Dockerizing NodeJS – keeping node modules - node.js

Question

I have an NodeJS express app that I want to dockerize. For that I created a Dockerfile:
FROM node:18 AS server
ENV NODE_ENV=production
WORKDIR /app
COPY package*.json /
RUN npm ci
COPY . .
I also have a .dockerignore file:
node_modules/
client/node_modules/
Dockerfile
docker-compose.yml
.git
.gitignore
.dockerignore
.env
All is run with a help of docker-compose.yml:
version: '3.8'
services:
app:
container_name: my-app
image: my-org/my-app
build:
context: .
dockerfile: Dockerfile
command: node index.js
ports:
- "3030:3030"
environment:
HELLO: world
env_file:
- .env
When I run the Dockerfile commands in this order, the COPY . . seems to remove the node_modules from the image, that are created with npm ci that runs beforehand. I've tried it with first running COPY . . and then npm ci and node_modules stays in the image.
My question is – is it better to run npm ci before COPY . ., and if the answer is yes, then how can I make the node_modules stay?

Answer 1

I had a similar problem and used for that a "build container".
You ignored the node_modules folder in your .dockerignore. Therfore it does not get copied in your image.
# The instructions for the first stage
FROM node:16-alpine as builder
ARG NODE_ENV=production
ENV NODE_ENV=${NODE_ENV}
RUN apk --no-cache add python3 make g++
COPY ./package*.json ./
RUN npm install
# ------------------------------------
# The instructions for second stage
FROM node:16-alpine
WORKDIR /opt/OpenHaus/backend
COPY --from=builder node_modules node_modules
RUN apk --no-cache add openssl
COPY . ./
#COPY ./package.json ./
#ENV HTTP_PORT=8080
ENV NODE_ENV=production
#ENV DB_HOST=10.0.0.1
#EXPOSE 8080
CMD ["node", "index.js"]
With that the dependencies are "build" and copied from the build container inside your node.js image.
More to read:
https://medium.com/#kahana.hagai/docker-compose-with-node-js-and-mongodb-dbdadab5ce0a
https://dev.to/alex_barashkov/using-docker-for-nodejs-in-development-and-production-3cgp