Deployment¶

PyRust compiles each function the first time it runs, which needs Rust on that machine. For servers, Docker images and applications you ship to users, build the libraries ahead of time instead.

Build ahead of time¶

python -m pyrust_engine build mypackage/kernels.py

This compiles every function in the file that PyRust can compile, for the argument types in its annotations (unannotated parameters are int), into mypackage/__pyrust__/ with a manifest.json. Ship that folder with your package (for example as package data).

At run time PyRust looks for a matching library before compiling:

directories in the PYRUST_PREBUILT environment variable (separated by : on Linux/macOS, ; on Windows),
__pyrust__/ next to the module that defines the function.

A library is used only if it was built from the exact same generated code for the same platform (OS and CPU), and its SHA-256 matches the manifest. Anything else falls back to compiling (if Rust is available) or to plain Python.

Build once per platform you deploy to (for example in CI for linux-x86_64, darwin-arm64, win32-amd64) into the same folder: the manifest keeps entries for every platform.

Docker¶

FROM python:3.13-slim
RUN pip install "pyrust-engine[arrays]"
COPY mypackage/ /app/mypackage/          # includes mypackage/__pyrust__/ built for linux-x86_64

No Rust needed in the image.

Cache¶

Compiled libraries are cached in ~/.cache/pyrust_engine (override with PYRUST_CACHE_DIR). Entries not used for 30 days are removed automatically (PYRUST_CACHE_MAX_AGE_DAYS, 0 to disable). python -m pyrust_engine cache --days 7 --delete cleans up manually.