Docker - Can't share data between containers within a volume (docker-compose 3)

Question

I have some containers for a web app for now (nginx, gunicorn, postgres and node to build static files from source and a React server side rendering). In a Dockerfile for the no

Answer 1

Explanation of what happens step by step

Dockerfile.node

    ...
    COPY ./client /usr/src
    ...

docker-compose.yml

services:
  ...
  node:
    ...
    volumes:
      - ./server/nginx.conf:/etc/nginx/nginx.conf:ro
      - vnode:/usr/src
  ...
volumes:
  vnode:

1. docker-compose up creates with this Dockerfile.node and docker-compose section a named volume with data saved in /usr/src.

---

Dockerfile.nginx

FROM nginx:latest

COPY ./server/nginx.conf /etc/nginx/nginx.conf

RUN mkdir -p /var/www/tg/static

EXPOSE 80
EXPOSE 443

CMD ["nginx", "-g", "daemon off;"]

2. That produces that nginx containers created with docker-compose will have an empty /var/www/tg/static/

---

docker-compose.yml

 ...
 nginx:
    build:
      context: .
      dockerfile: ./Dockerfile.nginx
    container_name: tg_nginx
    restart: always
    volumes:
      - ./server/nginx.conf:/etc/nginx/nginx.conf:ro
      - vnode:/var/www/tg/static
    ports:
      - "80:80"
      - "443:443"
    depends_on:
      - node
      - gunicorn
    networks:
      - nw_web_tg

 volumes:
   vdata:
   vnode:

3. docker-compose up will produce that vnode named volume is created and filled with data from /var/www/tg/static (empty by now) to existing vnode.

So, at this point, - nginx container has /var/www/tg/static empty because it was created empty (see mkdir in Dockerfile.nginx) - node container has /usr/src dir with client file (see that was copied in Dockerfile.node) - vnode has content of /usr/src from node and /var/www/tg/static from nginx.

Definitively, to pass data from /usr/src from your node container to /var/www/tg/static in nginx container you need to do something that is not very pretty because Docker hasn't developed another way yet: You need to combine named volume in source folder with bind volume in destination:

 nginx:
     build:
       context: .
       dockerfile: ./Dockerfile.nginx
     container_name: tg_nginx
     restart: always
     volumes:
       - ./server/nginx.conf:/etc/nginx/nginx.conf:ro
       - /var/lib/docker/volumes/vnode/_data:/var/www/tg/static
     ports:
       - "80:80"
       - "443:443"
     depends_on:
       - node
       - gunicorn
     networks:
       - nw_web_tg

Just change in docker-compose - vnode:/var/www/tg/static by - /var/lib/docker/volumes/vnode/_data:/var/www/tg/static