Move production to the default and devlopment to alternate

.github/workflows/docker.yml

@@ -26,7 +26,7 @@ jobs:
         uses: docker/build-push-action@v5
         with:
           context: .
-          file: ./production.Dockerfile
+          file: ./Dockerfile
           push: false
           load: true
           tags: ${{ env.TEST_TAG }}

Dockerfile

@@ -4,7 +4,22 @@
 ARG RUBY_VERSION=3.2.2
 FROM registry.docker.com/library/ruby:$RUBY_VERSION-slim as base
 
-# OS Level Dependencies
+WORKDIR /rails
+
+# Set production environment
+ENV RAILS_ENV="production" \
+    BUNDLE_DEPLOYMENT="1" \
+    BUNDLE_JOBS="4" \
+    BUNDLE_WITHOUT="development:test" \
+    BUNDLE_PATH="/usr/local/bundle"
+
+
+# Throw-away build stage to reduce size of final image
+FROM base as build
+
+# Install packages needed to build gems
+# NOTE: This example project intentionally does not require or install node.js
+
 RUN --mount=type=cache,target=/var/cache/apt \
   --mount=type=cache,target=/var/lib/apt,sharing=locked \
   --mount=type=tmpfs,target=/var/log \
@@ -17,20 +32,55 @@ RUN --mount=type=cache,target=/var/cache/apt \
     less \
     git \
     libpq-dev \
-    postgresql-client \
     libvips \
-    curl
+    pkg-config
 
-ENV LANG=C.UTF-8 \
-  BUNDLE_JOBS=4 \
-  BUNDLE_RETRY=3
-
-RUN gem update --system && gem install bundler
+# 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
 
-WORKDIR /usr/src/app
+# Copy application code
+COPY . .
 
-ENTRYPOINT ["./bin/docker-entrypoint"]
+# Precompile bootsnap code for faster boot times
+RUN bundle exec bootsnap precompile app/ lib/
 
-EXPOSE 3000
+# Precompiling assets for production without requiring secret RAILS_MASTER_KEY
+RUN SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile
 
-CMD ["bundle", "exec", "rails", "s", "-b", "0.0.0.0"]
+
+# Final stage for app image
+FROM base
+
+# Install packages needed for deployment
+RUN --mount=type=cache,target=/var/cache/apt \
+  --mount=type=cache,target=/var/lib/apt,sharing=locked \
+  --mount=type=tmpfs,target=/var/log \
+  rm -f /etc/apt/apt.conf.d/docker-clean; \
+  echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' > /etc/apt/apt.conf.d/keep-cache; \
+  apt-get update -qq \
+  && apt-get install -yq --no-install-recommends \
+  curl \
+  postgresql-client \
+  libvips
+
+# 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-production"]
+
+HEALTHCHECK --interval=15s --timeout=3s --start-period=0s --start-interval=5s --retries=3 \
+  CMD curl -f http://localhost:3000/up || exit 1
+
+# Start the server by default, this can be overwritten at runtime
+EXPOSE 3000
+CMD ["bundle", "exec", "puma", "-C", "config/puma.rb"]

README.md

@@ -75,7 +75,7 @@ docker compose up --build
 
 ### with [BuildKit](https://docs.docker.com/build/buildkit/)
 ```
-DOCKER_BUILDKIT=1 docker build --tag rails-on-docker --file production.Dockerfile . --load
+DOCKER_BUILDKIT=1 docker build --tag rails-on-docker --load .
 ```
 
 Test the image can be used and Rails starts up, use a fake key for testing purposes only:

bin/docker-entrypoint

@@ -1,11 +1,17 @@
-#!/bin/bash
-set -e
+#!/bin/bash -e
 
-# Remove a potentially pre-existing server.pid for Rails.
-rm -f /usr/src/app/tmp/pids/server.pid
+echo "entrypoint"
+echo "${*}"
 
-echo "bundle install..."
-bundle check || bundle install --jobs 4
+# NOTE: Enable this as you need to get migrations working in your deployed
+# (i.e. Production) environments. Match the condition check to what you have in
+# the Dockerfile CMD. I use puma in the production.Dockerfile as that's the
+# recommended option by the Puma team (https://github.com/puma/puma#rails), but
+# the default Rails Dockerfile uses `./bin/rails server`
+#
+# If running the rails server then create or migrate existing database
+# if [ "${*}" == "./bin/rails server" ]; then
+#   ./bin/rails db:prepare
+# fi
 
-# Then exec the container's main process (what's set as CMD in the Dockerfile).
-exec "$@"
+exec "${@}"

bin/docker-entrypoint-development

@@ -0,0 +1,11 @@
+#!/bin/bash
+set -e
+
+# Remove a potentially pre-existing server.pid for Rails.
+rm -f /usr/src/app/tmp/pids/server.pid
+
+echo "bundle install..."
+bundle check || bundle install --jobs 4
+
+# Then exec the container's main process (what's set as CMD in the Dockerfile).
+exec "$@"

compose.yaml

@@ -1,6 +1,8 @@
 services:
   web:
-    build: .
+    build:
+      context: ./
+      dockerfile: development.Dockerfile
     command: bash -c "rm -f tmp/pids/server.pid && bin/rails s -p 3000 -b '0.0.0.0'"
     volumes:
       - .:/usr/src/app

development.Dockerfile

@@ -0,0 +1,36 @@
+# 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
+
+# OS Level Dependencies
+RUN --mount=type=cache,target=/var/cache/apt \
+  --mount=type=cache,target=/var/lib/apt,sharing=locked \
+  --mount=type=tmpfs,target=/var/log \
+  rm -f /etc/apt/apt.conf.d/docker-clean; \
+  echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' > /etc/apt/apt.conf.d/keep-cache; \
+  apt-get update -qq \
+  && apt-get install -yq --no-install-recommends \
+    build-essential \
+    gnupg2 \
+    less \
+    git \
+    libpq-dev \
+    postgresql-client \
+    libvips \
+    curl
+
+ENV LANG=C.UTF-8 \
+  BUNDLE_JOBS=4 \
+  BUNDLE_RETRY=3
+
+RUN gem update --system && gem install bundler
+
+WORKDIR /usr/src/app
+
+ENTRYPOINT ["./bin/docker-entrypoint-development"]
+
+EXPOSE 3000
+
+CMD ["bundle", "exec", "rails", "s", "-b", "0.0.0.0"]