Bazel rules for "build-in-docker" (or "bid")

What is "build-in-docker" (bid)?

Bid allows you to create a build rule that runs a single bazel build action inside a Docker container.

What is bid not?

• Bid is different from https://github.com/bazelbuild/rules_docker. Those are Bazel rules for building containers.

• Bid is also different from running bazel from a container described at https://bazel.build/install/docker-container. That is a way to run the entire bazel build inside a docker container.

Why bid?

This is a refactoring of a hack I did for https://github.com/filmil/bazel-ebook.

The ebook toolchain setup was very complex. It included installing plenty of Python, pandoc and dependencies, which are notoriously hard to get right.

I worked around the whole issue by creating a Docker container which has a regular Debian system with all the tools installed, and writing bazel rules that invoke that container in build steps.

How to use bid?

Declare it in your WORKSPACE file.

Ensure your WORKSPACE file has:

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

Then append the following:

git_repository(
    name = "bazel_rules_bid",
    remote = "https://github.com/filmil/bazel-rules-bid.git",
    commit = "04b599ec790fe4572dfb851e145c791cb5022c15",
    shallow_since = "1676537869 -0800"
)
load("@bazel_rules_bid//build:repositories.bzl", "bazel_bid_repositories")
bazel_bid_repositories()

See the example in Bazel-ebook on how to use it then. Mostly you use the rule to prepend the appropriate docker command line and container name to what you actually want to run in the docker container. The script takes care that all needed directories are made available to the docker container when it runs.

The first time you run the rule, it may take considerable time for your container to get downloaded. Once it is, however, you are good to go.