One idea would be to add some logic to bioviz.org/connect so that if the various CyVerse resources are down we prevent users from logging in. This could be accomplished using the webhooks available through https://status.cyverse.org/.

The Webhooks in https://status.cyverse.org/ seems like a good solution for CAS login issues because they provide APIs specifically CAS status. However, they do not seem to have specific webhooks for Terrain API error status. In the Discovery Environment section, Cyverse has a status webhook for their website but I am not sure if it is for Terrain or Tapis(previously Agave). We could just subscribe to the CAS service status and redirect users to a "broken robot" page in case it is not operational.

Note: Cyverse is using https://status.io/ infrastructure to run the webhooks.

To redirect users in case of an outage or an error in any of the Terrain APIs, we could create a "broken robot" error page to redirect users.

1) Any errors caused due to access issues are caught in getSessionId function in views.py as the getAccessToken API is called from this function.
2) Issues about user data are caught in getRootPathUser in views.py(or getUserDetails function in getUserDetail.py). This function is used to get the root path of the user's file directory and the only parameter passed here is the access token.

Redirecting users to the error page upon receiving an error in these two functions makes a lot of sense to me because there is not a lot of mistakes that we, as developers, or the users can make in these API calls. So the errors could only most certainly come from Cyverse. Currently, we are handling only the authorization errors in these functions.