Dockerfile.exmaple

############################################################
# Example Dockerfile that runs a dedicated game server
# with SteamCMD.
############################################################

FROM opensuse/leap:15.6

LABEL maintainer="code@yanwk.fun"

# Install runtimes & SteamCMD.
# When done, disable all Zypper repos.
RUN zypper install --no-confirm --no-recommends --auto-agree-with-licenses \
        libSDL2-2_0-0 \
        steamcmd \
    && zypper modifyrepo --disable --all \
    && rm -rf /var/cache/zypp/*

# Run SteamCMD for the first time, let it update & install some files,
# so other low-privilege users could run it properly.
# Clear /tmp when done.
RUN steamcmd +'quit' \
    && rm -rf /root/Steam/appcache/httpcache/* \ 
    && rm -rf /tmp/*

# Create a low-privilege user.
RUN set -eux \
    && sed -i 's/^CREATE_MAIL_SPOOL=yes/CREATE_MAIL_SPOOL=no/' /etc/default/useradd \
    && mkdir -p /home/runner \
    && groupadd runner \
    && useradd runner -g runner -d /home/runner \
    && chown runner:runner /home/runner

USER runner:runner
WORKDIR /home/runner

ENV STEAMAPPID 1007
ENV GAMEDIR "/home/runner/Steam/steamapps/common/Steamworks SDK Redist"

# Make directory before mount volume (or it will be root-owned).
# Make necessary symlink for SteamCMD.
RUN set -eux \
    && mkdir -p "${GAMEDIR}" \
    && mkdir -p /home/runner/Steam \
    && mkdir -p /home/runner/.steam/sdk32 \
    && mkdir -p /home/runner/.steam/sdk64 \
    && ln -s /usr/lib/steamcmd/linux32/steamclient.so /home/runner/.steam/sdk32/steamclient.so \
    && ln -s /usr/lib/steamcmd/linux64/steamclient.so /home/runner/.steam/sdk64/steamclient.so

# Mount the whole game server folder as persistence.
# Could be optimized if the game server is data-program separated, but needs redesign.
VOLUME $GAMEDIR

# "EXPOSE" does not actually publish the port, it informs container which port needs to.
EXPOSE 8080/tcp
EXPOSE 8081/tcp

# If the executable file doesn't exist, SteamCMD will download, install and validate the server.
# If exists, SteamCMD will try to update the server, but without validation (or config files could be replaced).
CMD if [[ -f "${GAMEDIR}/DedicatedServerApp" ]] ; then \
        steamcmd @ShutdownOnFailedCommand @NoPromptForPassword +login anonymous +app_update ${STEAMAPPID} +'quit' ; \
    else \
        steamcmd @ShutdownOnFailedCommand @NoPromptForPassword +login anonymous +app_update ${STEAMAPPID} validate +'quit' ; \
    fi \
    && "${GAMEDIR}/DedicatedServerApp"