Bazel Quickstart

This is a template repository for starting a new project that uses Bazel as the build system. It contains a simple Rust project that is built using Bazel.

Building & Testing

This repository uses Bazel as the build system. To build the code, run:

bazel build //...

To run the tests, run:

bazel test //...

Linting & Formatting

Most of the linters can be run with the --config=lint flag. For example:

bazel test --config=lint //...

The Bazel file formatter, buildifier, does not run as an aspect, so it needs to be run separately.

bazel run buildfmt.check

To run all of the formatters:

bazel run fmt

Updating dependencies

Updating Rust crates

Modify the Cargo.toml file to update the dependencies.

Note that there is no need to overly specify versions of dependencies as Bazel will use the versions specified in the Cargo.lock file. It is recommended to use versions such as "0" or "0.1" for dependency specifications so that Cargo can find the latest minimal set of dependencies that satisfy the requirements.

Add @crates_io//:crate_name to the deps attribute of the rust_library or rust_binary rule in the BUILD.bazel file.

Repinning dependencies

To update the dependencies, run:

bazel mod deps --lockfile_mode=refresh

Re-generate the rust_project.json file by running:

bazel run gen_rust_project

Project Structure

The project structure is intended to support a monorepo with multiple projects and multiple languages.

Each project should have its own directory in the root of the repository. The exception is the tools directory, which contains bazel rules and other build functionality.

Shared code should be placed in a common directory which is specific to the company or organization. For instance, if your company is named "Cloud Kitchen", you might have a directory named ck/ that contains shared code. As a last resort name it common/ or shared/ but not that this will be in all of your import paths. This template uses ss/ as the shared code directory.

Rust Code

Rust code is structured as one crate per directory except for the cmd/ directories which contain binaries. The binary name is expected to be the same as rust file name.

# my_project/cmd/BUILD.bazel
load("//tools/rust:defs.bzl", "rust_binary")

rust_binary(
    # This corresponds to the file name `my_binary.rs`.
    name = "my_binary",
    # You can optionally override the `srcs` attribute to customize the sources but it is discouraged.
    deps = [
        "//my_project/lib",
    ],
)