[costrouc]

I really like this. I think it is a great compromise between the limitations of docker and everything packaged in one file while taking advantage of nix. I'm curious about one other optimization that could be made.

You could instead look at the dependency graph of several nix docker builds and increase the cache reuse even more from that.

[roberthensing]

This approach is already optimal for up to around 40 or 120 packages, depending on whether you want to support old Docker versions.

"Where before you wouldn’t bother trying to have your application and database images share layers, with Nix the layer sharing is completely automatic."