Dockerfile - Build docker image for multiple Node.js app - node.js

Question

How do I run all my Node.js file in a single container?
app1.js running on port 1001
app2.js running on port 1002
app3.js running on port 1003
app4.js running on port 1004
Dockerfile
FROM node:latest
WORKDIR /rootfolder
COPY package.json ./
RUN npm install
COPY . .
RUN chmod +x /script.sh
RUN /script.sh
script.sh
#!/bin/sh
node ./app1.js
node ./app2.js
node ./app3.js
node ./app4.js

Answer 1

You would almost always run these in separate containers. You're allowed to run multiple containers from the same image, you can override the default command for an image when you start it up, and you can remap the ports an application uses when you start it.
In your Dockerfile, delete the RUN /script.sh line at the end. (That will try to start the servers during the image build, which you don't want.) Now you can build and run containers:
docker build -t myapp . # build the image
docker network create mynet # create a Docker network
docker run \ # run the first container...
-d \ # in the background
--net mynet \ # on that network
--name app1 \ # with a known name
-p 1001:3000 \ # publishing a port
myapp \ # from this image
node ./app1.js # running this command
docker run \
-d \
--net mynet \
--name app2 \
-p 1002:3000 \
myapp \
node ./app2.js
(I've assumed all of the scripts listen on the default Express port 3000, which is the second port number in the -p options.)
Docker Compose is a useful tool for running multiple containers together and can replicate this functionality. A docker-compose.yml file matching this setup would look like:
version: '3.8'
services:
app1:
build: .
ports:
- 1001:3000
command: node ./app1.js
app2:
build: .
ports:
- 1002:3000
command: node ./app2.js
Compose will create a Docker network on its own, and take responsibility for naming the images and containers. docker-compose up will start all of the services in parallel.

Answer 2

You need to expose the ports first using:
EXPOSE 1001
...
EXPOSE 1004
in your dockerfile and later run the container using the -p parameter as with -p 1501:1001
to expose -for example- the port 1501 of the host to work as the 1001 port of the container.
ref: https://docs.docker.com/engine/reference/commandline/run/
However, it is suggested to minimize the number of programs to be run from a docker container. So, you might like to have a container for each of your js scripts.
Yet, Nothing stops you from using:
docker exec -it yourDockerMachineName bash
several times where you can use each of your node cmds.

Answer 3

What you are trying to achieve is considered to be an anti-pattern.
Conversely, having in mind the single-responsibility-principle when building up the stacks of your apps will give you better leverages to manage, monitor, change your app etc.
This article from the official documentation explains when you might want to do this.
If you want to manage multiple containers as a whole, having one Dockerfile for each js, combined with a docker-compose file to bring up all the containers at once on different ports might answer your question. Here is a minimal example:
docker-compose.yml
version: '3.7'
services:
app1:
image: your-js-app-1-image
container_name: app-1
ports:
- '1001:3000'
app2:
image: your-js-app-2-image
container_name: app-2
ports:
- '1002:3000'

Answer 4

Ideally you should run each app on a separated container, if your applications are different. In the case they are equal and you want to run multiple instances on different ports
docker run -p <your_public_tcp_port_number>:3000 <image_name>
or a good docker-compose.yaml would suffice.
Technically you may want to run each different application on a different container and run multiple instances of the same application in order to make it easy to version each of your app on a newer independent image. It will allows you to independently stop, deploy and start your apps on the production environment.