I have a Django application for the backend and a Vue application for the frontend. The app works 100% on my local machine. I am trying to dockerize the application so I can deploy it on a VPS just for someone to look at.

The front end starts up when I run docker compose up but the back end gives me the same error every time:

python3: can't open file '/app/manage.py': [Errno 2] No such file or directory

My directory structure is as follows:

back (directory)
... (django apps directories)
-- manage.py
-- Dockerfile
-- requirements.txt

front (directory)
... (vue directories)
-- Dockerfile
-- package.json
-- vite.config.js
-- index.html

Here is my Dockerfile for the backend:

FROM python:3.10

WORKDIR /app

COPY requirements.txt .

RUN pip install --no-cache-dir -r requirements.txt

COPY . back

EXPOSE 8000

CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]

Here is my Dockerfile for the front end:

FROM node:20-alpine3.17

WORKDIR /app

COPY package.json /app/
RUN npm install 

COPY . front/

EXPOSE 8080

CMD ["npm", "run", "dev:docker"]

and here is my docker-compose.yml file:

version: "1.1"

services:
  db:
    image: postgres:15-alpine
    volumes:
      - ./db:/var/lib/postgresql/data
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=postgres
      - POSTGRES_DB=postgres
  back:
    build: ./back
    ports:
      - "8000:8000"
    volumes:
      - ./:/back
    env_file: ./back/.env
    command: python3 manage.py runserver 0.0.0.0:8000
    depends_on:
      - db
    restart: on-failure
  front:
    build: ./front
    ports:
      - "8080:8080"
    volumes:
      - ../front/src:/front/src
    environment:
      - CHOKIDAR_USEPOLLING=true
    command: npm run dev
    depends_on:
      - back

So I have two questions please:

1. Why am I getting the cannot find file error?
2. When I deploy the working Docker image on the VPS how do I make it available on port 80 so if I point my domain to the VPS that I will see the complete site?

Thanks for any help.