Creating Docker with Ruby and R - r

Question

I have a rails application that combines some R code. It works fine, and now is the time to dockerize it. I tried creating the docker based on a ruby image, which failed installing R properly, and then the other way around (R image, installing ruby using rbenv as explained here) which failed too.
Has anyone experienced with this combo?
EDIT: I have managed to create a docker using the R image, however this requires a tiring installation of many ruby dependencies. So consider this side done.
Still, why won't the other way (installing R on ruby image) work?
Ruby-based:
FROM ruby:2.7.1 AS rails-toolbox
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
RUN mkdir /app
WORKDIR /app
ADD shalev/Gemfile /app/Gemfile
ADD shalev/Gemfile.lock /app/Gemfile.lock
RUN bundle install --without development test doc --jobs=4
RUN apt-get install -y apt-utils
RUN apt-get install -y apt-transport-https
RUN wget -qO- https://cloud.r-project.org/bin/linux/ubuntu/marutter_pubkey.asc | tee -a /etc/apt/trusted.gpg.d/cran_ubuntu_key.asc
RUN echo "deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/" | tee -a /etc/apt/sources.list
RUN apt-get update
RUN apt-get install r-base
COPY shalev/ /app/
[...]
error message:
Step 13/20 : RUN apt-get install r-base
---> Running in f546cfe57d33
Reading package lists...
Building dependency tree...
Reading state information...
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
r-base : Depends: r-base-core (>= 3.6.3-1bionic) but it is not going to be installed
Depends: r-recommended (= 3.6.3-1bionic) but it is not going to be installed
Recommends: r-base-html but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
The command '/bin/sh -c apt-get install r-base' returned a non-zero code: 100
R-based:
FROM rocker/r-ver:3.6.3
RUN apt-get update -qq && apt-get install -y apt-utils apt-transport-https build-essential libpq-dev nodejs
RUN apt-get install -y git-core zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev software-properties-common libffi-dev nodejs yarn curl bzip2
RUN git clone https://github.com/rbenv/rbenv.git ~/.rbenv \
&& echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc \
&& echo 'eval "$(rbenv init -)"' >> ~/.bashrc
ENV HOME /home/shalev
ENV PATH "$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"
ENV RUBY_VERSION 2.7.1
RUN mkdir -p "$(rbenv root)"/plugins \
&& git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build
RUN rbenv install $RUBY_VERSION
RUN rbenv global $RUBY_VERSION && rbenv versions && ruby -v
RUN mkdir /app
[...]
error message:
Step 9/25 : RUN rbenv install $RUBY_VERSION
---> Running in 9939299d6ed1
/bin/sh: 1: rbenv: not found

Answer 1

You can use the stand alone version of ruby-build.
Note that you are root and not shalev inside the container:
FROM rocker/r-ver:3.6.3
RUN apt-get update -qq && \
apt-get install -y \
apt-utils apt-transport-https \
build-essential libpq-dev nodejs
RUN apt-get install -y \
git-core zlib1g-dev build-essential \
libssl-dev libreadline-dev libyaml-dev \
libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev \
libcurl4-openssl-dev software-properties-common \
libffi-dev nodejs yarn curl bzip2
RUN git clone https://github.com/rbenv/rbenv.git ~/.rbenv \
&& echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc \
&& echo 'eval "$(rbenv init -)"' >> ~/.bashrc
ENV PATH "/root/.rbenv/bin/:/root/.rbenv/shims/:$PATH"
ENV RUBY_VERSION 2.7.1
RUN git clone https://github.com/rbenv/ruby-build.git && \
PREFIX=/usr/local ./ruby-build/install.sh
RUN rbenv install $RUBY_VERSION && \
rbenv global $RUBY_VERSION && \
rbenv versions
RUN mkdir /app

Answer 2

I managed to make it work with the ruby image as well:
FROM ruby:2.7.1 AS rails-toolbox
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
RUN apt-get install -y apt-utils apt-transport-https
RUN apt-get install -y gfortran
RUN wget -c https://cran.r-project.org/src/base/R-3/R-3.6.3.tar.gz
RUN tar -xf R-3.6.3.tar.gz
WORKDIR "/R-3.6.3"
RUN ./configure
RUN make -j9
RUN make install
WORKDIR "/root"
RUN mkdir /app
[...]