Try to build the chroot outside first

We need priviliges for the debootstrap, passing this to buildx is far from easy and we only need a simple setup

Author: vmcj

docker-gitlabci/Dockerfile

@@ -64,15 +64,4 @@ RUN wget $GITHUBDICTIONARY -O $CODESPELLDICTLOCATION
 RUN mkdir -p /run/php \
  && rm /etc/php/*/fpm/pool.d/www.conf
 
-RUN du -sh /* || true
-
-# Cache the chroot
-RUN cd /                         && wget https://github.com/DOMjudge/domjudge/archive/refs/heads/main.zip
-RUN cd /                         && unzip main.zip
-RUN cd /domjudge-main            && make configure
-RUN cd /domjudge-main            && ./configure --with-domjudge-user=domjudge
-RUN cd /domjudge-main/misc-tools && make dj_make_chroot
-RUN cd /domjudge-main/misc-tools && ./dj_make_chroot
-RUN                                 rm -rf /domjudge-main
-
-RUN du -sh /* || true
+COPY ["chroot", "/chroot"]

docker-gitlabci/build.sh

@@ -20,6 +20,16 @@ else
 	REGISTRY=$2
 fi
 
+echo "[..] Building an example chroot..."
+wget https://github.com/DOMjudge/domjudge/archive/refs/heads/main.zip
+unzip main.zip
+cd domjudge-main
+  make configure
+  ./configure --with-domjudge-user=domjudge --with-judgehost_chrootdir=`pwd`/chroot
+cd misc-tools
+  make dj_make_chroot
+  sudo ./dj_make_chroot
+
 echo "[..] Building Docker image for Gitlab CI..."
 cp -r ../docker-contributor/php-config ./
 docker build -t "${REGISTRY}:${VERSION}" .