OpenPRoT

Technical Charter

The OpenPRoT Technical Charter can be found at https://github.com/OpenPRoT/.github/blob/main/GOVERNANCE.md

Getting Started

NOTE: We are converting our build system to bazel. We recommend installing bazelisk to automatically manage bazel versions.

Available Tasks

You can run tasks using the Pigweed workflow launcher pw or bazel.

• ./pw presubmit - Run presubmit checks: formatting, license checks, C/C++ header checks and clippy.
• ./pw format - Run the code formatters.
• bazel test //... - Run all tests.
• bazel build //docs - Build documentation.

Development

The project is structured as a bazel module.

Supply chain security

Release firmware is published with signed SLSA build provenance. See docs/src/supply-chain.md for how to verify it.

Requirements

• Bazel. We recommend installing bazelisk to automatically manage bazel versions.

No additional tools are required to build and test - all dependencies are managed by bazel. The sections below are optional and only describe editor setup.

VS Code setup

1. Install tools

• Rust toolchain and rust-analyzer. Builds do not use rustup, but the editor does. Install rustup. The repository's rust-toolchain.toml pins the nightly channel and lists the rust-analyzer, rust-src, rustfmt and clippy components, so rustup installs them automatically the first time rustc or cargo runs in the repository. To install them eagerly (or to add the component to an older checkout), run:

  rustup show                              # installs the pinned toolchain + components
  rustup component add rust-analyzer       # only if it is missing

• Buildifier formats BUILD.bazel/.bzl files. Download a prebuilt binary from the buildtools releases and put it on your PATH (use buildifier-linux-arm64 on ARM Linux, or buildifier-darwin-amd64 / buildifier-darwin-arm64 on macOS):

  sudo curl -fsSL -o /usr/local/bin/buildifier \
    https://github.com/bazelbuild/buildtools/releases/latest/download/buildifier-linux-amd64
  sudo chmod +x /usr/local/bin/buildifier
  buildifier --version

  Alternatively, go install github.com/bazelbuild/buildtools/buildifier@latest. ./pw format also runs buildifier, so the editor tool is only for format-on-save.

2. Install extensions

• Bazel (BazelBuild.vscode-bazel): Starlark syntax, target browsing, and buildifier integration.
• rust-analyzer (rust-lang.rust-analyzer).

3. Generate rust-project.json

There is no Cargo workspace, so rust-analyzer gets its crate graph from a generated rust-project.json (git-ignored) at the repository root:

bazel run @rules_rust//tools/rust_analyzer:gen_rust_project

This covers //..., which is large (hundreds of crates) and can use more than 10 GB of memory in rust-analyzer, which may get it killed on small machines or WSL. Prefer generating for only the targets you are working on:

bazel run @rules_rust//tools/rust_analyzer:gen_rust_project -- \
  //services/orchestrator/... //drivers/usart/...

Crates that only build for an embedded target (those with target_compatible_with = TARGET_COMPATIBLE_WITH, e.g. everything under target/ast10x0/) are skipped when generating for the host, so their files get no highlighting or hover. Pass the target's Bazel config to the generator's inner build with --config:

bazel run @rules_rust//tools/rust_analyzer:gen_rust_project -- \
  --config=virt_ast10x0 //target/ast10x0/peripherals:peripherals

The same applies to Earl Grey:

bazel run @rules_rust//tools/rust_analyzer:gen_rust_project -- \
  --config=k_earlgrey //target/earlgrey/...

Troubleshooting: rust-analyzer shows nothing for a file or a new target

If a file has no highlighting, hover or go-to-definition, its crate is most likely not in rust-project.json. Check, in order:

1. Is the target listed? Search rust-project.json for the crate name or file path. If it is missing, add the target (or a parent package such as //path/to/pkg/...) to the gen_rust_project command. Remember that each run overwrites the file.

2. Is it embedded-only? If the target uses target_compatible_with, it is skipped on the host platform, with no error. Pass the config that selects its platform after the --. The configs are defined in .bazelrc:

   Directory	Config
   target/ast10x0/	--config=virt_ast10x0
   target/earlgrey/	--config=k_earlgrey
   target/veer/	--config=k_veer

3. No config exists for your target? Add one to .bazelrc next to the existing ones. It must use the common: prefix, not just build:, so the setting also reaches the generator's inner build:

   common:k_mytarget --platforms=//target/mytarget:mytarget
   build:k_mytarget --build_tag_filters=-do_not_build,-kernel_doc_test
   

4. Reload. After regenerating, run "rust-analyzer: Reload Workspace". Double-check the spelling of the command and config names, since a typo in either fails the run.

Notes:

• Put --config after the --. Using --platforms on bazel run itself builds the generator for the embedded target and fails.
• Each run overwrites rust-project.json, so list every target you need in one command.
• Regenerate after adding crates or changing dependencies, then run "rust-analyzer: Reload Workspace".

4. Configure .vscode/settings.json

.vscode/settings.json is git-ignored, so each developer keeps their own copy. A suggested starting point:

{
    "rust-analyzer.linkedProjects": ["rust-project.json"],
    "rust-analyzer.cachePriming.enable": false,
    "rust-analyzer.numThreads": 4,
    "rust-analyzer.checkOnSave": false,
    "rust-analyzer.files.exclude": ["third_party/**", "bazel-*/**"],
    "bazel.buildifier.executable": "/usr/local/bin/buildifier",
    "bazel.codeLens.enable": true,
    "[starlark]": {
        "editor.defaultFormatter": "BazelBuild.vscode-bazel",
        "editor.formatOnSave": true
    }
}

• linkedProjects is required; it points rust-analyzer at the generated file.
• cachePriming.enable, numThreads, checkOnSave and files.exclude limit rust-analyzer's memory use; relax them if your machine has plenty of RAM.
• Set bazel.buildifierExecutable to the output of which buildifier.
• checkOnSave is disabled because the default cargo check does not work here. Use ./pw presubmit (which runs clippy through Bazel) instead.