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Dockerfile

@@ -1,30 +1,63 @@
-# Make sure it matches the Ruby version in .ruby-version and Gemfile
+# syntax = docker/dockerfile:1
-ARG RUBY_VERSION=3.2.0
+
-FROM ruby:$RUBY_VERSION
+# Make sure RUBY_VERSION matches the Ruby version in .ruby-version and Gemfile
+ARG RUBY_VERSION=3.2.2
+FROM registry.docker.com/library/ruby:$RUBY_VERSION-slim as base
 
 # Rails app lives here
 WORKDIR /rails
 
 # Set production environment
-ENV RAILS_LOG_TO_STDOUT="1" \
+ENV RAILS_ENV="production" \
-    RAILS_SERVE_STATIC_FILES="true" \
+    BUNDLE_DEPLOYMENT="1" \
-    RAILS_ENV="production" \
+    BUNDLE_PATH="/usr/local/bundle" \
-    BUNDLE_WITHOUT="development:test"
+    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 libvips pkg-config
 
 # Install application gems
 COPY Gemfile Gemfile.lock ./
-RUN bundle install
+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 --gemfile app/ lib/
+RUN bundle exec bootsnap precompile app/ lib/
 
 # Precompiling assets for production without requiring secret RAILS_MASTER_KEY
-RUN SECRET_KEY_BASE_DUMMY=1 bundle exec rails assets:precompile
+RUN SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile
 
-# Entrypoint prepares database and starts app on 0.0.0.0:3000 by default,
+
-# but can also take a rails command, like "console" or "runner" to start instead.
+# 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 libsqlite3-0 libvips && \
+    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"]