Dockerfile

@@ -1,25 +1,36 @@
 # syntax = docker/dockerfile:1
 
-# Make sure RUBY_VERSION matches the Ruby version in .ruby-version and Gemfile
+# This Dockerfile is designed for production, not development. Use with Kamal or build'n'run by hand:
-ARG RUBY_VERSION=3.2.2
+# docker build -t my-app .
-FROM registry.docker.com/library/ruby:$RUBY_VERSION-slim as base
+# docker run -d -p 80:80 -p 443:443 --name my-app -e RAILS_MASTER_KEY=<value from config/master.key> my-app
+
+# For a containerized dev environment, see Dev Containers: https://guides.rubyonrails.org/getting_started_with_devcontainer.html
+
+# Make sure RUBY_VERSION matches the Ruby version in .ruby-version
+ARG RUBY_VERSION=3.3.1
+FROM docker.io/library/ruby:$RUBY_VERSION-slim AS base
 
 # Rails app lives here
 WORKDIR /rails
 
+# Install base packages
+RUN apt-get update -qq && \
+    apt-get install --no-install-recommends -y curl libjemalloc2 libsqlite3-0 libvips && \
+    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
+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
+    apt-get install --no-install-recommends -y build-essential git pkg-config && \
+    rm -rf /var/lib/apt/lists /var/cache/apt/archives
 
 # Install application gems
 COPY Gemfile Gemfile.lock ./
@@ -27,7 +38,6 @@ 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 . .
 
@@ -38,24 +48,20 @@ RUN bundle exec bootsnap precompile app/ lib/
 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 libsqlite3-0 libvips libjemalloc2 && \
-    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 "${BUNDLE_PATH}" "${BUNDLE_PATH}"
 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 && \
+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 rails:rails
+USER 1000:1000
-
-ENV LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libjemalloc.so.2
 
 # Entrypoint prepares the database.
 ENTRYPOINT ["/rails/bin/docker-entrypoint"]

Gemfile.lock

@@ -166,6 +166,8 @@ GEM
     net-smtp (0.5.0)
       net-protocol
     nio4r (2.7.3)
+    nokogiri (1.16.6-aarch64-linux)
+      racc (~> 1.4)
     nokogiri (1.16.6-arm64-darwin)
       racc (~> 1.4)
     nokogiri (1.16.6-x86_64-linux)
@@ -246,12 +248,15 @@ GEM
       actionpack (>= 6.1)
       activesupport (>= 6.1)
       sprockets (>= 3.0.0)
+    sqlite3 (2.0.2-aarch64-linux-gnu)
     sqlite3 (2.0.2-arm64-darwin)
     sqlite3 (2.0.2-x86_64-linux-gnu)
     stimulus-rails (1.3.3)
       railties (>= 6.0.0)
     stringio (3.1.1)
     strscan (3.1.0)
+    tailwindcss-rails (2.6.1-aarch64-linux)
+      railties (>= 7.0.0)
     tailwindcss-rails (2.6.1-arm64-darwin)
       railties (>= 7.0.0)
     tailwindcss-rails (2.6.1-x86_64-linux)
@@ -285,6 +290,7 @@ GEM
     zeitwerk (2.6.16)
 
 PLATFORMS
+  aarch64-linux
   arm64-darwin-23
   x86_64-linux
 

bin/docker-entrypoint

@@ -1,7 +1,12 @@
 #!/bin/bash -e
 
+# Enable jemalloc for reduced memory usage and latency.
+if [ -z "${LD_PRELOAD+x}" ] && [ -f /usr/lib/*/libjemalloc.so.2 ]; then
+  export LD_PRELOAD="$(echo /usr/lib/*/libjemalloc.so.2)"
+fi
+
 # If running the rails server then create or migrate existing database
-if [ "${*}" == "./bin/rails server" ]; then
+if [ "${1}" == "./bin/rails" ] && [ "${2}" == "server" ]; then
   ./bin/rails db:prepare
 fi