containerkeys v1 auth with Duplicity, tested with a local swift AIO install /w middleware installed.
$ export SWIFT_USERNAME="test:testcontainer:Full-Key"
$ export SWIFT_PASSWORD="mykeyiscool"
$ export SWIFT_AUTHURL="http://192.168.122.95:8080/keys_auth/"
$ export SWIFT_AUTHVERSION="1"
$ duplicity --no-encryption containerkeys swift://testcontainer
Local and Remote metadata are synchronized, no sync needed.