What would it take to add "apk" extraction to docker_build

[mattmoor]

In the pursuit of tiny images, udeb came up, but wasn't sufficient for the JRE.

We should consider whether simply using APK provides smaller footprints.

Here's where pkg_tar is extracting the deb's data: https://github.com/bazelbuild/bazel/blob/master/tools/build_defs/pkg/build_tar.py#L147

[mattmoor]

@dlorenc FYI

[dlorenc]

For java specifically, here's another example of installing a JRE without a package manager, and stripping out lots of parts:
https://github.com/frol/docker-alpine-oraclejdk8/blob/master/Dockerfile

[dlorenc]

I don't think APKs and debs will mix and match very well due to the glibc/musl difference, but it might still be worth exploring.

[mattmoor]

Yeah, I have started to introduce the nuance of "minimal" vs. "small" in my talking points.
Essentially, Alpine is smaller, but not minimal. What we're doing is minimal, but not at small.

Ultimately, if we have users with the requirement "small at all costs", who aren't concerned about compatibility with glibc, then this route might be an appealing alternative to glibc and debs, but it would require a completely new image stack.

I wonder if in the limit Bazel's cross compilation story will be what we want to key off of here.

[donmccasland]

Closing old bugs