在docker中使node_modules保持最新

Question

I'm working with a team on a repo built in Docker and Node. When someone else installs node packages, I git pull those changes to package.json and package-lock.json .

I can't just run docker-compose build and then docker-compose up , though, to install these new node packages. I have to first docker-compose down -v . This is because we're using a volume to store the node modules. We're not tied to this, and frankly would rather just store the modules in a docker image layer. But then, when we bind the app volume ( - .:/app in docker-compose.yml ), the node_modules folder in the image is shadowed.

It feels like we're taking the wrong approach to this, but this seems to be what the generally accepted practice is. Our setup is based on " Lessons from Building a Node App in Docker "

Our Dockerfile :

FROM node:8.4.0
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm install --loglevel=error --progess=false
COPY . /app/

Our docker-compose.yml :

---
version: '2.1'

services:
  main:
    build:
      context: .
    volumes:
      - .:/app
      - /app/node_modules
    container_name: main
    command: ['node', 'index.js']

My understanding of the issue is that, in the docker-compose.yml file, The volume - /app/node_modules creates a volume that copies the node modules from inside the image layer into a volume, meaning that when we build the app again with a different package.json , the image is updated but not the volume. down ing the volume forces it to re-copy from the updated image node_modules , which is why that works. Please let me know if my understanding is incorrect :)

We're running in AWS ECS, so unfortunately we can only use docker features available in 17.03.2-ce (no multi-stage docker files for now).

Answer 1

Looks like you map the current folder to /app in container. I would erase ./node_modules if it exists in current folder, before doing docker-compose.