Dockerfile

# syntax = docker/dockerfile:1

# Make sure it matches the Ruby version in .ruby-version and Gemfile
ARG RUBY_VERSION=3.2.2
ARG TARGETPLATFORM=linux/amd64
FROM 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 --platform=$TARGETPLATFORM base as build

# Install packages need to build gems
RUN apt-get update -qq && \
    apt-get install -y build-essential git 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

# Copy application code
COPY . .

# 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

# Configure environment defaults
ENV HTTP_IDLE_TIMEOUT=60
ENV HTTP_READ_TIMEOUT=300
ENV HTTP_WRITE_TIMEOUT=300

# Install packages needed to run the application
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y libsqlite3-0 libvips curl ffmpeg redis && \
    rm -rf /var/lib/apt/lists /var/cache/apt/archives

# Run and own the application files as a non-root user for security
RUN useradd rails
USER rails:rails

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

# Set version and revision
ARG APP_VERSION
ENV APP_VERSION=$APP_VERSION
ARG GIT_REVISION
ENV GIT_REVISION=$GIT_REVISION

# Expose ports for HTTP and HTTPS
EXPOSE 80 443

# Start the server by default, this can be overwritten at runtime
CMD ["bin/boot"]