Sample Caddyfile using git middleware.
$ printf "0.0.0.0\ngit github.com/abiosoft/webtest" > Caddyfile
$ docker run -d -v `pwd`/Caddyfile:/etc/Caddyfile -p 2015:2015 abiosoft/caddy
Point your browser to http://127.0.0.1:2015
.
Caddyfile: /etc/Caddyfile
Server root: /srv
Serve /var/www/html/mysite
with Caddy
$ docker run -d -v /var/www/html/mysite:/srv -v path/to/Caddyfile:/etc/Caddyfile -p 2015:2015 abiosoft/caddy