[Installing node / npm in a Ruby Docker image]

Dockerfile

# STAGE 1: Initial setup
FROM ruby:2.6.10 as base
WORKDIR /app

# Use a bundler version that works for both this version of Ruby and (if applicable) the version of Rails being used
# NOTE: The RubyGems version that comes with Ruby 2.6 contains a bug and must be updated to v3.2.3.

# Use a bundler version that works for both this version of Ruby and (if applicable) the version of Rails being used
# NOTE: Bundler v2.4.22 is the last version that works with Ruby 2.6.
#       RubyGems v3.4.22 is the last version that works with Ruby 2.6.
#       When Ruby gets upgraded, the version flags can be updated below.
ENV BUNDLER_VERSION=2.4.22
ARG RUBYGEMS_VERSION=3.2.3

# NOTE: Pinning solargraph version for now because there is a bug with 0.50.0
ARG SOLARGRAPH_VERSION=0.49.0

# Latest gem versions available for Ruby 2.6 as of 2024-09-30
ARG DEBUG_VERSION=1.8.0
ARG PYGMENTS_VERSION=3.0.0
ARG RUBOCOP_VERSION=1.50.2
ARG SOLARGRAPH_RAILS_VERSION=1.1.0

# Get NodeJS
COPY --from=node:20-slim /usr/local/bin /usr/local/bin

# Get npm
COPY --from=node:20-slim /usr/local/lib/node_modules /usr/local/lib/node_modules

# Install missing package(s)
RUN apt-get update -qq && apt-get install -yq --no-install-recommends \
    wait-for-it=0.0~git20180723-1 \
    && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

# Prep for gem installation & install gems used for IntelliSense and debugging
RUN gem update --system ${RUBYGEMS_VERSION} \
    && gem install bundler:${BUNDLER_VERSION} \
    && gem install pygments.rb:${PYGMENTS_VERSION} \
                   debug:${DEBUG_VERSION} \
                   rubocop:${RUBOCOP_VERSION} \
                   solargraph:${SOLARGRAPH_VERSION} \
                   solargraph-rails:${SOLARGRAPH_RAILS_VERSION}

# Keep container running
CMD ["tail", "-f", "/dev/null"]