dprint-plugin-buildifier

Wrapper for buildifier for use as a formatting plugin in dprint. It formats Bazel and Starlark files (BUILD, MODULE.bazel, WORKSPACE, .bzl, ...) exactly like the buildifier CLI does, since it's buildifier's own Go code compiled to Wasm with TinyGo.

Install

Install and setup dprint.

Then in your project's directory with a dprint.json file, run:

dprint add buildifier

Note: You do not need buildifier installed globally as dprint will run buildifier from the .wasm file in a sandboxed environment.

Files

The plugin formats the same files buildifier finds when walking a directory:

Files	Formatted as
BUILD, BUILD.bazel, WORKSPACE, WORKSPACE.bazel, WORKSPACE.bzlmod, MODULE.bazel, *.MODULE.bazel, REPO.bazel and VENDOR.bazel	Bazel files, which get buildifier's rewrites for them, like sorting deps and putting name first in a rule call
.bzl, .star and .sky files	Starlark files, which only get the rewrites that apply to all Starlark, like sorting load statements

buildifier picks how to format a file from its name, so files matched through dprint's associations (ex. a Tiltfile) are formatted as plain Starlark.

buildifier also formats .BUILD files (ex. third_party/zlib.BUILD), but the plugin doesn't match them by default, since dprint matches extensions case insensitively and .build would also claim files like meson.build. They can be added with the plugin's associations.

Configuration

buildifier has no style options, so there's nothing to configure for the formatting itself. Like other dprint plugins, it uses dprint's newLineKind:

{
  "buildifier": {
    "newLineKind": "auto"
  }
}

Option	Default	Description
newLineKind	lf	lf, crlf, or auto to keep the newline kind found at the end of the file's last line. Uses the global newLineKind when not specified.

buildifier itself always outputs line feeds, and reads a carriage return line feed as two newlines, so the plugin turns them into line feeds before formatting.

The plugin formats like buildifier with its default settings. It doesn't read .buildifier.json files, since it can't read files, so buildifier's custom tables aren't supported, and it doesn't lint (--lint=fix).

For an overview of the config, see https://dprint.dev/plugins/buildifier/config/

JS Formatting API

• JS Formatter - Browser/Deno and Node
• npm package

Versioning

This repo automatically upgrades to the latest version of buildifier once a day. You can check which version of buildifier is being used by looking at the github.com/bazel-contrib/buildtools/v10 entry in the go.mod file in this repo:

https://github.com/dprint/dprint-plugin-buildifier/blob/main/go.mod

At the moment, the version of this plugin does not reflect the version of buildifier.

Development

The plugin is built with TinyGo, which produces a much smaller module than the Go compiler, and one that has no imports, so it doesn't rely on the dprint CLI providing WASI.

go test ./...
deno run -A ./scripts/build.ts # outputs target/plugin.wasm
deno run -A ./scripts/test_wasm.ts # tests target/plugin.wasm

The build uses a local tinygo (which needs binaryen's wasm-opt) when there is one, and otherwise the TinyGo Docker image.

The tests format the inputs of buildtools' own printer tests and compare them with its golden files, read from the buildtools module in the Go module cache. go test does this with the Go code, and scripts/test_wasm.ts does it with the built Wasm file.

Credits

• buildifier by Google, under the Apache License 2.0.
• The plugin interface is adapted from dprint-plugin-shfmt, which adapted it from Jake Bailey's dprint-plugin-gofumpt.

License

This project is licensed under the MIT License - see the LICENSE file for details. See third_party for the licenses of the code it includes.