jenkins

Intro

Pipeline Syntax

Scripted	Declarative
First syntax	recent addition
groovy engine	easier to get started, but not that powerful
advanced scripting, high flexibility	pre-defined structure
node {}	pipeline {agent any stages {...}}

pipeline {
    // where to execute 
    agent any
    // the pipeline section we all know and love: stages! :D
    stages {
        // CI: Focuses on integrating code changes and ensuring the build and test processes are automated.
        stage('install') {
            steps {
                echo 'Installing requirements...'
            }
        }
        stage('Build') {
            steps {
                echo 'Building..'
            }
        }
        stage('Test') {
            steps {
                echo 'Testing..'
            }
        }
        stage('Report') {
            steps {
                echo 'Reporting....'
            }
        }
        // CD: Ensure that the code is always in a deployable state and reduce the time to release features to users.
        stage('Deploy') {
            steps {
                echo 'Deploying....'
            }
        }
    }
    post {
        always {
            echo 'Done'
        }
        success {
            // example: send msg to microsoft teams
        }
        failure {
            // example: send msg to microsoft teams
        }
    }
}

Define conditions

pipeline {
    agent any
    stages {
        stage('install') {
            when {
                expression {
                    env.BRANCH_NAME == 'dev' || env.BRANCH_NAME == 'master'
                }
            }
            steps {
                echo 'Installing requirements...'
            }
        }
        stage('Build') {
            steps {
                echo 'Building..'
            }
        }
    }    
}

Enviromental Variables

find all pre-defined vars in jenkinsurl + /env-vars.html

pipeline {
    agent any
    stages {
        stage('install') {
            when {
                expression {
                    BRANCH_NAME == 'dev' ||  BRANCH_NAME == 'master'
                }
            }
            steps {
                echo 'Installing requirements...'
            }
        }
        stage('Build') {
            steps {
                echo 'Building..'
            }
        }
       
}

pipeline {
    agent any
    environment {
        TEST_SERVER = 'www.url.com'
        BOOLEAN_VAR  = 'true' //boolean value as string
    }
    stages {
        stage('install') {
            when {
            expression {
                !env.BOOLEAN_VAR.toBoolean()
                }
            }
            steps {
                echo 'Installing requirements...'
            }
        }
        stage('Build') {
            steps {
                echo 'Building..'
            }
        }
    }   
}

Credentials in Jenkinsfile

Variant 1 : using `withCredentials` in each seperate stage

pipeline {
    agent any
    stages {
        stage('install') {
            steps {
                echo 'Installing requirements...'
            }
        }
        stage('deploy') {
            steps {
                echo 'deploying the app ...'
                // usernamePassword is the type of credential that I created in jenkins server
                withCredentials([usernamePassword(credentialsId: test-server, usernameVariable: 'USER', passwordVariable: 'PASSWORD')]) {
                    def url = 'www.url.com'
                    echo "${USER}"
                    // sh "docker login  url -u USER  -p PASSWORD
                }
            }
        }
       
    }
}

variant 2: using environment

pipeline {
    agent any
    environment {
        TEST_SERVER  = credentials('test-server')
        TEST_SERVER_URL = 'www.url.com'
    }
    stages {
        stage('install') {
            steps {
                echo 'Installing requirements...'
            }
        }
        stage('deploy') {
            steps {
                echo 'deploying the app ...'
                echo "${TEST_SERVER_USR}"
                // Jenkins always adds _USR and _PSW endings to the names of the variables.
                //sh "docker login '${TEST_SERVER_URL}' --password '${TEST_SERVER_PSW}' --username '${TEST_SERVER_USR}'"
            }
        }
       
    }
}

Build Tools

pipeline {
    agent any
    tools {
        nodejs "node-22.2"
    }
    stages {
        stage('install') {
            steps {
                sh 'npm -v'
            }
        }
    }
}

Others

Link to how install Jenkins server on aws https://d1.awsstatic.com/Projects/P5505030/aws-project_Jenkins-build-server.pdf