An efficient Dockerfile to build an image with NestJS with just the production dependencies

Dockerfile

FROM node:16.17-alpine as builder

WORKDIR /usr/src/app

ARG NODE_ENV=production
ENV NODE_ENV=${NODE_ENV}

COPY package*.json ./

RUN npm i -g @nestjs/cli \
    && npm install

COPY . .

RUN npm run build

FROM node:16.17-alpine as runtime

ARG NODE_ENV=production
ENV NODE_ENV=${NODE_ENV}

ARG NODE_PORT=8080
ENV NODE_PORT=${NODE_PORT}

WORKDIR /usr/src/app

COPY --from=builder /usr/src/app/node_modules ./node_modules
COPY --from=builder /usr/src/app/package*.json ./
COPY --from=builder /usr/src/app/dist ./dist

CMD ["npm", "run", "start:prod"]

Overview

Controlling dependencies in NodeJS can come in handy if used wisely. Most people don't take the time to analyze what the final size of a generated image is. They usually run an npm install, build the project and start the application. With that in mind, I decided to explore how to build an efficient Dockerfile so that, when building an image, only production dependencies enter the build. The example here is for a NestJS project and can be tweaked for other frameworks just adapting to your needs.

This is capable of halving the size of a Docker image!

The use in a docker-compose.yml is also interesting because in it we specify that we want the development dependencies (running in a local environment, of course).

Usage with docker-compose.yml

version: "3"

services:
  app:
    build:
      context: .
      args:
        NODE_ENV: development
    ports:
      - 8080:8080
    command: npm run start:dev
    volumes:
      - .:/usr/src/app
      - node_modules:/usr/src/app/node_modules
    environment:
      NODE_PORT: 8080

volumes:
  node_modules: