title: Why is ARG in a DOCKERFILE not recommended for passing secrets?
body: <p>In <a href="http://docs.docker.com/engine/reference/builder/#arg">http://docs.docker.com/engine/reference/builder/#arg</a> , It recommendeds secrets are not passed through ARGS.</p>
  
  <blockquote>
    <p>Note: It is not recommended to use build-time variables for passing secrets like github keys, user credentials etc.</p>
  </blockquote>
  
  <p>At what point are secrets passed through build-time variables in danger?</p>