debian-ruby-jaemalloc-dockerfile

FROM buildpack-deps:stretch

# skip installing gem documentation
RUN mkdir -p /usr/local/etc \
        && { \
                echo 'install: --no-document'; \
                echo 'update: --no-document'; \
        } >> /usr/local/etc/gemrc

ENV RUBY_MAJOR 2.5
ENV RUBY_VERSION 2.5.1
ENV RUBY_DOWNLOAD_SHA256 886ac5eed41e3b5fc699be837b0087a6a5a3d10f464087560d2d21b3e71b754d
ENV RUBYGEMS_VERSION 2.7.7
ENV BUNDLER_VERSION 1.16.2

# some of ruby's build scripts are written in ruby
#   we purge system ruby later to make sure our final image uses what we just built
RUN set -ex \
        \
        && buildDeps=' \
                bison \
                dpkg-dev \
                libgdbm-dev \
                ruby \
        ' \
  && runtimeDeps=' \
      libjemalloc-dev \
  ' \
        && apt-get update \
        && apt-get install -y --no-install-recommends $buildDeps $runtimeDeps \
        && rm -rf /var/lib/apt/lists/* \
        \
        && wget -O ruby.tar.xz "https://cache.ruby-lang.org/pub/ruby/${RUBY_MAJOR%-rc}/ruby-$RUBY_VERSION.tar.xz" \
        && echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.xz" | sha256sum -c - \
        \
        && 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 \
        \
# hack in "ENABLE_PATH_CHECK" disabling to suppress:
#   warning: Insecure world writable dir
        && { \
                echo '#define ENABLE_PATH_CHECK 0'; \
                echo; \
                cat file.c; \
        } > file.c.new \
        && mv file.c.new file.c \
        \
        && autoconf \
        && gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" \
        && ./configure \
                --build="$gnuArch" \
                --disable-install-doc \
                --enable-shared \
    --with-jemalloc \
        && make -j "$(nproc)" \
        && make install \
        \
        && apt-get purge -y --auto-remove $buildDeps \
        && cd / \
        && rm -r /usr/src/ruby \
        \
        && gem update --system "$RUBYGEMS_VERSION" \
        && gem install bundler --version "$BUNDLER_VERSION" --force \
        && rm -r /root/.gem/

RUN ruby -r rbconfig -e "RbConfig::CONFIG['LIBS'].include?('jemalloc') ? puts('Ruby is compiled with jemalloc') : warn('JEMALLOC IS MISSING FROM RUBY')"

# install things globally, for great justice
# and don't create ".bundle" in all our apps
ENV GEM_HOME /usr/local/bundle
ENV BUNDLE_PATH="$GEM_HOME" \
        BUNDLE_SILENCE_ROOT_WARNING=1 \
        BUNDLE_APP_CONFIG="$GEM_HOME"
# path recommendation: https://github.com/bundler/bundler/pull/6469#issuecomment-383235438
ENV PATH $GEM_HOME/bin:$BUNDLE_PATH/gems/bin:$PATH
# adjust permissions of a few directories for running "gem install" as an arbitrary user
RUN mkdir -p "$GEM_HOME" && chmod 777 "$GEM_HOME"
# (BUNDLE_PATH = GEM_HOME, no need to mkdir/chown both)

CMD [ "irb" ]