update to sha256 for checksum verification (#407)

* update sha1 to sha256 for checksum validation

* switch jinja templating to docker build-args

docker/Dockerfile

@@ -0,0 +1,49 @@
+FROM frolvlad/alpine-glibc:alpine-3.12
+
+LABEL maintainer="https://github.com/factoriotools/factorio-docker"
+
+ARG USER=factorio
+ARG GROUP=factorio
+ARG PUID=845
+ARG PGID=845
+
+# version checksum of the archive to download
+ARG VERSION
+ARG SHA256
+
+ENV PORT=34197 \
+    RCON_PORT=27015 \
+    VERSION=${VERSION:?} \
+    SHA256=${SHA256:?} \
+    SAVES=/factorio/saves \
+    CONFIG=/factorio/config \
+    MODS=/factorio/mods \
+    SCENARIOS=/factorio/scenarios \
+    SCRIPTOUTPUT=/factorio/script-output \
+    PUID="$PUID" \
+    PGID="$PGID"
+
+SHELL ["/bin/ash", "-eo", "pipefail", "-c"]
+RUN set -ox pipefail \
+    && archive="/tmp/factorio_headless_x64_$VERSION.tar.xz" \
+    && mkdir -p /opt /factorio \
+    && apk add --update --no-cache --no-progress bash binutils curl file gettext jq libintl pwgen shadow su-exec \
+    && curl -sSL "https://www.factorio.com/get-download/$VERSION/headless/linux64" -o "$archive" \
+    && echo "$SHA256  $archive" | sha256sum -c \
+    || (sha256sum "$archive" && file "$archive" && exit 1) \
+    && tar xf "$archive" --directory /opt \
+    && chmod ugo=rwx /opt/factorio \
+    && rm "$archive" \
+    && ln -s "$SCENARIOS" /opt/factorio/scenarios \
+    && ln -s "$SAVES" /opt/factorio/saves \
+    && mkdir -p /opt/factorio/config/ \
+    && addgroup -g "$PGID" -S "$GROUP" \
+    && adduser -u "$PUID" -G "$GROUP" -s /bin/sh -SDH "$USER" \
+    && chown -R "$USER":"$GROUP" /opt/factorio /factorio
+
+COPY files/*.sh /
+COPY files/config.ini /opt/factorio/config/config.ini
+
+VOLUME /factorio
+EXPOSE $PORT/udp $RCON_PORT/tcp
+ENTRYPOINT ["/docker-entrypoint.sh"]