# This file is based on these images:
#
#   - https://hub.docker.com/r/hexpm/elixir/tags - for the builder image
#     E.g.: docker.io/hexpm/elixir:1.20.1-erlang-29.0.2-debian-trixie-20260610-slim
#   - https://hub.docker.com/_/debian/tags?name=trixie-20260610-slim - for the runner image
#     E.g.: docker.io/debian:trixie-20260610-slim
#
# Find builder and runner images on Docker Hub or on Hex's Build Server (Bob).
# We recommend using Bob's Web UI to find recent tags:
#
#   - https://bob.hex.pm/docker
#
# We suggest using the same Debian version for both the builder and runner images.
#
# We suggest Debian/Ubuntu instead of Alpine to avoid production compatibility issues
# (such as DNS resolution failures, and dynamically linked NIFs/precompiled binaries).
#
# For finding packages in Debian, search on https://packages.debian.org/.

ARG ELIXIR_VERSION=1.20.1
ARG OTP_VERSION=29.0.2
ARG DEBIAN_VERSION=trixie-20260610-slim

ARG BUILDER_IMAGE="docker.io/hexpm/elixir:${ELIXIR_VERSION}-erlang-${OTP_VERSION}-debian-${DEBIAN_VERSION}"
ARG RUNNER_IMAGE="docker.io/debian:${DEBIAN_VERSION}"

FROM ${BUILDER_IMAGE} AS builder

# install build dependencies
RUN apt-get update \
  && apt-get install -y --no-install-recommends build-essential git \
  && rm -rf /var/lib/apt/lists/*

# prepare build dir
WORKDIR /app

# install hex + rebar
RUN mix local.hex --force \
  && mix local.rebar --force

# set build ENV
ENV MIX_ENV="prod"

# install mix dependencies
COPY mix.exs mix.lock ./
RUN mix deps.get --only $MIX_ENV
RUN mkdir config

# copy compile-time config files before we compile dependencies
# to ensure any relevant config change will trigger the dependencies
# to be re-compiled.
COPY config/config.exs config/${MIX_ENV}.exs config/
RUN mix deps.compile

RUN mix assets.setup

COPY priv priv

COPY lib lib

# Compile the release
RUN mix compile

COPY assets assets

# compile assets
RUN mix assets.deploy

# Changes to config/runtime.exs don't require recompiling the code
COPY config/runtime.exs config/

COPY rel rel
RUN mix release

# start a new build stage so that the final image will only contain
# the compiled release and other runtime necessities
FROM ${RUNNER_IMAGE} AS final

# git: Tarakan shells out to git for pinned-commit snapshots, blobless
#      mirrors, and smart-HTTP/SSH hosting — it must be present at runtime.
# openssh-client: Tarakan.GitSSH.Server generates its ed25519 host key with
#      ssh-keygen on first boot. Without it the daemon fails to start, and
#      because that failure stops a supervised child, the whole release
#      refuses to boot rather than merely losing SSH.
# tini: reaps the many short-lived git subprocesses so they don't become
#       zombies.
RUN apt-get update \
  && apt-get install -y --no-install-recommends libstdc++6 openssl libncurses6 locales ca-certificates git openssh-client tini \
  && rm -rf /var/lib/apt/lists/*

# Set the locale
RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen \
  && locale-gen

ENV LANG=en_US.UTF-8
ENV LANGUAGE=en_US:en
ENV LC_ALL=en_US.UTF-8

WORKDIR "/app"
RUN chown nobody /app

# Persistent storage for hosted repositories, the mirror hot-tier, and the SSH
# host key. These are mounted as volumes in production; creating them owned by
# nobody means a fresh named volume inherits writable ownership. ssh is 0700
# because ssh-keygen refuses to use a key whose directory is group-readable.
RUN mkdir -p /app/storage/mirrors /app/storage/hosted /app/storage/ssh \
  && chmod 700 /app/storage/ssh \
  && chown -R nobody /app/storage

# set runner ENV
ENV MIX_ENV="prod"

# Only copy the final release from the build stage
COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/tarakan ./

USER nobody

# tini reaps zombie git subprocesses.
ENTRYPOINT ["/usr/bin/tini", "--"]

CMD ["/app/bin/server"]