Jenkins Shared Library - Vars

This directory contains reusable Groovy scripts for Jenkins pipelines. These scripts can be used to perform common tasks such as checking out Git repositories, building code, building Docker images and pushing Docker images.

Scripts

1. checkoutGitRepo.groovy

This script checks out a Git repository from a specified URL and branch.

Usage

checkoutGitRepo(String repoUrl, String branch = 'main')

Parameters

repoUrl: The URL of the Git repository. branch: The branch to checkout (default is main).

Example

checkoutGitRepo('https://github.com/username/repo.git', 'main')

2. buildCode.groovy

This script is used to build code using a specified build command.

Usage

buildCode(String buildCommand)

Parameters

buildCommand: The command to build the code (e.g., mvn clean install, npm install).

Example

buildCode('mvn clean install')

3. buildDockerImage.groovy

This script builds a Docker image using a specified Dockerfile path, image name, and image tag.

Usage

buildDockerImage(String dockerfilePath, String imageName, String imageTag)

Parameters

dockerfilePath: The path to the Dockerfile. imageName: The name of the Docker image. imageTag: The tag for the Docker image.

Example

buildDockerImage('Dockerfile', 'sample', 'latest')

4. pushDockerImage.groovy

This script tags and pushes a Docker image to a specified Docker repository URL.

Usage

pushDockerImage(String imageName, String imageTag, String dockerRepoUrl)

Parameters

imageName: The name of the Docker image. imageTag: The tag of the Docker image. dockerRepoUrl: The URL of the Docker repository.

Example

pushDockerImage('sample', 'latest', 'username/repo')

Example Jenkins Pipeline

Here is an example of how to use these scripts in a Jenkins pipeline where I used a public repo which contains a Spring Boot based Java web application:

@Library('my-shared-library') _

pipeline {
    agent any
    environment {
        DOCKER_HUB_CREDENTIALS = credentials('Dockerhub_cred')
    }

    stages {
        stage('Checkout') {
            steps {
                checkoutGitRepo('https://github.com/iam-veeramalla/Jenkins-Zero-To-Hero.git', 'main')
            }
        }
        stage('Build') {
            steps {
                dir('java-maven-sonar-argocd-helm-k8s/spring-boot-app') {
                    buildCode('mvn clean install')
                }
            }
        }
        stage('Build Docker Image') {
            steps {
                dir('java-maven-sonar-argocd-helm-k8s/spring-boot-app') {
                    buildDockerImage('Dockerfile', 'sample', 'latest')
                }
            }
        }
  
        stage('Push Docker Image') {
            steps {
                sh 'echo $DOCKER_HUB_CREDENTIALS_PSW | docker login -u $DOCKER_HUB_CREDENTIALS_USR --password-stdin'
                   pushDockerImage('sample', 'latest', 'rithin730/sample')
            }
        }
    }
}

Common Issues

Docker Permission Denied

If you encounter a permission denied error while trying to connect to the Docker daemon, ensure that the Jenkins user has the appropriate permissions. You may need to add the Jenkins user to the docker group:

sudo usermod -aG docker jenkins

Docker Hub Authentication

If you receive a denied: requested access to the resource is denied error when pushing a Docker image, ensure that your Jenkins instance is properly authenticated with Docker Hub. This can be done by configuring Docker credentials in Jenkins: