Rails 7.1 generates Dockerfile by default - integrate it into our Dockerfile

[eoinkelly]

We already create a custom Dockerfile - we should compare it with our generated file and combine them in some sensible way.

[eoinkelly]

For reference, a vanilla rails new myapp with 7.1.1 generates the following docker related files

Dockerfile

# syntax = docker/dockerfile:1

# Make sure RUBY_VERSION matches the Ruby version in .ruby-version and Gemfile
ARG RUBY_VERSION=3.2.2
FROM registry.docker.com/library/ruby:$RUBY_VERSION-slim as base

# Rails app lives here
WORKDIR /rails

# 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 git libpq-dev libvips pkg-config

# 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

# 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

# Install packages needed for deployment
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y curl libvips postgresql-client && \
    rm -rf /var/lib/apt/lists /var/cache/apt/archives

# Copy built artifacts: gems, application
COPY --from=build /usr/local/bundle /usr/local/bundle
COPY --from=build /rails /rails

# Run and own only the runtime files as a non-root user for security
RUN useradd rails --create-home --shell /bin/bash && \
    chown -R rails:rails db log storage tmp
USER rails:rails

# Entrypoint prepares the database.
ENTRYPOINT ["/rails/bin/docker-entrypoint"]

# Start the server by default, this can be overwritten at runtime
EXPOSE 3000
CMD ["./bin/rails", "server"]

./bin/docker-entrypoint

#!/bin/bash -e

# If running the rails server then create or migrate existing database
if [ "${1}" == "./bin/rails" ] && [ "${2}" == "server" ]; then
  ./bin/rails db:prepare
fi

exec "${@}"

./dockerignore

# See https://docs.docker.com/engine/reference/builder/#dockerignore-file for more about ignoring files.

# Ignore git directory.
/.git/

# Ignore bundler config.
/.bundle

# Ignore all environment files (except templates).
/.env*
!/.env*.erb

# Ignore all default key files.
/config/master.key
/config/credentials/*.key

# Ignore all logfiles and tempfiles.
/log/*
/tmp/*
!/log/.keep
!/tmp/.keep

# Ignore pidfiles, but keep the directory.
/tmp/pids/*
!/tmp/pids/.keep

# Ignore storage (uploaded files in development and any SQLite databases).
/storage/*
!/storage/.keep
/tmp/storage/*
!/tmp/storage/.keep

# Ignore assets.
/node_modules/
/app/assets/builds/*
!/app/assets/builds/.keep
/public/assets