Cxx-Buck2-vcpkg-Examples

A C++ example repository using Buck 2 with vcpkg (the C++ package manager) and scripts to generate a compile-commands.json.

• Dependencies
• Using this Example
  • Available Targets
  • Buck 2 Files
• Converting an Existing or Generating a new C++ Project with Buck 2
• Other Buck 2 C++ Examples
• Buck 2 Examples for other Languages
• Contributions
• License

Dependencies

You need the following:

• Buck 2: Buck2 Official Website
• Python 3, Python 3.8 or newer.
• on MacOS ICU needs the Homebrew packages autoconf, automake and autoconf-archive (the last one you may not have installed yet). To install, run brew install autoconf automake autoconf-archive.

Install Buck 2 like documented at Buck 2 - Getting Started.

Using this Example

• Checkout the Buck 2 prelude containing the language rules: git submodule update --init
• Download all vcpkg packages defined in ./third-party/vcpkg.json: buck2 build :vcpkg-install
• Now you should be able to build and run the example binary: buck2 run //app:app.
• To generate a compile_commands.json file (needed for the C++ LSPs), run buck2 build //:compile_commands.

Available Targets

• buck2 clean - Deletes all generated files.

• buck2 targets //... - Lists all available targets, including all configured vcpkg packages.

• buck2 build :vcpkg-install - A alias for buck2 build //buck2_vcpkg:vcpkg_install to install all packages configured in ./third-party/vcpkg.json. The libraries and header files have to be added to ./third-party/BUCK to use them in the source.

• buck2 build :exe - A alias for buck2 build //app:app, builds the executable ./app/main.cpp. Buck 2 configuration ./app/BUCK

• buck2 run :exe - A alias for buck2 run //app:app, builds and runs the executable ./app/main.cpp. Buck 2 configuration ./app/BUCK

• buck2 build :test - A alias for buck2 build //test:test, builds the tests in ./test/test_main.cpp. Buck 2 configuration ./test/BUCK.

• buck2 test :test - A alias for buck2 test //test:test, builds and runs the tests in ./test/test_main.cpp. Buck 2 configuration ./test/BUCK.

• buck2 run :test - A alias for buck2 run //test:test, builds and runs the tests in ./test/test_main.cpp. Buck 2 configuration ./test/BUCK. The difference to buck2 test is mostly in the output, run uses for example colored output.

• buck2 build :lib - A alias for buck2 build //lib:library, builds the library in ./lib/lib.cpp. Buck 2 configuration ./lib/BUCK

• buck2 build :compile_commands - Generates the file ./compile_commands.json, needed for LSPs. The actual python scripts and Buck 2 configuration is located in ./concat_compile_cmds/, the list of targets to add to ./compile_commands.json is located in the Buck 2 configuration file ./BUCK:

  concat_compile_cmds(
    name="compile_commands",
    files=[
        "//app:app[full-compilation-database]",
        "//lib:library[full-compilation-database]",
        "//test:test[full-compilation-database]",
    ],
  )

Buck 2 Files

• ./.buckroot - A empty file to mark the Buck 2 root. The root directory of all Buck 2 projects, not just a single one. Generated by buck2 init.

• ./.buckconfig - The general Buck 2 configuration. Generated by buck2 init. Set the execution platform to the default one of the prelude.

  [build]
  execution_platforms = prelude//platforms:default

• ./BUCK - Main Buck 2 configuration, holds the aliases, the vcpkg rules and the configuration for the generation of ./compile_commands.json. You have to manually edit this.

• ./toolchains/BUCK - Configuration of the Buck 2 toolchains - Python and C++. You have to manually edit this.

• ./concat_compile_cmds/ - Python script and Buck2 configuration to generate the file ./compile_commands.json. Just copy that in your own project.

• ./buck2_vcpkg/ - Configuration of the vcpkg installer. In ./buck2_vcpkg/BUCK you have to configure the Git revision of vcpkg to use and the triplet describing your architecture and OS.

• ./third-party/BUCK - You need to create this to be able to use the installed vcpkg packages.

• ./lib/BUCK - The library's configuration. You have to manually create that.

• ./app/BUCK - Configuration of the executable. You have to manually create that.

• ./test/BUCK - Test configuration. You have to manually create that.

Converting an Existing or Generating a new C++ Project with Buck 2

1. Initialize the project by running buck2 init --git
2. Set the execution platform in ./.buckconfig to the default one of the prelude.

[build]
execution_platforms = prelude//platforms:default

3. Generate a ./third-party/vcpkg.json containing your dependencies.
4. Edit the files ./toolchains/BUCK and ./BUCK to include the C++ and Python toolchains.
5. Add sources and BUCK files. Like ./lib/BUCK, ./app/BUCK and ./test/BUCK.
6. Copy the directory ./concat_compile_cmds/ to your project and configure it in ./toolchains/BUCK and ./BUCK to be able to generate a ./compile_commands.json file in your root directory.
7. Copy the directory ./buck2_vcpkg/ into your project and configure it in ./buck2_vcpkg/BUCK and the libraries and headers to use in ./third-party/BUCK.
8. Run buck2 build :compile_commands to generate the file ./compile_commands.json for use with your LSP (like clangd).

Other Buck 2 C++ Examples

• My Examples using Conan as package manager: Cxx-Buck2-Conan-Examples
• The official examples: Facebook: Buck 2 C++ Examples
• The official Conan examples: Facebook: Buck 2 C++ Conan Examples
• Rust and C++ interop examples Interop Between C++ and Rust

Buck 2 Examples for other Languages

I've also made examples for OCaml: OCaml-Buck-2-Examples.

Contributions

If you want to add tips or tricks on using Buck 2, examples, a link to other examples, blog or forum posts, or found an error, please open an issue or pull request with your changes.

License

These Examples are licensed under the MIT. See ./LICENSE for details.