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@manufarez
Created February 19, 2024 18:46
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Dockerfile that works with Kamal
# 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:$RUBY_VERSION-slim as base
# Rails app lives here
WORKDIR /rails
# Set production environment
ENV RAILS_ENV="production" \
BUNDLE_DEPLOYMENT="1" \
BUNDLE_PATH="/usr/local/bundle" \
BUNDLE_WITHOUT="development"
# Throw-away build stage to reduce size of final image
FROM base as build
# Install packages needed to build gems
RUN apt-get update -qq && \
apt-get install --no-install-recommends -y build-essential git libpq-dev libvips pkg-config
# Install application gems
COPY Gemfile Gemfile.lock ./
RUN bundle install && \
rm -rf ~/.bundle/ "${BUNDLE_PATH}"/ruby/*/cache "${BUNDLE_PATH}"/ruby/*/bundler/gems/*/.git && \
bundle exec bootsnap precompile --gemfile
# Copy application code
COPY . .
# Precompile bootsnap code for faster boot times
RUN bundle exec bootsnap precompile app/ lib/
# 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
# Install packages needed for deployment
RUN apt-get update -qq && \
apt-get install --no-install-recommends -y curl libvips postgresql-client && \
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"]
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