Environment Variables

pipeline {
    agent { label 'linux && docker' }

    // Pipeline-level environment variables — available in every stage
    environment {
        APP_NAME         = 'checkout-service'
        DOCKER_REGISTRY  = 'registry.acmecorp.com'
        DEPLOY_ENV       = 'staging'
        STAGING_URL      = 'https://checkout.staging.acmecorp.com'

        // Combine built-in Jenkins variables with your own
        // BUILD_NUMBER is injected by Jenkins automatically
        IMAGE_TAG        = "${APP_NAME}:${BUILD_NUMBER}"
        FULL_IMAGE       = "${DOCKER_REGISTRY}/${IMAGE_TAG}"

        // Inject a credential from the Jenkins credential store as an env var
        // The value is masked in all console output — shown as ****
        DOCKER_CREDS     = credentials('docker-registry-credentials')
        // credentials() for usernamePassword creates two variables:
        // DOCKER_CREDS_USR (username) and DOCKER_CREDS_PSW (password)
    }

    stages {

        stage('Checkout') {
            steps {
                checkout scm
                script {
                    // Capture the short git commit hash dynamically
                    // returnStdout: true — captures output as a string
                    // trim() — removes the trailing newline the shell adds
                    env.GIT_SHORT = sh(
                        script: 'git rev-parse --short HEAD',
                        returnStdout: true
                    ).trim()

                    // Now override IMAGE_TAG to include the commit hash
                    env.IMAGE_TAG  = "${APP_NAME}:${BUILD_NUMBER}-${env.GIT_SHORT}"
                    env.FULL_IMAGE = "${DOCKER_REGISTRY}/${env.IMAGE_TAG}"

                    echo "Building image: ${env.FULL_IMAGE}"
                }
            }
        }

        stage('Test') {
            // Stage-level environment variable — only available in this stage
            environment {
                TEST_REPORT_DIR = "${WORKSPACE}/build/test-results"
            }
            steps {
                sh './gradlew test'
                sh "echo Test reports in: ${TEST_REPORT_DIR}"
            }
        }

        stage('Docker Build and Push') {
            steps {
                sh """
                    # Shell variables — ${FULL_IMAGE} is expanded by the shell
                    docker login -u ${DOCKER_CREDS_USR} -p ${DOCKER_CREDS_PSW} ${DOCKER_REGISTRY}
                    docker build -t ${FULL_IMAGE} .
                    docker push ${FULL_IMAGE}
                """
            }
        }

        stage('Deploy to Staging') {
            steps {
                sh """
                    kubectl set image deployment/${APP_NAME} \
                      ${APP_NAME}=${FULL_IMAGE} \
                      --namespace=${DEPLOY_ENV}
                """
                echo "Deployed ${FULL_IMAGE} to ${DEPLOY_ENV}"
            }
        }

        stage('Smoke Test') {
            steps {
                // STAGING_URL defined at pipeline level — available here
                sh "curl --fail --retry 3 ${STAGING_URL}/health"
                echo "Smoke test passed for ${APP_NAME} on ${DEPLOY_ENV}"
            }
        }

    }

    post {
        success {
            echo "✅ ${APP_NAME} build ${BUILD_NUMBER} deployed successfully to ${DEPLOY_ENV}"
        }
        failure {
            echo "❌ ${APP_NAME} build ${BUILD_NUMBER} failed — check ${BUILD_URL}"
        }
        always { cleanWs() }
    }
}