Initialize Your Repository

npm init -y

Install Dependencies

Express version 5 now supports asynchronous route handlers. While this version is still in beta, we can expect a stable release soon.

npm i [email protected]

For your reference, below is the suggested folder structure for the project.

Creating an Express Application

Within the src directory, create an index.js file with the following content:

const express = require("express");

const app = express();

const port = 3000;

app.get("/", async (req, res) => {

res.send("Hello Medium!");

});

app.listen(port, () => {

console.log(Your app is running on http://localhost:${port});

});

We can also enhance the package.json file to streamline our development process. To avoid the need to restart the application manually each time, we can enable watch mode. For this, we need to use nodemon in earlier versions:

{

"name": "medium-app",

"version": "1.0.0",

"description": "",

"main": "./src/index.js",

"scripts": {

"start": "node ./src/index.js",

"start:dev": "node --watch ./src/index.js"

},

"keywords": [],

"author": "",

"license": "ISC",

"dependencies": {

"express": "^5.0.0-beta.3"

}

}

At this point, your application should function correctly.

Running the Application

With Docker, we can assign a unique port for each container. This needs to be reflected in our code:

const express = require("express");

if (!process.env.PORT) {

throw new Error("Please specify a port");

}

const app = express();

const port = process.env.PORT;

app.get("/", async (req, res) => {

res.send("Hello Medium!");

});

app.listen(port, () => {

console.log(Your app is running on http://localhost:${port});

});

Creating the Dockerfile

Next, we will create a Dockerfile in the root directory. In production scenarios, you can use npm ci --omit=dev to install dependencies while excluding development packages:

FROM node:21.7-alpine

WORKDIR /usr/src/app

COPY package*.json ./

RUN npm ci --omit=dev

COPY ./src ./src

CMD npm start

Don’t forget to establish a .dockerignore file. If your Docker builds are taking longer than expected, it could be because they are processing too many files. The .dockerignore file allows you to specify which files and directories should be excluded from the build process:

.idea

.git

node_modules

Building the Docker Image

To create your Docker image, run the following command:

docker build -t medium-docker --file Dockerfile .

Running the Docker Container

Start your application with:

docker run -d -p 3000:3000 -e PORT=3000 medium-docker

Cleaning Up

To manage your containers, first, list them to find the ID of the running container:

docker container list

Next, you can stop and remove the container with the following commands:

docker stop <container_id>

docker rm <container_id>

Your application should now be running smoothly within Docker.

Thank you for reading this guide! I hope you found it informative. If you have any feedback or questions, please feel free to reach out.