If you plan to run your node.js application, nothing could be better than running on the docker and safely storing it on Dockerhub.

Running an application on docker is a huge benefit because of its light-weighted technology and security. Docker images are stored safely on the dockerhub

In this tutorial, you will learn how to create a docker image for node.js applications and push it to dockerhub using the Jenkins pipeline.

Let’s get started.

Table of Content

1. What is Jenkins Pipeline?
2. What is Jenkinsfile?
3. What is node.js server-side javascript?
4. Prerequisites
5. How to Install node.js and node.js framework on ubuntu machine
6. Creating Node.js Application
7. How to create dockerfile for Node.js application
8. Pushing all the code to GIT Repository: Git Push
9. Creating Jenkinsfile to run docker image of Node.js application
10. Configure Jenkins to Deploy Node.js Docker Image and Push to Dockerhub
11. Conclusion

What is Jenkins Pipeline?

Jenkins Pipeline uses a group of plugins that help deliver a complete continuous delivery pipeline starting from building the code till deployment of the software right up to the customer.

Jenkins Pipeline plugin is automatically installed while installing the Jenkins with suggested plugins and allows you to write complex operations and code deployment as code using DSL language ( Domain-specific language).

Related: the-ultimate-guide-getting-started-with-Jenkins-pipeline

What is Jenkinsfile?

Jenkins Pipelines uses a text file called Jenkinsfile, which is checked into the repository. You define each stage and steps that need to be executed, such as building and compiling code to deploy in respective environments.

Jenkinsfile allows you to define steps in code format, which is easier and gives more ability to review. In case Jenkins stops, you can still continue to write Jenkinsfile. It can hold, wait, approve, stop Jenkins job and many other functionalities.

What is node.js server-side javascript?

JavaScript is a language used with other languages to create a web page add some dynamic features such as rollover or graphics, and Node.js is an open-source JavaScript runtime environment.

Node.js performs well as it contains only a single process without wasting much memory, CPU and never blocks any threads or processes and furthermore allows multiple connections simultaneously.

Node.js allows JavaScript developers to create apps in the front and backend.

Prerequisites

• You must have ubuntu machine preferably 18.04 version + and if you don’t have any machine you can create a ec2 instance on AWS account
• Docker and Jenkins must be installed on ubuntu machine.
• Make sure you have git hub account and a repository created . If you don’t have follow here

How to Install node.js and node.js framework on ubuntu machine

Now that you know what is node.js and what are benefits of having node.js. In this section, let’s dive into how to Install node.js and node.js frameworks on ubuntu machines.

• Log in to the Ubuntu machine using your favorite SSH client.

• Now, create a folder named nodejs-jenkins under opt directory in the ubuntu machine.

cd /opt
mkdir nodejs-jenkins
cd nodejs-jenkins

• Now install node.js on ubuntu machine using the below command.

sudo apt install nodejs

• Next, Install node.js package manager. Installing node.js package manager allows to install modules node_modules inside the same directory.

sudo apt install npm

• Further install Nodejs express Web Framework and initialize it. This command will generate package.json file containing the project, all the dependencies and metadata details that will be used to create a project and further application.

npm init

• Further, add one dependency which is required by node.js application.

npm install express --save

Creating Node.js Application

Now that you have successfully installed the node.js application and framework required to create a node.js application. Let’s create a node.js application.

Assuming you are still logged into the ubuntu machine.

• Firstly, create a file named main.js in the /opt/nodejs-jenkins directory and copy/paste the below code.

var express = require('express')    //Load express module with `require` directive
var app = express() 

//Define request response in root URL (/)
app.get('/', function (req, res) {
  res.send('Hello Welcome to Automateinfra.com')
})
app.listen(8081, function () {
  console.log('app listening on port 8081!')
})

How to create dockerfile for Node.js application

Previously you created a node.js application, which is great, but to deploy node.js on docker, you will need to create a dockerfile. Docker file creates customized docker images on top of docker images.

After creating the dockerfile, you can use the docker build command to create a new customized docker image.

Let’s jump in and create a dockerfile for the node.js application.

• Create a file named dockerfile in the same /opt/nodejs-jenkins directory and copy/paste the below content.

