testing build and test

backend/Dockerfile

@@ -1,39 +1,58 @@
-FROM hexpm/elixir:1.15.7-erlang-26.1.2-alpine-3.18.4 AS build
+ARG ELIXIR_VERSION=1.18.4
+ARG OTP_VERSION=27.3.4.8
+ARG DEBIAN_VERSION=trixie-20260223-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
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends build-essential git \
+  && rm -rf /var/lib/apt/lists/*
 
-RUN apk add --no-cache build-base git
 WORKDIR /app
-RUN mix local.hex --force && \
-  mix local.rebar --force
-ENV MIX_ENV=prod
+
+RUN mix local.hex --force \
+  && mix local.rebar --force
+
+ENV MIX_ENV="prod"
+
 COPY mix.exs mix.lock ./
 RUN mix deps.get --only $MIX_ENV
 RUN mkdir config
-
 COPY config/config.exs config/${MIX_ENV}.exs config/
 RUN mix deps.compile
-COPY lib lib
-RUN mix compile
-COPY config/runtime.exs config/
 
 COPY priv priv
+COPY lib lib
+
+RUN mix compile
+
+COPY config/runtime.exs config/
 RUN mix release
 
-FROM alpine:3.18.4 AS app
+FROM ${RUNNER_IMAGE} AS final
 
-RUN apk add --no-cache libstdc++ openssl ncurses-libs bash
-ENV USER="elixir"
-WORKDIR /app
-RUN addgroup -g 1000 $USER && \
-  adduser -D -u 1000 -G $USER $USER
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends libstdc++6 openssl libncurses6 locales ca-certificates \
+  && rm -rf /var/lib/apt/lists/*
 
-COPY --from=build --chown=elixir:elixir /app/_build/prod/rel/backend ./
+RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen \
+  && locale-gen
 
-USER elixir
+ENV LANG=en_US.UTF-8
+ENV LANGUAGE=en_US:en
+ENV LC_ALL=en_US.UTF-8
+
+WORKDIR "/app"
+RUN chown nobody /app
+
+ENV MIX_ENV="prod"
+
+COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/backend ./
+
+USER nobody
 
-ENV HOME=/app
-ENV MIX_ENV=prod
 ENV PHX_SERVER=true
-
-EXPOSE 4000 4369 9000-9100
-
 CMD ["/app/bin/backend", "start"]