Rails docks upgrade interation 1

Author: igor-alexandrov

content/guides/ruby/containerize.md

@@ -18,19 +18,112 @@ aliases:
 
 ## Overview
 
-This section walks you through containerizing and running a Ruby on Rails application.
+This section walks you through containerizing and running a [Ruby on Rails](https://rubyonrails.org/) application.
 
-## Get the sample application
+Starting from Rails 7.1 [Docker is supported out of the box](https://guides.rubyonrails.org/7_1_release_notes.html#generate-dockerfiles-for-new-rails-applications). This means that you will get a `Dockerfile`, `.dockerignore` and `bin/docker-entrypoint` files generated for you when you create a new Rails application.
 
-The sample application uses the popular [Ruby on Rails](https://rubyonrails.org/) framework.
+If you have an existing Rails application, you will need to create the Docker assets manually. Unfortunately `docker init` command  does not yet support Rails. This means that if you are working with Rails, you'll need to copy Dockerfile and other related configurations manually from the examples below.
 
-Clone the sample application to use with this guide. Open a terminal, change directory to a directory that you want to work in, and run the following command to clone the repository:
+## Initialize Docker assets
 
-```console
-$ git clone https://github.com/falconcr/docker-ruby-on-rails.git
-```
+Rails 7.1 generates multistage Dockerfile out of the box, below is an example of such file generated from a Rails template.
 
-## Initialize Docker assets
+> Multistage Dockerfiles help create smaller, more efficient images by separating build and runtime dependencies, ensuring only necessary components are included in the final image. Read more about multi-stage builds [in a dedicated article](/get-started/docker-concepts/building-images/multi-stage-builds/)
+
+
+```dockerfile {collapse=true,title=Dockerfile}
+# syntax=docker/dockerfile:1
+# check=error=true
+
+# This Dockerfile is designed for production, not development.
+# docker build -t app .
+# docker run -d -p 80:80 -e RAILS_MASTER_KEY=<value from config/master.key> --name app app
+
+# For a containerized dev environment, see Dev Containers: https://guides.rubyonrails.org/getting_started_with_devcontainer.html
+
+# Make sure RUBY_VERSION matches the Ruby version in .ruby-version
+ARG RUBY_VERSION=3.3.6
+FROM docker.io/library/ruby:$RUBY_VERSION-slim AS base
+
+# Rails app lives here
+WORKDIR /rails
+
+# Install base packages
+# Replace sqlite3 with libpq-dev if using PostgreSQL, or libmysqlclient-dev if using MySQL
+RUN apt-get update -qq && \
+    apt-get install --no-install-recommends -y curl libjemalloc2 libvips sqlite3 && \
+    rm -rf /var/lib/apt/lists /var/cache/apt/archives
+
+# Set production environment
+ENV RAILS_ENV="production" \
+    BUNDLE_DEPLOYMENT="1" \
+    BUNDLE_PATH="/usr/local/bundle" \
+    BUNDLE_WITHOUT="development"
+
+# Throw-away build stage to reduce size of final image
+FROM base AS build
+
+# Install packages needed to build gems
+RUN apt-get update -qq && \
+    apt-get install --no-install-recommends -y build-essential curl git pkg-config && \
+    rm -rf /var/lib/apt/lists /var/cache/apt/archives
+
+# Install JavaScript dependencies and Node.js for asset compilation
+#
+# Uncomment the following lines if you are using NodeJS need to compile assets
+#
+# ARG NODE_VERSION=18.12.0
+# ARG YARN_VERSION=1.22.19
+# ENV PATH=/usr/local/node/bin:$PATH
+# RUN curl -sL https://github.com/nodenv/node-build/archive/master.tar.gz | tar xz -C /tmp/ && \
+#     /tmp/node-build-master/bin/node-build "${NODE_VERSION}" /usr/local/node && \
+#     npm install -g yarn@$YARN_VERSION && \
+#     npm install -g mjml && \
+#     rm -rf /tmp/node-build-master
+
+# Install application gems
+COPY Gemfile Gemfile.lock ./
+RUN bundle install && \
+    rm -rf ~/.bundle/ "${BUNDLE_PATH}"/ruby/*/cache "${BUNDLE_PATH}"/ruby/*/bundler/gems/*/.git && \
+    bundle exec bootsnap precompile --gemfile
+
+# Install node modules
+#
+# Uncomment the following lines if you are using NodeJS need to compile assets
+#
+# COPY package.json yarn.lock ./
+# RUN --mount=type=cache,id=yarn,target=/rails/.cache/yarn YARN_CACHE_FOLDER=/rails/.cache/yarn \
+#     yarn install --frozen-lockfile
+
+# Copy application code
+COPY . .
+
+# Precompile bootsnap code for faster boot times
+RUN bundle exec bootsnap precompile app/ lib/
+
+# Precompiling assets for production without requiring secret RAILS_MASTER_KEY
+RUN SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile
+
+# Final stage for app image
+FROM base
+
+# Copy built artifacts: gems, application
+COPY --from=build "${BUNDLE_PATH}" "${BUNDLE_PATH}"
+COPY --from=build /rails /rails
+
+# Run and own only the runtime files as a non-root user for security
+RUN groupadd --system --gid 1000 rails && \
+    useradd rails --uid 1000 --gid 1000 --create-home --shell /bin/bash && \
+    chown -R rails:rails db log storage tmp
+USER 1000:1000
+
+# Entrypoint prepares the database.
+ENTRYPOINT ["/rails/bin/docker-entrypoint"]
+
+# Start server via Thruster by default, this can be overwritten at runtime
+EXPOSE 80
+CMD ["./bin/thrust", "./bin/rails", "server"]
+```
 
 Now that you have an application, you can create the necessary Docker assets to
 containerize your application. You can use Docker Desktop's built-in Docker Init