The doc.env file definition WWW_PATH is invalid

  docker, question

File directory:
.env
docker-compose.yml

.env:

# root directory
 ROOT_PATH=./services
 # Project Path
 WWW_PATH=./www
 
 # nginx
 NGINX_WWW_DIR=$(WWW_PATH)

docker-compose.yml

- ${NGINX_WWW_DIR}:/data/www:rw

Error: named volume “www.path:/data/www.rw” isused in service “nginx” but no declaration was found in the volumes section.
Question:

The constant defined in the. env file is invalid, how can it be made valid?
NGINX_WWW_DIR=$(WWW_PATH)

The brackets here should be removed.

=>

NGINX_WWW_DIR=$WWW_PATH

Or change to braces

NGINX_WWW_DIR=${WWW_PATH}

However, according to docker volume mapping rules, it is best to use absolute paths, that is

NGINX_WWW_DIR=$PWD/$WWW_PATH

-v should only accept absolute path.