Dockerfile

# syntax = docker/dockerfile:experimental

# Dockerfile used to build a deployable image for a Rails application.
# Adjust as required.
#
# Common adjustments you may need to make over time:
#  * Modify version numbers for Ruby, Bundler, and other products.
#  * Add library packages needed at build time for your gems, node modules.
#  * Add deployment packages needed by your application
#  * Add (often fake) secrets needed to compile your assets

#######################################################################

# Learn more about the chosen Ruby stack, Fullstaq Ruby, here:
#   https://github.com/evilmartians/fullstaq-ruby-docker.
#
# We recommend using the highest patch level for better security and
# performance.

ARG RUBY_VERSION=3.1.3
ARG VARIANT=bullseye
FROM ruby:${RUBY_VERSION}-${VARIANT} as base

LABEL fly_launch_runtime="rails"

ARG BUNDLER_VERSION=2.3.26

ARG RAILS_ENV=production
ARG BUNDLE_WITHOUT=development:test
ARG BUNDLE_PATH=vendor/bundle
ENV RAILS_ENV=${RAILS_ENV}
ENV BUNDLE_PATH ${BUNDLE_PATH}
ENV BUNDLE_WITHOUT ${BUNDLE_WITHOUT}

ENV RAILS_SERVE_STATIC_FILES true
ENV RAILS_LOG_TO_STDOUT true

RUN mkdir /app
WORKDIR /app
RUN mkdir -p tmp/pids

#######################################################################

# install packages only needed at build time

FROM base as build_deps

ARG BUILD_PACKAGES="git build-essential libpq-dev wget vim curl gzip xz-utils libsqlite3-dev"
ENV BUILD_PACKAGES ${BUILD_PACKAGES}

RUN --mount=type=cache,id=dev-apt-cache,sharing=locked,target=/var/cache/apt \
    --mount=type=cache,id=dev-apt-lib,sharing=locked,target=/var/lib/apt \
    apt-get update -qq && \
    apt-get install --no-install-recommends -y ${BUILD_PACKAGES} \
    && rm -rf /var/lib/apt/lists /var/cache/apt/archives

#######################################################################

# install gems

FROM build_deps as gems

RUN gem update --system --no-document && \
    gem install -N bundler -v ${BUNDLER_VERSION}

COPY Gemfile* ./
RUN bundle install &&  rm -rf vendor/bundle/ruby/*/cache

#######################################################################

# install deployment packages

FROM base

ARG DEPLOY_PACKAGES="postgresql-client file vim curl gzip libsqlite3-0 nodejs"
ENV DEPLOY_PACKAGES=${DEPLOY_PACKAGES}

RUN --mount=type=cache,id=prod-apt-cache,sharing=locked,target=/var/cache/apt \
    --mount=type=cache,id=prod-apt-lib,sharing=locked,target=/var/lib/apt \
    apt-get update -qq && \
    apt-get install --no-install-recommends -y \
    ${DEPLOY_PACKAGES} \
    && rm -rf /var/lib/apt/lists /var/cache/apt/archives

# copy installed gems
COPY --from=gems /app /app
COPY --from=gems /usr/local/lib/ruby /usr/local/lib/ruby
COPY --from=gems /usr/local/bundle /usr/local/bundle

#######################################################################

# Deploy your application
COPY . .

EXPOSE 8080

ENV WEB_CONCURRENCY 1
ENV MAX_THREADS 2
ENV RACK_ENV production
ENV PUMA_WORKER_TIMEOUT 25
ENV PUMA_WORKER_SHUTDOWN_TIMEOUT 25
ENV DATABASE_URL ""
ARG SERVER_COMMAND="bundle exec puma --debug -p 8080 config.ru"

ENV SERVER_COMMAND ${SERVER_COMMAND}
CMD ${SERVER_COMMAND}