FROM node:7              # Sets the base image
RUN mkdir -p /app
WORKDIR /app             # Sets the working directory in the container
COPY package.json /app   # copy the dependencies file to the working directory
RUN npm install          # Install dependencies
COPY . /app       # Copy the content of the local src directory to the working directory
EXPOSE 4200
CMD ["npm", "run", "start"]

• Next, to create a node.js docker image using above dockerfile run the below command on ubuntu machine.

docker build .

Pushing all the code to GIT Repository: Git Push

Earlier, you created the node.js application and manually built the docker image to confirm that your code is absolutely fine and works. Let’s push all the files and code in the Git repository using various commands so that later Jenkins can use these files and build the application.

• Now your directory /opt/nodejs-jenkins should have look as below.

• Initialize a new repository in the same directory /opt/nodejs-jenkins by running git init command.

git init

• Add all the file in git repository using the below command in the same directory /opt/nodejs-jenkins

git add .

• Now, check the status of git repository with below command. If there are any errors they will appear else you are good to go to the next step.

git status

• Commit your changes in git repository using the git commit command in the same directory /opt/nodejs-jenkins

 git commit -m "MY FIRST COMMIT"

• Add the remote repository that you already had as a origin by running git remote add command.

git remote add origin https://github.com/Engineercloud/nodejs-jenkins.git

• Finally push the changes in the remote branch . Once prompted specify your credentials.

git push -u origin master

• Now, verify the code on github by navigating to the repository link.

Creating Jenkinsfile to run docker image of Node.js application

Let’s quickly jump into the creation of Jenkinsfile to run docker image of Node.js application to deploy an application using Jenkins.

• Create a file named Jenkinsfile in the same /opt/nodejs-jenkins directory and copy/paste the below content. Make sure to change the sXXXXXXX410/dockerdemo as per you’re dockerhub username and repository name.

node {
     def app 
     stage('clone repository') {
      checkout scm  
    }
     stage('Build docker Image'){
      app = docker.build("sXXXXX410/dockerdemo")
    }
     stage('Test Image'){
       app.inside {
         sh 'echo "TEST PASSED"' 
      }  
    }
     stage('Push Image'){
       docker.withRegistry('https://registry.hub.docker.com', 'git') {            
       app.push("${env.BUILD_NUMBER}")            
       app.push("latest")   
   }
}

• Now push the Jenkinsfile as well in github in the same repository that you used earlier. Now, your repository should look something like below.

Configure Jenkins to Deploy Node.js Docker Image and Push to Dockerhub

Now that you have all the code, including Jenkinsfile, in the Github repository and deploy the node.js application on docker using Jenkinsfile, you need to create a Jenkins Job. Let’s configure Jenkins by creating a new multi-branch pipeline Jenkins Job.

• Create a new multibranch pipeline Jenkins Job named nodejs-image-dockerhub by clicking on new item and selecting multibranch pipeline on the Dashboard.

• Now click on nodejs-image-dockerhub job and click on configure it with git URL and then hit save.

• To connect to dockerhub you would need to add dockerhub credentials by clicking on the Dashboard ➔ Manage Jenkins ➔ Manage credentials ➔ click on global ➔ Add credentials.

• Next, on Jenkins server add Jenkins user in the docker group so that Jenkins user has access to run docker commands.

sudo groupadd docker
sudo usermod -a -G docker jenkins
service docker restart

• Further, make sure Jenkins users has sudo permissions by running below commands.

sudo vi  /etc/sudoers
jenkins ALL=(ALL) NOPASSWD: ALL

• Now you are ready to run your first jenkins job. click on scan Multibranch pipeline job that will scan your branches in the repository. Then click on Branch and then click on Build Now.

• The Jenkins job is completed successfully. Lets verify if Docker image has been successfully pushed to dockerhub by visiting Dockerhub repository.

Conclusion

In this tutorial, you learned what the Jenkins pipeline is, node.js is, and how to create a dockerfile, Jenkins file, and node.js application. Finally, you pushed the docker image to dockerhub using Jenkins.

So now you know how to deploy the node.js application on docker; which application do you plan to deploy next?