Discourse didn’t use docker-compose as I know.
I believe add the below command to the before_web hook can make it work, like what web.china.template.yml does.
git config --global http.proxy socks5://yourproxy:port
and if you don’t need proxy anymore after build, add below to the after_web hook:
git config --global --unset http.proxy
All hooks are running inside the container so I don’t think it would be a problem