Bazel toolchain configuration for RBE

DO NOT EDIT THIS DIRECTORY BY HAND.

All files in this directory (excluding this file) are generated with the rbe_configs_gen CLI tool. Keep reading for details.

This directory contains a Bazel toolchain configuration for RBE. It is generated with the rbe_configs_gen CLI tool from the bazel-toolchains repository.

This directory is referenced from //.bazelrc.

Upgrading to a new Bazel version

Take the following steps to upgrade to a new Bazel version.

Step 1

Update the //.bazelversion file with the new Bazel version. This file is read by Bazelisk (for those engineers who use bazelisk as a replacement for bazel).

Step 2

Regenerate the //bazel/rbe directory with the rbe_configs_gen CLI tool (installation instructions below):

# Replace the <PLACEHOLDERS> as needed.
$ rbe_configs_gen \
      --bazel_version=<BAZEL VERSION> \
      --toolchain_container=gcr.io/skia-public/rbe-container-skia-infra@sha256:<HASH OF MOST RECENT IMAGE> \
      --output_src_root=<PATH TO REPOSITORY CHECKOUT> \
      --output_config_path=bazel/rbe \
      --exec_os=linux \
      --target_os=linux

Example:

$ rbe_configs_gen \
      --bazel_version=4.1.0 \
      --toolchain_container=gcr.io/skia-public/rbe-container-skia-infra@sha256:5deebf6be17a276a44580301daacdbb580c0b2b25eb4b0dea7e51f8011ec12ff \
      --output_src_root=$HOME/buildbot \
      --output_config_path=bazel/rbe \
      --exec_os=linux \
      --target_os=linux

If rbe_configs_gen fails, try deleting all files under //bazel/rbe (except for this file) and re-run rbe_configs_gen.

Step 3

Run bazel run //:buildifier and fix any linting errors on the generated files (e.g. move load statements at the top of the file, etc.)

Step 4

Update the bazel-toolchains repository version imported from //WORKSPACE to match the new Bazel version.

How to install the rbe_configs_gen CLI tool

Clone the bazel-toolchains repository outside of the Buildbot repository checkout, build the rbe_configs_gen binary, and place it on your $PATH:

$ git clone https://github.com/bazelbuild/bazel-toolchains

$ cd bazel-toolchains

# This assumes that $HOME/bin is in your $PATH.
$ go build -o $HOME/bin/rbe_configs_gen ./cmd/rbe_configs_gen/rbe_configs_gen.go