Build and Push Docker Images with Jenkins

In this guide we'll see how to build a Docker image and push it to a Docker registry using a Declarative Pipeline in Jenkins.

What you need:

• A Jenkins instance
• Docker Plugin: https://plugins.jenkins.io/docker-workflow
• A code repository with a Dockerfile

In our post we'll use a simple "Hello World!" (written in Node.JS) application as an example.

Steps of the pipeline:

1. Clone the source repository
2. Build the application
3. Build Docker image 
4. Push image to Docker registry

Source code.

Our application source code is organized as follows:

simple-nodejs-app
├── Dockerfile
├── index.js
└── package.json

The content of the Dockerfile is the following:

FROM node:alpine
ADD . /
USER node
EXPOSE 3000
CMD npm run start

We want to build an image called mynode:latest and push it to https://myregistry.

Credentials.

Create a credentials resource on Jenkins, to access the Docker registry:

In this example, we've named the credentials resource registrycredentials




How to build and push a Docker Image with Jenkins?

This table summarizes how to translate Docker commands in Jenkins pipeline instructions:




Docker command	Equivalent in Jenkins pipeline
docker build myregistry/mynode:latest	docker.build("myregistry/mynode:latest")
docker push myregistry/mynode:latest	withDockerRegistry(     credentialsId: 'registrycredentials',     url: "https://myregistry") {         docker_image.push("latest") }

Complete source code of the pipeline.

Now that we have all the resources, let's see the complete pipeline:

pipeline {
    agent any
    
    stages {
        
        stage('Clone sources') {
            steps {
                git credentialsId: 'mygitcredentials', branch: 'develop', url: 'https://git.mycompany.com/simple-node-js-app.git'
            }        
        }


        stage('Install npm packages') {
            steps {
                nodejs(nodeJSInstallationName: 'node13') {
                    sh 'npm i'
                    sh 'npm rebuild node-sass'
                }
            }
        }

        stage('Build app') {
            steps {
                nodejs(nodeJSInstallationName: 'node13') {
                    sh 'npm run build:dev'
                }
            }
        }

        stage("Build Docker image") {
            steps {
                script {
                    docker_image = docker.build("myregistry/mynode:latest")
                }
            }
        }

        stage("Push images") {
            steps {
                script {
               
                    withDockerRegistry(credentialsId: 'registrycredentials', url: "https://myregistry") {
                        docker_image.push("latest")
                    }
                }
            }
        }




If you want to learn more about Docker and Jenkins, visit our CICD and DevOps pages!