This is what we do at fly.io: https://github.com/superfly/fly

It's based on node.js right now. It's a bit clunky, but we have many success stories of customers running it locally, on their CI and deploying to infrastructure.

Currently the open source version is not the same as the production version (due to the distributed nature of our platform.) We're working on fixing that very soon and going all-in open source.