Too many versions of Ruby in my app - which one are really necessary?-CodePudding

I have a ruby on rails 7 app so I have ruby listed in my gemfile.

app/Gemfile

source "https://rubygems.org"
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby "~> 3.1"

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem "rails", "~> 7.0.0"

But beyond the "standard" Rails app, i'm leveraging a Dockerfile with docker-compose to build a docker container as I'm using Github Codespace. I'm pretty beginner with docker so i more or less used the boilerplate provided by microsoft which starts like this:

# # [Choice] Ruby version (use -bullseye variants on local arm64/Apple Silicon): 3, 3.1, 3.0, 2, 2.7, 2.6, 3-bullseye, 3.1-bullseye, 3.0-bullseye, 2-bullseye, 2.7-bullseye, 2.6-bullseye, 3-buster, 3.1-buster, 3.0-buster, 2-buster, 2.7-buster, 2.6-buster
ARG VARIANT=3.1-bullseye
# Note the images provided by Microsoft have some pre-installed packages
# to make them work out of the box for dev container feature
FROM mcr.microsoft.com/vscode/devcontainers/ruby:0-${VARIANT}

But then I added also to manage versions of ruby and other libraries a Version manager called ASDF so a bit futher down on the same dockerfile, it reads:

# # Environment variables
ARG RUBY_VERSION latest

RUN git clone --depth 1 https://github.com/asdf-vm/asdf.git $HOME/.asdf && \
    echo '. $HOME/.asdf/asdf.sh' >> $HOME/.bashrc && \
    echo '. $HOME/.asdf/completions/asdf.bash' >> $HOME/.bashrc && \
    echo '. $HOME/.asdf/asdf.sh' >> $HOME/.profile
# ASDF steps: install asdf ruby plugin, then a ruby version, then set our machine e.g our container's global Ruby version
RUN bash -c "source $HOME/.bashrc  && 
    asdf plugin add ruby https://github.com/asdf-vm/asdf-ruby.git &&
    asdf install ruby $RUBY_VERSION &&
    asdf global ruby $RUBY_VERSION"

So in total that's like 3 places where I think there is Ruby that gets installed. I feel it's too much and not really a good practice. Should I remove ruby from my gemfile and at the toip to only keep ASDF ruby as this is the tool i manage ruby versions with?

Should I keep two of them? What is recommended?

CodePudding user response：

You usually should not use a version manager with Docker (asdf, rbenv, rvm, ...). At a mechanical level, most paths to running a Docker container don't read the .bashrc or .profile files you set up, and you need a pretty roundabout path to "activate" the version manager. Style-wise, the Docker image contains only a single application and its runtime, so you'll only ever need a single Ruby version within the context of its container, and the image's FROM line is enough.

You should keep the ruby constraint in your Gemfile, which helps ensure you have a compatible version of Ruby in other environments (for example, using asdf in your non-Docker desktop setup). And you need a Ruby version in your image's FROM line so Docker knows which base image to use.

In your example, without installing or invoking asdf, the base image already has Ruby 3.1 available, so you don't need to do any additional work to (re)install it.