title: S3 Bucket Notification or CloudWatch Event Rule to call a Lambda on Object level changes?
body: <p>I need to start a Lambda Function when an object has been created on an S3 Bucket. I found 2 solutions to do this.</p>
  
  <ol>
  <li>Using <code>AWS::S3::Bucket NotificationConfiguration</code>.</li>
  <li>Using a CloudWatch <code>AWS::Events::Rule</code>.</li>
  </ol>
  
  <p>They both seem to do exactly the same thing, which is to track specific changes and launch a Lambda Function when it happens. I could not find any information on which one should be used. I'm using <code>Cloud Formation Template</code> to provision the Lambda, the S3 Bucket and the trigger.</p>
  
  <p>Which one should I use to call a Lambda on Object level changes and why?</p>