Mulitbranch pipeline example with loading external groovy pipelines

cd.groovy

def deployProjectToEnvStage(String env_name) {
    catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') {
        stage("Deploy to ${env_name}") {
            echo 'Running Deploy stage in cd.groovy...'
            sh "echo 'Deploying project to ${env_name}'"

            script {
                if ("${env_name}" == 'dev1') {
                    sh 'sleep 1'
                }
                if ("${env_name}" == 'dev2') {
                    sh 'sleep 2'
                    error 'chaos'
                }
                if ("${env_name}" == 'dev3') {
                    sh 'sleep 3'
                }
            }
        }
    }
}

// A function to run all stages together
def runPipeline() {
    deployProjectToEnvStage('dev1')
    deployProjectToEnvStage('dev2')
    deployProjectToEnvStage('dev3')
}

return this

ci.groovy

def buildStage() {
    stage('Build') {
        container('maven') {
            echo 'Running Maven Build stage in ci.groovy...'
            sh 'echo "Building project..."'
            sh 'mvn clean install'
        }
    }
}

def testStage() {
    stage('Unit Tests') {
        echo 'Running Unit Test stage in ci.groovy...'
        sh 'echo "Running tests..."'
    }
}

def dockerStage() {
    stage('Docker build') {
        container('dind') {   //todo: add to podTemplate (replace with kaniko later)
            echo 'Running Docker build stage in ci.groovy...'
            sh 'echo "Running docker..."'
        }
    }
}

// A function to run all stages together
def runPipeline() {
    buildStage()
    testStage()
    dockerStage()
}

return this

Jenkinsfile

pipeline {
    agent {
        kubernetes {
            idleMinutes 2
            yaml '''
                    metadata:
                      labels:
                        some-label: some-label-value
                    spec:
                      containers:
                      - name: jnlp
                        env:
                        - name: CONTAINER_ENV_VAR
                          value: jnlp
                      - name: maven
                        image: maven:3.9.9-eclipse-temurin-21-alpine
                        command:
                         - cat
                        tty: true
            '''
        }
    }
    options {
        buildDiscarder(logRotator(numToKeepStr: '10'))
        timeout(time: 1, unit: 'HOURS')
        skipDefaultCheckout()
        timestamps()
    }
    stages {
        stage('SCM') {
            steps {
                checkout scm   // multibranch pipelines
            }
        }

        stage('Setup') {
            steps {
                script {
                    def ci
                    def cd

                    // CHECKOUT JENKINS GROOVY FILES:
                    dir('.jenkins') {
                        checkout([
                            $class: 'GitSCM',
                            branches: [[name: 'main']],
                            userRemoteConfigs: [[
                                url: '........................................',
                                credentialsId: '...............................'
                            ]]
                        ])

                        ci = load 'ci.groovy'
                        cd = load 'cd.groovy'
                    }

                    ci.runPipeline()
                    cd.runPipeline()
                }
            }
        }
    }
}