Containerize a Node.js application

Prerequisites

You have installed the latest version of Docker Desktop.
You have a git clientopen_in_new. The examples in this section use a command-line based git client, but you can use any client.

Overview

This section walks you through containerizing and running a Node.js application.

Get the sample application

Clone the sample application to use with this guide. Open a terminal, change directory to a directory that you want to work in, and run the following command to clone the repository:

$ git clone https://github.com/docker/docker-nodejs-sample

Test the application without Docker (optional)

You can test the application locally without Docker before you continue building and running the application with Docker. This section requires you to have Node.js 18 or later installed on your machine. Download and install Node.jsopen_in_new.

Open a terminal, change directory to the docker-nodejs-sample directory, and run the following command to install the packages.

$ npm install

When the packages have finished installing, run the following command to start the application.

$ node src/index.js

Open a browser and view the application at http://localhost:3000open_in_new. You should see a simple todo application.

In the terminal, press ctrl+c to stop the application.

Initialize Docker assets

Now that you have an application, you can use docker init to create the necessary Docker assets to containerize your application. Inside the docker-nodejs-sample directory, run the docker init command in a terminal. Refer to the following example to answer the prompts from docker init.

$ docker init
Welcome to the Docker Init CLI!

This utility will walk you through creating the following files with sensible defaults for your project:
  - .dockerignore
  - Dockerfile
  - compose.yaml

Let's get started!

? What application platform does your project use? Node
? What version of Node do you want to use? 18.0.0
? Which package manager do you want to use? npm
? What command do you want to use to start the app: node src/index.js
? What port does your server listen on? 3000

You should now have the following contents in your docker-nodejs-sample directory.

├── docker-nodejs-sample/
│ ├── spec/
│ ├── src/
│ ├── .dockerignore
│ ├── .gitignore
│ ├── compose.yaml
│ ├── Dockerfile
│ ├── package-lock.json
│ ├── package.json
│ └── README.md

To learn more about the files that docker init added, see the following:

Run the application

Inside the docker-nodejs-sample directory, run the following command in a terminal.

$ docker compose up --build

Open a browser and view the application at http://localhost:3000open_in_new. You should see a simple todo application.

In the terminal, press ctrl+c to stop the application.

Run the application in the background

You can run the application detached from the terminal by adding the -d option. Inside the docker-nodejs-sample directory, run the following command in a terminal.

$ docker compose up --build -d

Open a browser and view the application at http://localhost:3000open_in_new.

You should see a simple todo application.

In the terminal, run the following command to stop the application.

$ docker compose down

For more information about Compose commands, see the Compose CLI reference.

Summary

In this section, you learned how you can containerize and run your Node.js application using Docker.

Related information:

Next steps

In the next section, you'll learn how you can develop your application using containers.

Develop your application