Reloaded Rust Build C Library Workflow

This is a GitHub Action that can be used to build an optimized, lightweight binary (or C library) from a Rust project.

This action is used to build binaries with the following properties:

• Self-Built std: Reduces binary size and improves optimizations.
• Abort on Panic: Reduces binary size. Can be disabled if needed.
• Profile Guided Optimization (PGO): Improves performance by optimizing based on usage patterns.
• Cross-Compilation: Supports cross-compilation using cross-rs.
• Nightly Rust: Uses the nightly Rust toolchain for building and running.
• Tests and Coverage: Optionally run tests and generate coverage reports using the devops-rust-test-and-coverage action.

It can be used to build both binaries and C libraries.

Example Usage

As a single job/step of a workflow:

test-binary-build:
  strategy:
    matrix:
      include:
        - os: ubuntu-latest
          target: x86_64-unknown-linux-gnu
          use-pgo: true
          use-cross: false
        - os: ubuntu-latest
          target: i686-unknown-linux-gnu
          use-pgo: true
          use-cross: false
        - os: ubuntu-latest
          target: aarch64-unknown-linux-gnu
          use-pgo: false # no native runner
          use-cross: true
        - os: ubuntu-latest
          target: armv7-unknown-linux-gnueabihf
          use-pgo: false # no native runner
          use-cross: true
        - os: windows-latest
          target: x86_64-pc-windows-msvc
          use-pgo: true
          use-cross: false
        - os: windows-latest
          target: i686-pc-windows-msvc
          use-pgo: true
          use-cross: false
        - os: windows-latest
          target: aarch64-pc-windows-msvc
          use-pgo: false # no native runner
          use-cross: false
        - os: macos-13 # x86
          target: x86_64-apple-darwin
          use-pgo: true
          use-cross: false
        - os: macos-14 # M1
          target: aarch64-apple-darwin
          use-pgo: true
          use-cross: false
  runs-on: ${{ matrix.os }}
  steps:
    - name: Checkout Test Repository
      uses: actions/checkout@v4
      with:
        repository: Sewer56/prs-rs
        ref: d08599ed5473616f57d57a0966939e1a5dbda9b4
    - name: Test Binary Build
      uses: Reloaded-Project/devops-rust-lightweight-binary@v1
      with:
        target: ${{ matrix.target }}
        use-pgo: ${{ matrix.use-pgo }}
        use-cross: ${{ matrix.use-cross }}
        rust-project-path: "tools/cli/"
        crate-name: "prs-rs-cli"
        upload-artifacts: false
        run-tests-and-coverage: true

Setup

To use this action in your own repository:

1. Create a new workflow file (e.g., .github/workflows/build-c-library.yml) in your repository.
2. Copy the example usage job from above into the new workflow file.
3. Customize the input parameters as needed for your project.

Configuration

Inputs

Input	Required	Default	Description
rust-project-path	No	.	Path to the Rust project
pgo-project-path	No	.	Path to the Rust project used for gathering PGO data. Can be same or separate project.
crate-name	Yes		Name of the Rust crate (used to determine file name)
target	Yes		The target platform for the Rust compiler
features	No	''	Comma-separated list of features to include in the build
no-default-features	No	false	Do not include default features in the build
use-pgo	No	false	Use Profile-Guided Optimization [PGO] to build the library.
pgo-benchmark-name	No	'my_benchmark'	Benchmark name to use with PGO.
use-cross	No	false	Use cross-rs for building. If false, use cargo.
additional-rustflags	No	''	Additional RUSTFLAGS to pass to the Rust compiler
upload-artifacts	No	true	Upload the built artifacts as a GitHub Actions artifact
abort-on-panic	No	true	Abort immediately on panic. If false, the default panic handler is used.
build-library	No	false	Build a library instead of a binary.
run-tests-and-coverage	No	false	Run tests and coverage using the devops-rust-test-and-coverage action.
upload-coverage-to-codecov	No	true	Uploads coverage to codecov if run-tests-and-coverage is enabled.

Setting up Profile-Guided Optimization (PGO)

Profile-Guided Optimization works by compiling and executing a benchmark whose name and project can be defined by pgo-benchmark-name and pgo-project-path respectively. So you should strive to keep the benchmark as close to the final usage of your application as possible.

A benchmark for PGO can be defined as follows:

// Regular benchmarks, not PGO
#[cfg(not(feature = "pgo"))]
{
    bench_estimate(c);
    bench_decompress(c);
    bench_compress_file(c);
    bench_create_dict(c);
}

// Benchmark with realistic usage patterns for PGO.
#[cfg(feature = "pgo")]
{
    generate_pgo_data();
}

Then said profile is used to build the final version of your application.

For PGO to work, the target platform must be the same as the host that generated the profiling data. Sometimes you can get away with using cross to achieve this, for example:

# Host is x86-linux but this seems to work just a-ok!
target: aarch64-unknown-linux-gnu # x64 host to to aarch64 simulated guest
use-pgo: true
use-cross: true

If the process fails, your CI will fail, so do experiment.

Running Tests and Coverage

To run tests and generate coverage reports as part of the build process, set the run-tests-and-coverage input to true.

This will invoke the devops-rust-test-and-coverage action after the build step, using the same configuration as the build (e.g., target, features, use-cross, etc.).

The devops-rust-test-and-coverage action will run tests using either cargo or cross, depending on the use-cross input. If use-cross is false, it will also generate a coverage report using Tarpaulin and upload it to Codecov (if upload-coverage is true).

Note that code coverage is skipped when using cross due to incompatibility with Tarpaulin.

Building Libraries

To build a library instead of a binary, set the build-library input to true. This is equivalent to setting crate-type = ["cdylib", "staticlib"] in Cargo.toml.

When building a library, the generated artifacts will include static libraries (.a, .lib) and dynamic libraries (.so, .dll, .dylib) depending on the target platform.

Examples

Find more examples in the tests.

Custom PGO Project Path

- name: Build C Library
  uses: Reloaded-Project/devops-rust-lightweight-binary@v1
  with:
    rust-project-path: ./rust-project
    pgo-project-path: ./pgo-project
    crate-name: my-crate
    target: x86_64-unknown-linux-gnu

Using cross-rs for Building

- name: Build C Library
  uses: Reloaded-Project/devops-rust-lightweight-binary@v1
  with:
    crate-name: my-crate
    target: x86_64-unknown-linux-gnu
    use-cross: true

Custom Additional RUSTFLAGS

- name: Build C Library
  uses: Reloaded-Project/devops-rust-lightweight-binary@v1
  with:
    crate-name: my-crate
    target: x86_64-unknown-linux-gnu
    additional-rustflags: -C opt-level=3

Accessing the Built Artifacts

After a successful run, the built artifacts will be available as a downloadable artifact in the GitHub Actions run.

For binary builds, the artifact will be named ${{ inputs.crate-name }}-${{ inputs.target }}-${{ inputs.features }}.

For library builds, the artifact will be named C-Library-${{ inputs.target }}-${{ inputs.features }}.

To access the artifacts:

1. Navigate to the Actions tab in your repository.
2. Click on the workflow run that built the artifacts.
3. In the "Artifacts" section, you will find the generated artifacts, which you can download.

Why this Exists?

Building C libraries from Rust projects can be a complex process, especially when considering different target platforms, compiler flags, and optimizations like PGO.

This action simplifies the process by providing a configurable and reusable workflow that handles the building of C libraries from Rust projects.

Contributing

Contributions are welcome! If you encounter any issues or have suggestions for improvements, please open an issue or submit a pull request in this repository.

License

This project is licensed under the MIT License. See the LICENSE file for details.