Dockerfile

# syntax=docker/dockerfile:1
# check=error=true

# Match Ruby version from .tool-versions
ARG RUBY_VERSION=3.3.8
FROM ruby:$RUBY_VERSION-slim AS base

WORKDIR /rails

# Install base packages
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y \
      curl \
      libjemalloc2 \
      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:test"


# Build stage
FROM base AS build

# Install packages needed to build gems
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y \
      build-essential \
      libffi-dev \
      libyaml-dev \
      libsqlite3-dev \
      git && \
    rm -rf /var/lib/apt/lists /var/cache/apt/archives

# Install 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/

# Precompile assets for production
RUN SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile


# Final production image
FROM base

# Copy built artifacts: gems, application
COPY --from=build "${BUNDLE_PATH}" "${BUNDLE_PATH}"
COPY --from=build /rails /rails

# Run as non-root user
RUN groupadd --system --gid 1000 rails && \
    useradd rails --uid 1000 --gid 1000 --create-home --shell /bin/bash && \
    mkdir -p data && \
    chown -R 1000:1000 db log storage tmp data
USER 1000:1000

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

# Start server on port 3000
EXPOSE 3000
CMD ["./bin/rails", "server", "-b", "0.0.0.0"]