Add Harvard Key support back to R

[doprdele]

Story Description

The original Heroku R buildpack https://elements.heroku.com/buildpacks/hmdc/heroku-buildpack-r contains Harvard Key support through Apache mod_auth_cas module. It has not yet been rearticulated as a Dockerfile buildstep. I want to re-add Harvard Key support as it is a feature that many R apps that utilize secure or confidential data require.

Helpful Context, Background

A number of our users use R in a "Shield Private Space" or "Private Space" for processing secure data and require Harvard Key in order to meet Harvard policies.

How do we test this feature so that we know that it is done?

• Harvard Key re-direction occurs when visiting a Harvard Key protected Shiny site
• AUTH_CAS_ENABLED=True enables Harvard Key, by default, AUTH_CAS_ENABLED=False disables it.

Env variables

AUTH_CAS_DOMAIN=whatever.hmdc.harvard.edu