If you are using Bazel's legacy external dependency mechanism (i.e., listing your external
dependencies in the WORKSPACE
file), this document describes how to get started. Otherwise, please
use the quickstart instructions in the README.md
.
- Add declarations to your
WORKSPACE
file - Create a minimal
Package.swift
file. - Add Gazelle targets to
BUILD.bazel
at the root of your workspace. - Resolve the external dependencies for your project.
- Create or update Bazel build files for your project.
- Build and test your project.
- Check-in
Package.resolved
,swift_deps_index.json
, andswift_deps.bzl
.
Update the WORKSPACE
file to load the dependencies for rules_swift_package_manager,
rules_swift and Gazelle. The snippet that you need can be found on the release
page.
The WORKSPACE
boilerplate loads a file called swift_deps.bzl
. The Gazelle plugin will
populate it, shortly. For now, create the file with the follwing contents:
# Contents of swift_deps.bzl
def swift_dependencies():
pass
Create a minimal Package.swift
file that only contains the external dependencies that are directly
used by your Bazel workspace.
// swift-tools-version: 5.7
import PackageDescription
let package = Package(
name: "my-project",
dependencies: [
// Replace these entries with your dependencies.
.package(url: "https://github.com/apple/swift-argument-parser", from: "1.2.0"),
.package(url: "https://github.com/apple/swift-log", from: "1.4.4"),
]
)
The name of the package can be whatever you like. It is required for the manifest, but it is not used by rules_swift_package_manager. If your proejct is published and consumed as a Swift package, feel free to populate the rest of the manifest so that your package works properly by Swift package manager. Just note that the Swift Gazelle plugin does not use the manifest to generate Bazel build files, at this time.
Add the following to the BUILD.bazel
file at the root of your workspace.
load("@bazel_gazelle//:def.bzl", "gazelle", "gazelle_binary")
load("@rules_swift_package_manager//swiftpkg:defs.bzl", "swift_update_packages")
# Ignore the `.build` folder that is created by running Swift package manager
# commands. The Swift Gazelle plugin executes some Swift package manager
# commands to resolve external dependencies. This results in a `.build` file
# being created.
# NOTE: Swift package manager is not used to build any of the external packages.
# The `.build` directory should be ignored. Be sure to configure your source
# control to ignore it (i.e., add it to your `.gitignore`).
# gazelle:exclude .build
# This declaration builds a Gazelle binary that incorporates all of the Gazelle
# plugins for the languages that you use in your workspace. In this example, we
# are only listing the Gazelle plugin for Swift from rules_swift_package_manager.
gazelle_binary(
name = "gazelle_bin",
languages = [
"@rules_swift_package_manager//gazelle",
],
)
# This macro defines two targets: `swift_update_pkgs` and
# `swift_update_pkgs_to_latest`.
#
# The `swift_update_pkgs` target should be run whenever the list of external
# dependencies is updated in the `Package.swift`. Running this target will
# populate the `swift_deps.bzl` with `swift_package` declarations for all of
# the direct and transitive Swift packages that your project uses.
#
# The `swift_update_pkgs_to_latest` target should be run when you want to
# update your Swift dependencies to their latest eligible version.
swift_update_packages(
name = "swift_update_pkgs",
gazelle = ":gazelle_bin",
generate_swift_deps_for_workspace = True,
update_bzlmod_stanzas = False,
)
# This target updates the Bazel build files for your project. Run this target
# whenever you add or remove source files from your project.
gazelle(
name = "update_build_files",
gazelle = ":gazelle_bin",
)
Resolve the external dependencies for your project by running the following:
$ bazel run //:swift_update_pkgs
Generate/update the Bazel build files for your project by running the following:
$ bazel run //:update_build_files
Build and test your project.
$ bazel test //...
- The
Package.resolved
file specifies that exact versions of the dependencies that were identified. - The
swift_deps_index.json
file contains information that is used by the Gazelle plugin and the respository rules. - The
swift_deps.bzl
file contains the repository rule declarations that are required to download and prepare the external Swift packages that are used by your workspace.