Dockerfile: Dockerize A Node.js App

A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image.

Docker Image is an executable package of software that includes everything needed to run an application.

A Container is a runtime instance of an image. Containers make development and deployment more efficient since they contain all the dependencies and parameters needed for the application it runs completely isolated from the host environment.

Steps To Dockerize An App

Create your app.
Create a file named Dockerfile.
Add instructions in Dockerfile.
Build Dockerfile to create an image.
Run the image to create a container.

Dockerize A Node App

src/server.js

const express = require("express");
const app = express();

app.get("/", (req, res) => {
  res.send("Dockerizing a Node.js application here!");
});

app.listen(3000, function () {
  console.log("App listening on port 3000");
});

package.json

{
  "name": "my-app",
  "version": "1.0",
  "dependencies": {
    "express": "4.18.2"
  }
}

Dockerfile

FROM node:19-alpine

COPY package.json /app/
COPY src /app/

WORKDIR /app

RUN npm install

CMD ["node", "server.js"]

Build The Dockerfile To Create Image

docker build -t node-app:1.0 .

Run Container From The node-app:1.0 Image

docker run -d -p 3000:3000 node-app:1.0

The port defined here is 3000. So navigate to http://localhost:3000 and see the application working!