omp-py

omp-py embeds a statically linked, free-threaded CPython 3.14 interpreter in a Rust process. It freezes the Python standard library, repository-provided modules, and pinned pure-Python packages into the binary, while allowing native wheels to be loaded from a configured site-packages directory.

Structure

• src/lib.rs exposes Engine and Builder, installs the frozen-module tables, boots CPython in isolated mode, and provides the default site-packages location.
• build.rs links the vendored interpreter's native dependencies and packs project modules and bundled packages into frozen-module blobs without network access.
• python/ contains repository-provided Python modules, including omp_remote; requirements.txt pins bundled pure-Python packages.
• scripts/fetch-python.sh fetches the python-build-standalone archive and generates the derived build inputs (stdlib.bin, pyo3-config.txt, bundled packages); scripts/pack-pymodules.py and scripts/ld64.lld support the build.
• src/bin/demo.rs is the crate's omp-demo binary.
• THIRD-PARTY-NOTICES.txt records notices for bundled Python packages and is also exposed through THIRD_PARTY_LICENSES.

Philosophy

Keep the interpreter self-contained and deterministic: Python boots once per process in isolated mode, and frozen modules remain available to subinterpreters without relying on a host Python installation or ordinary filesystem imports. The frozen data is stored uncompressed so CPython can point directly into static binary data and the operating system can avoid paging unused modules.

Building

The crate links a vendored python-build-standalone CPython that is fetched once, outside cargo:

scripts/fetch-python.sh /path/to/vendor   # populates /path/to/vendor/python
export PYO3_CONFIG_FILE=/path/to/vendor/python/pyo3-config.txt
cargo build

PYO3_CONFIG_FILE must be set before cargo runs (environment or a .cargo/config.toml [env] entry) — it pins both pyo3 and this crate's build script to the same runtime. In this repository the checkout's .cargo/config.toml already points it at vendor/python/pyo3-config.txt.

The deliberate filesystem exception is site-packages, because native extension modules must be loaded from disk. Binaries supporting native wheels must export CPython's C API at final link time (for example, with -Wl,-export_dynamic); this crate applies the flag to its own binaries, while downstream binaries must apply the equivalent final-link configuration themselves.