directory structure

Caddyfile  config  data  docker-compose.yml  site

Caddy file

:80
root * /srv/
file_server browse

docker-compose

version: "3.7"

services:
  caddy:
    image: caddy:2.3.0
    restart: unless-stopped
    ports:
      - "8081:80"
    volumes:
      - $PWD/Caddyfile:/etc/caddy/Caddyfile
      - ./site:/srv
      - ./data:/data
      - ./config:/config