umahanish/demo-jenkins-maven-project

jenkins-maven-project

Building Jenkins Pipelines on Amazon Linux 2 AWS EC2 Instance

        Configuring Jenkins Pipeline with GitHub Webhook to Build the a Java Maven Project

• To build the java maven project with Jenkins pipeline using the Jenkinsfile and GitHub Webhook. To accomplish this task, we need;

  • a java code to build

  • a java environment to run the build stages on the java code

  • a maven environment to run the build stages on the java code

  • a Jenkinsfile configured for an automated build on our repo

• Create a public project repository demo-jenkins-maven-project on umapathy GitHub account.

• Clone the jenkins-maven-project repository on local computer.

-Copy the files from my repository(https://github.com/gulec2000/jenkins-maven-project/tree/main/hello-app) hello-app and paste under the jenkins-maven-project your GitHub repo folder.

• Go to the Jenkins dashboard and click on New Item to create a pipeline.

• Enter pipeline-with-jenkinsfile-and-webhook-for-maven-project then select Pipeline and click OK.

• Enter Simple pipeline configured with Jenkinsfile and GitHub Webhook for Maven project in the description field.

• Put a checkmark on GitHub Project under General section, enter URL of the project repository.

https://github.com/gulec2000/jenkins-maven-project.git

• Put a checkmark on GitHub hook trigger for GITScm polling under Build Triggers section.

• Go to the jenkins-maven-project repository page and click on Settings.

• Click on the Webhooks on the left hand menu, and then click on Add webhook.

• Copy the Jenkins URL from the AWS Management Console, paste it into Payload URL field, add /github-webhook/ at the end of URL, and click on Add webhook.

http://ec2-54-144-151-76.compute-1.amazonaws.com:8080/github-webhook/

- Go to the `Pipeline` section, and select `Pipeline script from SCM` in the `Definition` field.

- Select `Git` in the `SCM` field.

- Enter URL of the project repository, and let others be default.

```text
https://github.com/gulec2000/jenkins-maven-project.git

• Click apply and save. Note that the script Jenkinsfile should be placed under root folder of repo.

Java Installation

- sudo yum update -y
- sudo amazon-linux-extras install java-openjdk11 -y
- sudo yum install java-devel 

Maven Settings

• 'Maven' Installation on 'ec2 Instance' and setting uo the environment

- cd /opt
- wget https://www-eu.apache.org/dist/maven/maven-3/3.6.3/binaries/apache-maven-3.6.3-bin.tar.gz
- sudo tar xzf apache-maven-3.6.3-bin.tar.gz
- sudo ln -s apache-maven-3.6.3 maven
- sudo echo 'export M2_HOME=/opt/maven' >> /etc/profile.d/maven.sh
- sudo echo 'export PATH=${M2_HOME}/bin:${PATH}' >> /etc/profile.d/maven.sh
- source /etc/profile.d/maven.sh

GIT installation on 'ec2 instance'

 - sudo yum install git -y

Open Jenkins GUI on web browser

• Setting System Maven Path for default usage

- Go to `Manage Jenkins`
  - Select `Configure System`
  - Find `Environment variables` part,
  - Click `Add`
    - for `Name`, enter `PATH+EXTRA` 
    - for `Value`, enter `/opt/maven/bin`

• Setting a 'specific Maven Release' in Jenkins for usage

- Go to the `Global Tool Configuration`

- To the bottom, `Maven` section
  - Give a name such as `maven-3.6.3`
  - Select `install automatically`
  - `Install from Apache` version `3.6.3`

• Since the Jenkins Server would be running on Docker Machine, we could leverage from docker image of maven to setup the java and maven environment.

• Create a Jenkinsfile with the following pipeline script. This is for 'Docker image'

pipeline {
    agent {
        docker {
            image 'maven:3-openjdk-8'
            args '-v /root/.m2:/root/.m2'
        }
    }
    stages {
        stage('Build') {
            steps {
                sh 'mvn -B -DskipTests clean package'
            }
        }
        stage('Test') {
            steps {
                sh 'mvn test'
            }
            post {
                always {
                    junit 'target/surefire-reports/*.xml'
                }
            }
        }
        stage('Deliver') {
            steps {
                sh 'chmod +x deliver-script.sh'
                sh './deliver-script.sh'
            }
        }
    }
}

• For 'native structured Jenkins Server'

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'mvn -f hello-app/pom.xml -B -DskipTests clean package'
            }
            post {
                success {
                    echo "Now Archiving the Artifacts....."
                    archiveArtifacts artifacts: '**/*.jar'
                }
            }
        }
        stage('Test') {
            steps {
                sh 'mvn -f hello-app/pom.xml test'
            }
            post {
                always {
                    junit 'hello-app/target/surefire-reports/*.xml'
                }
            }
        }
    }
}

• Commit and push the changes to the remote repo on GitHub.

git add .
git commit -m 'added jenkinsfile and maven project'
git push

• Observe the new built triggered with git push command on the Jenkins project page.

• Explain the role of the docker image of maven, Jenkinsfile and GitHub Webhook in this automation.