In this article i will show you how to dockerize a nodejs application

Part 1: Creating Node.js application

Usually, when I start a new Node.js project I use npm to generate my initial project.

npm init

When I was asked for the details of the application (name, version, etc.), just enter default values.

Then, Npm will create a package.json that will hold the dependencies of the app. Let’s add the Express Framework as the first dependency

$ npm install express --save

The file should look like this now:

{  
  "name": "helloworld",  
  "version": "1.0.0",  
  "description": "",  
  "main": "index.js",  
  "scripts": {  
    "test": "echo \"Error: no test specified\" && exit 1"  
  },  
  "author": "",  
  "license": "ISC",  
  "dependencies": {  
    "express": "^4.15.2"  
  }  
}

Next, everything has installed, we can create an index.js file with a simple HTTP server that will serve our Hello World website:

var express = require('express')
var app = express()

var port = 3000

app.get("/", function(req. res){
res.send("Hello World")
});

app.listen(port, function(){
console.log("Server started on port 3000")
}}

Now the application is ready to launch:

$ node index.js

Part 2: Dockerizing Node.js application

Let’s add Dockerfile to the directory with our application:

FROM node:latest

WORKDIR /app

COPY ..
RUN npm install

EXPOSE 3000

ENTRYPOINT ["node", "index.js"]

now we can build our Docker image

docker build -t {DOCKER_PROFILE_USERNAME}/node:latest .

Then, view our docker images use this command

docker images

now run docker container

`docker run -p 3000:3000` {DOCKER\_PROFILE\_USERNAME}/node

Surf to http://localhost:3000/ to see it running.