A Jenkinsfile describing the build process of a Angular4 & Spring Boot application

Jenkinsfile_Angular_SpringBoot.groovy

pipeline {

    agent {
        label 'BUILD' //Executed on agents with this label
    }

    triggers {
        pollSCM('* * * * *') //Polls every minute. If your git repo supports web-hooks this is not necessary.
    }

    environment {
        NO_CHROME_OPTS = "TRUE" //Environment variables
    }

    options {
        disableConcurrentBuilds()
    }

    stages {
        stage('Checkout') {
            steps {
                checkout scm //Checks out the SCM where the Jenkinsfile is located
                addJFrogCredentialsToGradlePropertiesFile() //custom groovy method
            }
        }
        stage('Frontend Static Code Analysis') { //stages are displayed in Jenkins UI
            steps {
                sshagent(['git']) { //provide SSH key for a git repo from another project necessary for the build, "git" is configured in Jenkins
                    script {
                        try {
                            sh './gradlew tslint --no-daemon'
                        } finally { //make checkstyle results accessible to user
                            checkstyle canComputeNew: false, defaultEncoding: '', healthy: '', pattern: 'frontend/tslint-result.xml', unHealthy: ''
                        }
                    }
                }
            }
        }
        stage('Frontend Unit Tests') {
            steps {
                sshagent(['git']) {
                    script {
                        try {
                            sh './gradlew cleanFrontendTest --no-daemon'
                            sh './gradlew frontendUnitTest --no-daemon'
                        } finally {
                            junit 'frontend/test/karma-result.xml' //make junit report accessible to user
                        }
                    }
                }
            }
        }
        stage('Unit & Integration Tests') {
            steps {
                script {
                    try {
                        sh './gradlew clean test --no-daemon'
                    } finally {
                        junit '**/build/test-results/test/*.xml'
                    }
                }
            }
        }
        stage('End 2 End Tests') {
            steps {
                script {
                    try {
                        sh './gradlew e2e --no-daemon'
                    } finally {
                        junit '**/e2e-results/junit-formatted/*.xml'
                        publishHTML([allowMissing: false, alwaysLinkToLastBuild: false, keepAll: false, reportDir: 'frontend/test/e2e-results/html-formatted/', reportFiles: 'htmlReport.html', reportName: 'End 2 End Test Report', reportTitles: ''])
                    } //make the HTML results of the e2e tests available to user
                }
            }
        }
        stage('Publish Artifact') {
            steps {
                sh './gradlew publish --no-daemon'
            }
        }
        stage('SonarQube Analysis') {
            steps {
                script {
                    scannerHome = tool 'sonarscanner'
                }
                withSonarQubeEnv('sonar') {
                    sh "${scannerHome}/bin/sonar-scanner"
                }
            }
        }
    }
    post {
        always { //If the build fails, send an email to the last person(s) to commit since the last green build
            step([$class                  : 'Mailer',
                  notifyEveryUnstableBuild: true,
                  recipients              : [emailextrecipients([[$class: 'CulpritsRecipientProvider'], [$class: 'RequesterRecipientProvider']])].join(' ')])
        }
    }
}

private void addJFrogCredentialsToGradlePropertiesFile() { //Write jFrog credentials to gradle.properties file
    withCredentials([usernamePassword(credentialsId: 'jFrog', usernameVariable: 'JFROG_USER', passwordVariable: 'JFROG_PASSWORD')]) {
        sh "rm -f ~/.gradle/gradle.properties"
        sh "echo jFrogUser=$JFROG_USER >> ~/.gradle/gradle.properties"
        sh "echo jFrogPassword=$JFROG_PASSWORD >> ~/.gradle/gradle.properties"
    }
}