exports.handler = (event, context, callback) => {
  // If we set the lambda as a proxy in the lambda config,
  // it will have the full request object in event parameter instead of the data needed

  // The context provide details of your Lambda function's execution. OPTIONAL
  const response = {
    headers: {'Control-Access-Allow-Origin': '*'},
    body: JSON.stringify({message: 'I\'m a lambda!'})
  }

  // The callback is responsible to invocation until the event loop is empty.
  // As a lambda proxy we have to return the incoming request

  callback(null, response)
}