Combining ADD and VOLUME on a nodejs Dockerfile

Question

I have a node project. My scripts section of package.json looks like this:

"scripts": {
 "postinstall": "gulp",
 "start": "node index.js",
 "test": "node ./node_modules/mocha/bin/mocha test"
},

My Dockerfile looks like this

FROM node:6.11-alpine
RUN mkdir -p /code
ADD . /code
WORKDIR /code
VOLUME /code
RUN npm install -g -s --no-progress yarn && \
 yarn && \
 yarn run test && \
 yarn cache clean

My docker-compose.yml looks like this:

version: "3"
services:
 web:
 build: .
 volumes:
 - .:/code
 command: "npm start"
 ports:
 - "8080:8080"
 networks:
 - internal
networks:
 internal:

This combination of ADD and VOLUME seems to give me what I need in terms of the javascript being there during the build stage and changes getting picked up in real time. However, I'm scared I'm doing something terribly wrong.

Answer 1

This Dockerfile should contain:

FROM node:6.11-alpine
COPY . /code
WORKDIR /code
RUN npm install -g -s --no-progress yarn && \
 yarn && \
 yarn run test && \
 yarn cache clean
EXPOSE 8080
CMD ["npm", "start"]

COPY copies your current directory to /code for building the final image (that holds compiled code normally).

In your docker-compose.yml, mounting a volume is used for your dev purposes, so that the files modified replace the ones on your image.

version: "3"
services:
 web:
 build: .
 volumes:
 - .:/code
 command: "npm run start:dev"
 ports:
 - "8080:8080"
 networks:
 - internal
networks:
 internal: