It's not pretty but this works with docker images ``` FROM debian:bookworm

It's not pretty but this works with docker images ``` FROM debian:bookworm ARG APT_CACHE RUN if [ ! -z "$APT_CACHE" ]; then \ echo 'Acquire::http { Proxy "'$APT_CACHE'"; };' >> /etc/apt/apt.conf.d/01proxy; \ fi && \ ... rest of your commands go here ... ``` Then run `docker build --build-arg APT_CACHE=http://aptcacheraddress:port http://aptcacheraddress:port` If the build arg isn't set it will simply not use apt cacher and proceed as normal.