IMAGE build
LAYER shared/alpine
LAYER shared/ruby

SCRIPT
    # Install Ruby runtime dependencies
    apk --no-cache add gdbm libressl readline zlib

    # Install Ruby build dependencies
    apk --no-cache add --virtual .deps build-base autoconf gdbm-dev libressl-dev linux-headers readline-dev zlib-dev

    # Download and unpack Ruby
    wget http://cache.ruby-lang.org/pub/ruby/2.3/ruby-2.3.6.tar.xz -O ruby.tar.xz
    mkdir -p /usr/src/ruby
    tar xJf ruby.tar.xz -C /usr/src/ruby --strip-components=1
    rm ruby.tar.xz
    cd /usr/src/ruby

    # Hackfix to suppress "Insecure world writable dir" warning
    sed -ni 'p;13a #define ENABLE_PATH_CHECK 0' file.c

    # Configure compilation + hackfix to detect isnan/isinf macros
    autoconf
    ac_cv_func_isnan=yes ac_cv_func_isinf=yes ./configure --build=x86_64-linux-musl --disable-install-doc --enable-shared

    # Compile and install Ruby
    make -j $(nproc)
    make install

    # Install RubyGems and Bundler
    mkdir -p /usr/local/etc
    echo -e 'install: --no-document\nupdate: --no-document' >/usr/local/etc/gemrc
    gem update --system

    # Cleanup
    cd /tmp
    rm -r /usr/src/ruby
    apk --no-cache del .deps
    rm -rf /root/.gem
RUN