How to specify proxy for buildpacks image download

[cz4rny]

So how can I make the buildpack stack to use a proxy when downloading the base:cnb image? I’m hitting the Docker Hub pull limit. I’ve got both premium-tier creds to combat this, but also an internal corporate proxy which would be even better. Didn’t find anything in the documentation.

However I don’t know how to make the builder image use this proxy pass-through mirror. The error I’m seeing:

ERROR: failed to build: invalid run-image 'index.docker.io/paketobuildpacks/run:base-cnb': Error response from daemon: Head "https://registry-1.docker.io/v2/paketobuildpacks/run/manifests/base-cnb": toomanyrequests: too many failed login attempts for username or IP address

I’ve asked on the Paketo Slack, but it seems that it’s CNB’s code that is using the builder.toml somehow downloads the images from there.