How to Create a Docker container for your NodeJs app 🐳

If you’ve ever wondered how to Dockerize and run your NodeJs app as a container, and never ever done it then you’ve landed at the right place

What you’ll be building

A NodeJs app Running on a Docker container on your local machine

Step 1

Initialising a NodeJs app with express

1. cd into the folder you want to make your NodeJs app
2. Run npm init -y

This will generate a package.json file for you

3. Now to install Express type 👇🏻

npm i express

and Press Enter or Return key

Express will now be installed as a dependency in your project

4. Now create a index.js file in your app directory with the following code

5. Your NodeJs express app is now ready. To run the app Open Terminal and cd into your project directory and type

node index.js

If you see server running message printed on terminal, tada your node app is now ready

Step 2

Time to dockerize it

In your project Directory create a file named Dockerfile without any extension and save it

Copy 👇🏻 these lines in Dockerfile

• FROM node:alpine this is the very first line of any Dockerfile and specifies the base image you are using to create your docker image, in our case we are using node:alpine
• WORKDIR /var/www this line specifies our current working directory. In our case we want our project to be in /var/www , so we are saying docker that make our current working directory to /var/www
• COPY package.json . A self explanatory step we’re just simply copying our package.json file to our current working directory
• RUN npm install This step installs all our project’s dependencies in the docker container
• COPY . . In the earlier step we copied only package.json to install dependencies only. Now as we have all the dependencies installed, we are copying all of our project’s files in to the container
• EXPOSE 80 This step exposes Port 80 of our container for outer world to access
• CMD [“node”, “index.js”] And finally we’re running the app by running the node command

Build the Docker Image

we’re now one step closer to dockerizing our NodeJs app.

we have everything ready now. The last step that is left is just Build our Docker image from the Dockerfile and run it.

To build the image open your Terminal and cd into project folder

and run docker build -t image .

docker will now start building your image from Dockerfile

you’ll see a screen like 👇🏻 once it will finish building.

FINALLY it’s time to run our Docker container

Now run commanddocker run -p 80:80 image and you’ll see message server running

Now go to your web browser and type localhost and press Enter or Return

Congrats Your NodeJs project is Now dockerized 🎉🥳