Caddy Serving Files, Local Subdomains & Environment Variables

Caddy web server has the option to directly serve files. It is especially useful when looking to display a static web pages under subdomains alongside more complex solutions.

Adapting your Docker Compose installation: Link to heading

Under volumes, add volume you wish Docker to copy to the container so that section should look like this:

    volumes:
      - ./caddy/Caddyfile:/etc/caddy/Caddyfile
      - ./caddy/static:/srv
      - ./caddy/config:/config
      - ./caddy/data:/data
      - ./subdomain_files:/www/html

Caddy configuration Link to heading

In order to have Caddy serve the files, we have to tell it where the files are located and that it needs to serve them.

root is the option we must specify, alongside a path, to locate the folder/files. With * we can tell Caddy to serve all files within the specified folder, therefore index.html will be our domain’s homepage, while other denomination will appear as DOMAIN_NAME/you_other_file.html.

Your Caddyfile root path for the domain’s files should reflect the path used in docker-compose.yml; here /www/html.

file_server tells Caddy to take care of serving them.

Overall Caddyfile should look like this:

{$DOMAIN_NAME} {
    root * /www/html
    file_server
}
www.{$DOMAIN_NAME} {
    redir https://{$DOMAIN_NAME}{uri}
}

Variables in local dev environment Link to heading

Another way to use environement variables in Caddy for both development and production is to give a default option. This works best when using subdomain on local machines for example.

{$SUBDOMAIN_NAME:subdomain.localhost} {
    root * /www/html
    file_server
}
www.{$SUBDOMAIN_NAME:subdomain.localhost} {
    redir https://{$SUBDOMAIN_NAME:subdomain.localhost}{uri}
}