How to deploy my Express/React app to server with docker-compose and Dockerfiles

Question

Hi, I'm trying to deploy my app to production with Docker, but I struggle a lot. Here is the structure from the root folder :

• a server folder : runs with Express on port 4000
• a web folder : a React app running on 3000 (locally), that needs to run on 80 on my server
• a docker-compose.prod.yml file in the root folder

What I'm currently trying :

• the docker-compose.prod.yml is running a Postgres service (port 5432), as well as web and server's respective Dockerfile
• a Dockerfile in both web and server folders
• I yarn build both server and web folders locally and send everything on my server
• on my server, I run docker build -f web/Dockerfile.prod -t app_web ./web and docker build -f server/Dockerfile.prod -t app_server ./server to build both images
• finally, I run docker-compose -f docker-compose.prod.yml up

My problem :

The server container throws Error: Cannot find module '...' although I run yarn install --production in its Dockerfile (it may be related to volumes?)

Also, when I run docker run -it -p 80:80 app_web and docker-compose up, the web container acts differently when visiting my server IP address : in the first case, the app displays well, in the second case, a page is listing my web folder content (all files and folders)

I'd really appreciate help as I'm a bit new to Docker in production (should I use docker machine? are my folders structure / docker-compose / Dockerfiles wrong?)

docker-compose.prod.yml :

version: "3"
services:
  db:
    image: postgres:latest
    restart: on-failure
    environment:
      POSTGRES_DB: ${DB_NAME}
      POSTGRES_USER: ${DB_NAME}
      POSTGRES_PASSWORD: ${DB_PASSWORD}
    ports:
      - 5432:5432
    volumes:
      - ./.db/data:/var/lib/postgresql/data

  server:
    container_name: app_server
    build:
      context: ./server
      dockerfile: Dockerfile.prod
    volumes:
      - ./server:/app/server
    ports:
      - 4000:4000
    depends_on:
      - db

  web:
    container_name: app_web
    build:
      context: ./web
      dockerfile: Dockerfile.prod
    volumes:
      - ./web:/app/web
    ports:
      - 80:80
    depends_on:
      - db

server/Dockerfile.prod :

FROM mhart/alpine-node:11 AS builder
WORKDIR /app/server
COPY package.json ./
RUN yarn install --production
COPY . .

FROM mhart/alpine-node
WORKDIR /app/server
COPY --from=builder /app/server .
CMD ["node", "/app/server/dist"]

web/Dockerfile.prod :

FROM mhart/alpine-node:11 AS builder
WORKDIR /app/web
COPY package.json .
RUN yarn install --production
COPY . .

FROM mhart/alpine-node
RUN yarn global add serve
WORKDIR /app/web
COPY --from=builder /app/web/build .
CMD ["serve", "-p", "80", "-s", "."]

Answer 1

I found the solution, eventually it was just a volume issue, I had to add a specific line for modules :

volumes:
      - ./server:/app/server
      - /app/server/node_modules

After that I no longer got the "Can't find module" error
Still not sure what the impact of this is though