Dockerizing a Node.js application [2024 revised]

For this tutorial, I will assume you are starting a brand new Node.js application. If you already have a Node.js application you want to Dockerize, head over to Step 3.

*Before starting this tutorial, please make sure you have Docker downloaded.

Step 1

Initialize a new node.js app with

npm init 

This will give you a package.json file that looks something like this

// package-lock.json { "name": "sample_app", "version": "1.0.0", "description": "My First Dockerized Codebase", "author": "Your Name", "main": "app.js", "scripts": { "start": "node app.js" }, "dependencies": { "express": "^4.17.1" } } 

then run npm i (previously npm install) which will generate a package-lock.json.

Step 2

Next, we will create an app.js file

// app.js const express = require('express'); const app = express(); const PORT = [Your-port-here]; app.get('/', (req, res) => { res.send('Hello World'); }); app.listen(PORT, '0.0.0.0' () => { console.log('Server listening on Port ${PORT}'); }); 

Step 3

Here comes the fun part...
First, create a Dockerfile

touch Dockerfile 

Inside the Dockerfile, you will need to define the following:

# you can find your node version with: node --version FROM node:15 # Create app directory WORKDIR /app # Install app dependencies COPY package*.json ./ # Install dependecies RUN npm install # Bundle app COPY . . # Define your port EXPOSE 3000 # Tell Docker how to run your app CMD [ "node", "app.js" ] 

Step 4

Additional files are needed for Docker to successfully build your app.

.dockerignore

node_modules/ # anything else you want for Docker to ignore 

docker-compose.yml

version: '3.7' # you can find yours with python --version services: web: image: [your-image-name] build: . command: node app.js ports: - "4040:4040" volumes: - ./[your-image-name]/app - /app/node_modules depends_on: - mongodb mongodb: image: "mongo" ports: - "27017:27017" 

Step 5

Now that we have all the files, we can build and run the container.

Build a Docker container
docker build -t [your-app-name] .

Run the Docker container
docker run -it -p 3000:3000 [your-app-name]

Congratulations 🥳
If you have made it this far, you have successfully Dockerized your Node.js app.

Addition Docker Commands

docker ps
Check for running containers

docker-compose run [app-name] npm run migrate
Run migration and create table

docker pull
Pulls an image or a repository from a registry