Dockerfile

############################################################
# Dockerfile that contains SteamCMD
############################################################
FROM debian:bullseye-slim as build_stage

LABEL maintainer="walentinlamonos@gmail.com"
ARG PUID=1000

ENV USER steam
ENV HOMEDIR "/home/${USER}"
ENV STEAMCMDDIR "${HOMEDIR}/steamcmd"

RUN set -x \
	# Install, update & upgrade packages
	&& apt-get update \
	&& apt-get install -y --no-install-recommends --no-install-suggests \
		lib32stdc++6=10.2.1-6 \
		lib32gcc-s1=10.2.1-6 \
		ca-certificates=20210119 \
		nano=5.4-2+deb11u2 \
		curl=7.74.0-1.3+deb11u11 \
		locales=2.31-13+deb11u10 \
	&& sed -i -e 's/# en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen \
	&& dpkg-reconfigure --frontend=noninteractive locales \
	# Create unprivileged user
	&& useradd -u "${PUID}" -m "${USER}" \
	# Download SteamCMD, execute as user
	&& su "${USER}" -c \
		"mkdir -p \"${STEAMCMDDIR}\" \
                && curl -fsSL 'https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz' | tar xvzf - -C \"${STEAMCMDDIR}\" \
                && \"./${STEAMCMDDIR}/steamcmd.sh\" +quit \
                && ln -s \"${STEAMCMDDIR}/linux32/steamclient.so\" \"${STEAMCMDDIR}/steamservice.so\" \
                && mkdir -p \"${HOMEDIR}/.steam/sdk32\" \
                && ln -s \"${STEAMCMDDIR}/linux32/steamclient.so\" \"${HOMEDIR}/.steam/sdk32/steamclient.so\" \
                && ln -s \"${STEAMCMDDIR}/linux32/steamcmd\" \"${STEAMCMDDIR}/linux32/steam\" \
                && mkdir -p \"${HOMEDIR}/.steam/sdk64\" \
                && ln -s \"${STEAMCMDDIR}/linux64/steamclient.so\" \"${HOMEDIR}/.steam/sdk64/steamclient.so\" \
                && ln -s \"${STEAMCMDDIR}/linux64/steamcmd\" \"${STEAMCMDDIR}/linux64/steam\" \
                && ln -s \"${STEAMCMDDIR}/steamcmd.sh\" \"${STEAMCMDDIR}/steam.sh\"" \
	# Symlink steamclient.so; So misconfigured dedicated servers can find it
 	&& ln -s "${STEAMCMDDIR}/linux64/steamclient.so" "/usr/lib/x86_64-linux-gnu/steamclient.so" \
	&& rm -rf /var/lib/apt/lists/*

FROM build_stage AS bullseye-root
WORKDIR ${STEAMCMDDIR}

FROM bullseye-root AS bullseye
# Switch to user
USER ${USER}