Configurations for Chrome Operation services

IMPORTANT: This branch only has an effect for branches that have projects set up in https://chrome-internal.googlesource.com/infradata/config/+/HEAD/configs/luci-config/projects.cfg

This directory contains chromium project-wide configurations for Chrome Operations services. For example, cr-buildbucket.cfg defines builders.

Currently active version can be checked at https://luci-config.appspot.com/#/projects/chromium .

Starlark configs

The configuration is written using starlark, which is executed using lucicfg to generate the raw cfg files located in generated. See https://chromium.googlesource.com/infra/luci/luci-go/+/HEAD/lucicfg/doc/README.md for more information on lucicfg/starlark.

The starlark configuration is rooted in main.star and dev.star, which execute other starlark files to generate a subset of the LUCI service configuration files. A presubmit check enforces that the generated files are kept in sync with the output of the starlark configuration.

The configuration rooted at main.star defines the LUCI services configuration for the chromium project on the production instance of LUCI. The configuration is responsible for generating the raw configuration files that do not end in -dev.cfg as well as the markdown file cq-builders.md. Starlark files in the following directories are consumed by the configuration:

• lib - Mostly lists of hard-coded constants.
• targets - A local lucicfg package containing definitions of chromium targets and tests that will be executed by builders. See its README.md for information on how to use the package in other projects.
• subprojects - Definitions of LUCI entities.
• generators - Definitions of lucicfg generators that do various things to post-process the LUCI configuration before the output files are generated. (e.g. generate no-op jobs to workaround limitations of our recipe config) or generate additional files (e.g. the CQ builders markdown document).
• validators - Definitions of lucicfg generators that perform additional validation on the the LUCI configuration (e.g. ensure all builders are added to at least one console).
• outages - Definitions of config settings for operations common when handling outages.

The configuration rooted at dev.star defines the LUCI services configuration for the chromium project on the dev instance of LUCI. This configuration consumes starlark files under the dev directory and is responsible for generating the raw configuration files ending in -dev.cfg.

Starlark libs

Much of the starlark configuration here uses libraries defined in a separate infra/chromium.git repo. These libraries traverse and manipulate lucicfg's internal graph to represent components of Chromium's infra (e.g. nodes for things like builders and tests, and links between related elements). This code is in a separate repo so it can be shared and reused elsewhere, mainly src-internal.

Normally, when generating the LUCI configs here, the infra/chromium.git repo is fetched on-demand using lucicfg's package system. However, if you have that repo checked out locally and want to re-generate the configs here using it instead, you can do so via:

lucicfg generate -repo-override chromium.googlesource.com/infra/chromium/+/refs/heads/main=/path/to/local/infra/chromium/checkout main.star

VS Code

In order to get syntax highlighting, the Bazel can be installed.

In order to get "go to definition" to work, an extra language server needs to be available for the Bazel extension. This currently requires applying a custom patch on top of the bazel-lsp project and compiling the language server binary, then using it via settings.json in VS Code. See the //tools/vscode/bazel_lsp/README.md for more details.