Heroku custom maintenance page
We use standard heroku features to supply a custom branded static HTML “down for maintenance” page to heroku.
heroku docs:
Our docs: https://github.com/sciencehistory/scihist_digicoll/tree/master/static_html
At this time, due to a bug in heroku – if you want to go back to heroku default maintenancce page (say we’ve accidentally deleted ours from S3 or something), you have to explicitly set heroku config var MAINTENACE_PAGE_URL to the value for heroku’s default page (instead of just unsetting it).
heroku config:set MAINTENANCE_PAGE_URL=//www.herokucdn.com/error-pages/maintenance-mode.html
This workaround given by heroku support at https://help.heroku.com/tickets/1007975