Unable to use Rackspace CloudFiles external storage

For several versions of NextCloud, we’ve been unable to use our Rackspace CloudFiles external storage. I took some time today, and was able to use the occ command to enable debug logging and to test.

Whenever I trigger a test of the mount point, this appears in the logging:

Debug no app in context Exception: “password” is a required option, but it was not provided
2019-05-22T13:46:57+1000
Info no app in context External storage not available: “password” is a required option, but it was not provided
2019-05-22T13:46:57+1000

However, Rackspace authenticated storage (see https://docs.nextcloud.com/server/16/admin_manual/configuration_files/external_storage/openstack.html ) does NOT use a password, instead, it uses an API Key. Other OpenStack authentication does require a password, as far as I can tell.

I interpret this as a code update relating to OpenStack has unfortunately blocked use of non-password OpenStack authentication. Is anyone able to help me with this?

I’ve looked into the OpenStack code used in Nextcloud, and found this documentation:

https://php-openstack-sdk.readthedocs.io/en/identity-v2/services/identity/v2/authentication.html

It seems that by default OpenStack uses v3 authentication, and needs to be instructed to use v2 for Rackspace.