bazel-nix-example VS buildah

I put together an example that mixes Nix and Bazel a couple of years ago: https://github.com/jvolkman/bazel-nix-example

Nix is used to build a base Docker image, and Bazel builds layers on top.

It sounds so cool, but then I don’t get out of the base image before you’re writing your own Python launcher in a heredoc in a shell script in a docker image builder in a mix derivation[0]? Curiosity compels me to ask: how did all that become necessary?

[0]: https://github.com/jvolkman/bazel-nix-example/blob/e0208355f...

Not sure of any writing that ties all of the pieces together, but I made a small example for you: https://github.com/jvolkman/bazel-nix-example

For the task of building the graph image, my first idea was to rely on buildah. In fact, our design was already heavily relying on containers/image for all things regarding copying images from one registry to the other, or from one registry to an archive. The obvious choice was to use the same suite of modules in order to keep dependencies to a minimum.

I appreciate that podman can run daemonless, but I've gotten tired of waiting for them to implement heredoc support and have continued to use docker.

You do realize that, under the hood, buildah uses a container engine (runc by default)? See https://github.com/containers/buildah/blob/main/docs/buildah...

buildah

I found this small tutorial: https://github.com/containers/buildah/blob/main/docs/tutorials/04-include-in-your-build-tool.md and it works.

# https://github.com/containers/buildah/issues/3666 volume /var/lib/containers

Last week, Buildah version 1.29 was also released. The prune command has been added to clean intermediate images as well as the build and mount cache.  Support for the –group-add option to the from and build commands was added. One useful feature of this, it to use the –group-add keep-groups option, which allows rootless users to take advantage of their group access to file and devices mounted into the build containers. And the –cache-from and –cache-to options for the build command now allow for multiple sources. This can be used to improve the speed of builds, especially in CI/CD environments.

Unfortunately this syntax is not generally supported yet - it's only supported with the buildkit backend and only landed in the 1.3 "labs" release. It was moved to stable in early 2022 (see https://github.com/moby/buildkit/issues/2574), so that seems to be better, but I think may still require a syntax directive to enable.

Many other dockerfile build tools still don't support it, e.g. buildah (see https://github.com/containers/buildah/issues/3474)

Useful now if you have control over the environment your images are being built in, but I'm excited to the future where it's commonplace!

For more information regarding the bundled tools see: CRI tools.