I currently pre-process some data on my laptop before passing it to ML Engine for training. Is it possible to apply a custom pre-processing function to my data and then train, all within ML Engine?</p>
  
  <p>So instead of these steps:</p>
  
  <ol>
  <li><p>Pre-process data on laptop.</p></li>
  <li><p>Send pre-processed data to ML engine for training.</p></li>
  </ol>
  
  <p>I would do:</p>
  
  <ol>
  <li><p>Define pre-processing function for ML Engine</p></li>
  <li><p>Send raw data to ML Engine, where it will:</p>
  
  <p>a) pre-process my data by applying the function I've specified and</p>
  
  <p>b) train on that data</p></li>
  </ol>
  
  <p>Is this possible and, if so, how would I do it?  I don't see anything in the docs.</p>
  
  <p>Thanks!</p>