Dockerfile to compile jiter to wheel for Pyodide/Pyscript

Dockerfile

# wasm32 compiler of jiter-python
# For PyScript 2024.10.1 - Required Python 3.12 and Emscripten 3.1.58
# USAGE: DOCKER_BUILDKIT=1 docker build --file Dockerfile --output out .

FROM python:3.12 AS builder

# Install pyodide-build
RUN pip install pyodide-build==0.26.3

# Install Latest Rust using rustup
RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --profile minimal
ENV PATH $PATH:/root/.cargo/bin

# Add Rust WASM target (Nightly version is required for wasm32-unknown-emscripten)
RUN rustup toolchain install nightly
RUN rustup target add --toolchain nightly wasm32-unknown-emscripten

# Install Emscripten
RUN git clone https://github.com/emscripten-core/emsdk.git
WORKDIR /emsdk
RUN ./emsdk install 3.1.58
RUN ./emsdk activate 3.1.58
# ./emsdk_env.sh (Fails when use emsdk_env.sh directly)
ENV PATH $PATH:/emsdk:/emsdk/upstream/emscripten:/emsdk/node/20.18.0_64bit/bin
ENV EMSDK /emsdk
ENV EMSDK_NODE /emsdk/node/20.18.0_64bit/bin/node
WORKDIR /

# Set environment variables for Emscripten
ENV PYO3_CROSS_PYTHON_VERSION 3.12
ENV PYO3_CROSS_LIB_DIR /usr/local/lib

# Get jiter
RUN git clone --depth 1 https://github.com/pydantic/jiter.git

# Build
WORKDIR /jiter/crates/jiter-python
RUN pyodide venv .venv-pyodide
RUN . .venv-pyodide/bin/activate \
    && RUSTUP_TOOLCHAIN=nightly pyodide build

# Export
FROM scratch AS export-stage
COPY --from=builder /jiter/crates/jiter-python/dist .

Explanation (in Japanese): https://qiita.com/narumichiaki/items/84d1e36f6b3180bdc642