Regression: Interacting with an on-prem store proxy fails indiscriminately

[atomcult]

Bug Description

Both SC7 and SC8 fail when attempting to interact with a store proxy using any of the currently supported subcommands. I’ve confirmed that the macaroon file generated by export-login is valid by successfully building an image from the proxy with ubuntu-image, so the issue (based on the logs below) seems to be with candid login functionality.

To Reproduce

export SNAPCRAFT_ADMIN_MACAROON="$(cat store-export-ce-team-test-20240107T001605.macaroon)"
export SNAPCRAFT_STORE_AUTH=onprem
export STORE_DASHBOARD_URL="https://store-proxy.lxd/publishergw"
export STORE_UPLOAD_URL="https://store-proxy.lxd"

snapcraft export-login store-proxy.creds

export SNAPCRAFT_STORE_CREDENTIALS="$(cat store-proxy.creds)"

snapcraft list-revisions core22

Environment

Snapcraft 7.5.4 (rev. 10085) & Snapcraft 8.0.1 (rev. 10279) Ubuntu 23.10 x86_64 6.2.16+ Kernel

snapcraft.yaml

N/A

Relevant log output

2024-01-18 16:16:17.787 Starting Snapcraft 7.5.4
2024-01-18 16:16:17.789 Storing credentials for 'snapcraft' on 'store-proxy.lxd' in keyring 'auth MemoryKeyring'.
2024-01-18 16:16:17.789 Retrieving credentials for 'snapcraft' on 'store-proxy.lxd' from keyring 'auth MemoryKeyring'.
2024-01-18 16:16:17.789 craft-store error: Credentials could not be parsed. Expected valid Candid credentials.
2024-01-18 16:16:17.789 Full execution log: '/home/jmbrock/.local/state/snapcraft/log/snapcraft-20240118-161617.786092.log'

Additional context

No response