Dockerfile

# syntax=docker/dockerfile:1

ARG BASE_IMAGE_TAG=latest

FROM ruby:${BASE_IMAGE_TAG}

# Explicitely define locale
# as advised in https://github.com/docker-library/docs/blob/master/ruby/content.md#encoding
ENV LANG="C.UTF-8"

ARG RUBYGEMS_VERSION_ARG="" \
    BUNDLER_VERSION_ARG=""

# Define dependencies base versions
# Note: NodeJS is capped to 14.x on Jessie and 16.x on Stretch (due to `libc` requirements)
ENV NODE_VERSION="20" \
    GOSU_VERSION="1.17"

# Define some default variables
ENV PORT="5000" \
    BUNDLE_PATH="/bundle" \
    BUNDLE_BIN="/bundle/bin" \
    BUNDLE_APP_CONFIG="/bundle" \
    GEM_HOME="/bundle/global" \
    PATH="/bundle/bin:/bundle/global/bin:${PATH}" \
    HISTFILE="/config/.bash_history" \
    GIT_COMMITTER_NAME="Just some fake name to be able to git-clone" \
    GIT_COMMITTER_EMAIL="whatever@this-user-is-not-supposed-to-git-push.anyway" \
    DISABLE_SPRING="true"

# Install dependencies
RUN set -eux; \
    osType="$(sed -n 's|^ID=||p' /etc/os-release)"; \
    \
    case "${osType}" in \
      alpine) \
        alpineMajorVersion=$(sed -nr 's/^VERSION_ID=(\d+\.\d+).*/\1/p' /etc/os-release); \
        \
        # Use `libpq-dev` (~20MB) rather than `postgresql-dev` (~200MB) if available
        # (the former was extracted from the latter in Alpine 3.15)
        case ${alpineMajorVersion} in \
          3.3|3.4|3.5|3.6|3.7|3.8|3.9|3.10|3.11|3.12|3.13|3.14) libpqPackage="postgresql-dev" ;; \
          3.15|*) libpqPackage="libpq-dev" ;; \
        esac; \
        \
        apk add --no-cache \
          alpine-sdk \
          openssh \
          curl \
          jq \
          nano \
          nodejs \
          postgresql \
          vim \
          yarn \
          ${libpqPackage} \
        ; \
      ;; \
      \
      debian|ubuntu) \
        # Fix Jessie & Stretch APT sources (they have been moved to http://archive.debian.org)
        if [ -f /etc/apt/sources.list ]; then \
          sed -i -r \
            -e '/(jessie|stretch)[-\/]updates/d' \
            -e 's|http://(deb\|httpredir).debian.org/debian (jessie\|stretch)|http://archive.debian.org/debian \2|' \
            /etc/apt/sources.list; \
        fi; \
        \
        # Detect Debian version
        apt-get update; \
        apt-get install --assume-yes --no-install-recommends --no-install-suggests --force-yes \
          apt-transport-https \
          lsb-release \
        ; \
        debianReleaseCodename=$(lsb_release -cs); \
        \
        # Fix LetsEncrypt expired CA on older Debian releases
        case ${debianReleaseCodename} in \
          jessie|buster|stretch) \
            apt-get install --assume-yes --no-install-recommends --no-install-suggests --force-yes \
              ca-certificates \
              curl \
              $([ "${debianReleaseCodename}" = "jessie" ] && echo "libssl1.0.0") \
            ; \
            sed -i 's|mozilla/DST_Root_CA_X3.crt|!mozilla/DST_Root_CA_X3.crt|g' /etc/ca-certificates.conf; \
            update-ca-certificates; \
          ;; \
        esac; \
        \
        # Add PostgreSQL APT repository
        curl -sSL https://www.postgresql.org/media/keys/ACCC4CF8.asc | gpg --dearmor > /etc/apt/trusted.gpg.d/apt.postgresql.org.gpg; \
        case ${debianReleaseCodename} in \
          jessie|stretch) echo "deb https://apt-archive.postgresql.org/pub/repos/apt ${debianReleaseCodename}-pgdg-archive main" ;; \
          *) echo "deb https://apt.postgresql.org/pub/repos/apt/ ${debianReleaseCodename}-pgdg main" ;; \
        esac > /etc/apt/sources.list.d/pgdg.list; \
        \
        # Add NodeJS APT repository
        case ${debianReleaseCodename} in \
          jessie) curl -fsSL https://deb.nodesource.com/setup_14.x ;; \
          stretch) curl -fsSL https://deb.nodesource.com/setup_16.x ;; \
          *) curl -fsSL https://deb.nodesource.com/setup_${NODE_VERSION}.x ;; \
        esac | bash; \
        \
        # Install everything
        apt-get update; \
        apt-get install --assume-yes --no-install-recommends --no-install-suggests --force-yes \
          jq \
          nano \
          nodejs \
          postgresql-client \
          vim \
        ; \
        \
        # Cleanup
        rm -rf /var/lib/apt/lists/*; \
        \
        # Install Yarn (via NPM)
        npm install --global yarn; \
        \
        # Install Heroku CLI (standalone tarball)
        curl -sSL curl https://cli-assets.heroku.com/install.sh | sh; \
      ;; \
    esac;

