Thanks. I'd missed that. It looks pretty close to what I want.
Just one suggestion - I'm uploading python files. It'd be nice to be able to exclude my `venv` virtual env directory from being zipped and uploaded since that's strictly for local use. From the docs I'm not sure if that's possible (I've not gone into detail with them yet).
If I can also run tests as part of the build process then I'd be sold.
It provides an API for what you're already doing with uploading zips to GCS, doing your build, and having the resulting container end up in GCR.
Disclaimer: I work at Google on GCP.