Dockerfile

FROM phusion/baseimage:0.9.18

RUN apt-get update && \
    apt-get install -y zlib1g-dev libssl-dev

#
# ruby
#

# 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 2.4
ENV RUBY_VERSION 2.4.2
ENV RUBY_DOWNLOAD_SHA256 93b9e75e00b262bc4def6b26b7ae8717efc252c47154abb7392e54357e6c8c9c
ENV RUBYGEMS_VERSION 2.7.2

# some of ruby's build scripts are written in ruby
# we purge this later to make sure our final image uses what we just built
RUN set -ex \
	&& buildDeps=' \
		bison \
		libgdbm-dev \
		build-essential \
		autoconf \
		ruby \
	' \
	&& apt-get update \
	&& apt-get install -y --no-install-recommends $buildDeps \
	&& rm -rf /var/lib/apt/lists/* \
	&& curl -fSL -o ruby.tar.gz "http://cache.ruby-lang.org/pub/ruby/$RUBY_MAJOR/ruby-$RUBY_VERSION.tar.gz" \
	&& echo "$RUBY_DOWNLOAD_SHA256 *ruby.tar.gz" | sha256sum -c - \
	&& mkdir -p /usr/src/ruby \
	&& tar -xzf ruby.tar.gz -C /usr/src/ruby --strip-components=1 \
	&& rm ruby.tar.gz \
	&& cd /usr/src/ruby \
	&& { echo '#define ENABLE_PATH_CHECK 0'; echo; cat file.c; } > file.c.new && mv file.c.new file.c \
	&& autoconf \
	&& ./configure --disable-install-doc \
	&& make -j"$(nproc)" \
	&& make install \
	&& apt-get purge -y --auto-remove $buildDeps \
	&& gem update --system $RUBYGEMS_VERSION \
	&& rm -r /usr/src/ruby

ENV BUNDLER_VERSION 1.13

RUN rm /usr/local/bin/bundle && gem install bundler --version "$BUNDLER_VERSION"

# install things globally, for great justice
# and don't create ".bundle" in all our apps
ENV GEM_HOME /usr/local/bundle
ENV BUNDLE_PATH="$GEM_HOME" \
	BUNDLE_BIN="$GEM_HOME/bin" \
	BUNDLE_SILENCE_ROOT_WARNING=1 \
	BUNDLE_APP_CONFIG="$GEM_HOME"
ENV PATH $BUNDLE_BIN:$PATH
RUN mkdir -p "$GEM_HOME" "$BUNDLE_BIN" \
	&& chmod 777 "$GEM_HOME" "$BUNDLE_BIN"