Dockerfile

ARG BASE=ghcr.io/r-wasm/flang-wasm:main
FROM $BASE as webr

# Setup environment for Emscripten
ENV PATH="/opt/emsdk:/opt/emsdk/upstream/emscripten:${PATH}"
ENV EMSDK="/opt/emsdk"
ENV WEBR_ROOT="/opt/webr"
ENV EM_NODE_JS="/usr/bin/node"
ENV EMFC="/opt/flang/host/bin/flang-new"

# Step 1: Build fake Rust DEB packages
# 
# Installing this makes sure the toolchain installed in the later step is used
# instead of the one that the distro (Ubuntu) provides.
FROM webr as deb_build
RUN mkdir /opt/fake_rust/ && \
    apt-get update && \
    apt-get install -y equivs lsb-release &&\
    equivs-control fake_rust && \
    sed -i 's/Package:.*/Package: rustc/' fake_rust && \
    sed -i 's/# Version:.*/Version: 99.0/' fake_rust && \
    equivs-build fake_rust && \
    sed -i 's/Package:.*/Package: cargo/' fake_rust && \
    equivs-build fake_rust && \
    mv rustc_99.0_all.deb cargo_99.0_all.deb /opt/fake_rust/

# Step 2: Do the necessary setups
FROM webr as scratch
# Install node 18
RUN mkdir -p /etc/apt/keyrings && \
    curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | \
    gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg && \
    echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] \
    https://deb.nodesource.com/node_18.x nodistro main" | \
    tee /etc/apt/sources.list.d/nodesource.list && \
    apt-get update && \
    apt-get install nodejs -y

# Install Rust; these lines are based on the official Rust docker image:
# https://github.com/rust-lang/docker-rust/blob/master/Dockerfile-debian.template
ENV PATH="/usr/local/cargo/bin:${PATH}"
ENV RUSTUP_HOME=/usr/local/rustup
ENV CARGO_HOME=/usr/local/cargo
RUN set -eux; \
    wget "https://static.rust-lang.org/rustup/archive/1.26.0/x86_64-unknown-linux-gnu/rustup-init"; \
    echo "0b2f6c8f85a3d02fde2efc0ced4657869d73fccfce59defb4e8d29233116e6db *rustup-init" | sha256sum -c -; \
    chmod +x rustup-init; \
    ./rustup-init -y \
    --no-modify-path \
    --profile minimal \
    --default-toolchain nightly \
    --default-host x86_64-unknown-linux-gnu \
    --target wasm32-unknown-emscripten \
    --component rust-src; \
    rm rustup-init; \
    chmod -R a+w $RUSTUP_HOME $CARGO_HOME; \
    rustup --version; \
    cargo --version; \
    rustc --version;

# Install the fake Rust DEB packages. 
COPY --from=deb_build /opt/fake_rust /tmp/fake_rust
RUN dpkg -i /tmp/fake_rust/rustc_99.0_all.deb && \
    dpkg -i /tmp/fake_rust/cargo_99.0_all.deb && \
    rm -rf /tmp/fake_rust

# Install rig
RUN curl -L https://rig.r-pkg.org/deb/rig.gpg -o /etc/apt/trusted.gpg.d/rig.gpg && \
    echo "deb http://rig.r-pkg.org/deb rig main" > /etc/apt/sources.list.d/rig.list && \
    apt-get update && \
    apt-get install r-rig -y

# Because $HOME gets masked by GHA with the host $HOME
ENV R_LIBS_USER=/opt/R/current/lib/R/site-library
RUN rig add 4.3.2

# Download webR and configure for LLVM flang
RUN git clone https://github.com/r-wasm/webr.git /opt/webr
WORKDIR /opt/webr
ARG WEBRCI_SHA=HEAD
RUN git checkout ${WEBRCI_SHA}
RUN ./configure

# Install r-wasm's webr package for native R
RUN R CMD INSTALL packages/webr

# Build webR with supporting Wasm libs
RUN cd libs && make all
RUN make

# Cleanup
RUN apt-get clean && rm -rf /var/lib/apt/lists/*
RUN rm -rf /tmp/rig
RUN rm -rf libs/download libs/build src/node_modules R/download
RUN cd src && make clean

# Step 3: Squash docker image layers
FROM webr
COPY --from=scratch / /
ENV PATH="/usr/local/cargo/bin:${PATH}"
ENV RUSTUP_HOME=/usr/local/rustup
ENV CARGO_HOME=/usr/local/cargo
WORKDIR /root
SHELL ["/bin/bash", "-c"]