# Install `gosu`
ARG TARGETARCH # provided by Docker multi-platform support: https://docs.docker.com/build/guide/multi-platform
RUN set -eux; \
    osType="$(sed -n 's|^ID=||p' /etc/os-release)"; \
    export GNUPGHOME="$(mktemp -d)"; \
    \
    # Install GPG on Alpine (for signature verification)
    [ "${osType}" = "alpine" ] && apk add --no-cache --virtual .gosu-deps gnupg || :; \
    \
    # Fetch author public key
    for keyserver in $(shuf -e keyserver.ubuntu.com keys.openpgp.org keys.mailvelope.com); do \
      gpg --batch --no-tty --keyserver "${keyserver}" --recv-keys "B42F6819007F00F88E364FD4036A9C25BF357DD4" && break || :; \
    done; \
    \
    # Download binary
    curl -sSL -o /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/${GOSU_VERSION}/gosu-${TARGETARCH}"; \
    chmod +x /usr/local/bin/gosu; \
    \
    # Verify binary signature
    curl -sSL "https://github.com/tianon/gosu/releases/download/${GOSU_VERSION}/gosu-${TARGETARCH}.asc" \
      | gpg --batch --verify - /usr/local/bin/gosu; \
    \
    # Cleanup
    command -v gpgconf && gpgconf --kill all || :; \
    rm -rf "${GNUPGHOME}"; \
    unset -v GNUPGHOME; \
    [ "${osType}" = "alpine" ] && apk del --no-network .gosu-deps || :;

# Install GEM dependencies
# Note: we still need Bundler 1.x because Bundler auto-switches to it when it encounters a Gemfile.lock with BUNDLED WITH 1.x
RUN gem update --system ${RUBYGEMS_VERSION_ARG} \
 && gem install bundler${BUNDLER_VERSION_ARG:+:${BUNDLER_VERSION_ARG}} \
 && gem install bundler:1.17.3

# Add dot files to the home directory skeleton (they persist IRB/Pry/Rails console history, configure Yarn, etc…)
COPY dotfiles/* /etc/skel/

# Create expected mount points
RUN mkdir -p /app /bundle /config

# Configure the main working directory.
WORKDIR /app

# Expose listening port to the Docker host, so we can access it from the outside.
EXPOSE ${PORT}

# Use entrypoints that switch to unprivileged user, install foreman, install dependencies (bundler & yarn), and fix a Rails server issue
COPY entrypoints/* /usr/local/bin/
ENTRYPOINT ["gosu-entrypoint", "foreman-entrypoint", "bundler-entrypoint", "yarn-entrypoint", "rails-entrypoint"]

# The main command to run when the container starts is to start whatever the Procfile defines
CMD ["foreman", "start", "-m", "all=1,release=0"]