Node + Docker Compose: Development and production setup

Question

I'm looking for a solution to have both a development and a production environment in my project using docker, docker-compose and nodejs.

How do I approach this?

Basically what I want is a command to start my docker production environment, and a command to start my development environment (which could use nodemon for example).

Here is my Dockerfile

FROM node:13-alpine

RUN mkdir /app

WORKDIR /app

COPY . /app

RUN npm install

RUN npm run build

EXPOSE 1234

CMD ["npm", "run", "prod"] # <--- Have a possibility to run something like "npm run dev" here instead

docker-compose.yml

version: "3"
services:
    findus:
        build: .
        ports:
            - "1234:1234"
        links:
            - mongo
        container_name: myapp
    mongo:
        image: mongo
        restart: always
        ports:
            - "4444:4444"

package.json

// ...
    "scripts": {
        "build": "tsc",
        "dev": "nodemon source/index.ts",
        "prod": "node build/index.js"
    },
// ...

Answer 1

You can make use of entrypoint and pass the command to the docker container. Then you can use docker-compose inharitance to launch compose for the environment that you want and append command to the entrypoint.

Dockerfile :

FROM node:13-alpine

RUN mkdir /app

WORKDIR /app

COPY . /app

RUN npm install

RUN npm run build

EXPOSE 1234

ENTRYPOINT ["npm", "run"]

Main docker-compose.yml :

version: "3"
services:
    findus:
        build: .
        ports:
            - "1234:1234"
        links:
            - mongo
        container_name: myapp
    mongo:
        image: mongo
        restart: always
        ports:
            - "4444:4444"

And then have two docker-compose files to append the command passed to the image entry point. For development - docker-compose.dev.yml :

version: "3"
services:
    findus:
        command: dev

and docker-compose.prod.yml :

version: "3"
services:
    findus:
        command: prod

Then to launch dev environment :

docker-compose  -f docker-compose.yml -f docker-compose.dev.yml up    

and for prod environment :

docker-compose  -f docker-compose.yml -f docker-compose.prod.yml up   

So the command will be appended to the ENTRYPOINT instruction.

---

Also this approach could work with enviroment variables if you wanted to pass the command as environment variable. You can find more information in the docs.