Understanding Jenkins Declarative Pipeline Syntax

Jenkins pipelines enable users to build complete continuous delivery (CD) pipelines as part of their application code, storing build, test, and delivery steps in a Jenkinsfile . The declarative pipeline syntax offers a simple predefined hierarchy that is accessible to users of all experience levels.

Below is a minimal pipeline that runs on an agent and contains a single Build stage executing a Maven install command:

pipeline {
  agent {
      label ''
  }
  stages {
    stage('Build') {
      steps{
      sh 'mvn install'
    }
   }
  }
}

An extended example demonstrates using a Docker container to build a Java application with Maven, limiting execution to the master branch and applying a six‑hour timeout:

pipeline {
  agent {
    docker {
      label ‘docker-node’
      image ‘maven’
      args ‘-v /tmp:/tmp -p 80:80’
    }
  }
  environment {
    GIT_COMMITTER_NAME = ‘jenkins’
  }
  options {
    timeout(6, HOURS)
  }
  stages {
    stage(‘Build’) {
      steps {
         sh ‘mvn clean install’
      }
    }

    stage(‘Archive’) {
      when {
        branch ‘*/master’
      }
      steps {
        archive ‘*/target/**/*’
        junit ‘*/target/surefire-reports/*.xml’
      }
    }
  }

  post {
    always {
       deleteDir()
    }
  }
}

Declarative Pipeline Syntax (Required)

pipeline : defines a Jenkins pipeline.

agent : specifies the node that executes pipeline stages. Options include label for a Jenkins node label or docker to run inside a Docker container (with image and args ).

stages : the collection of stages in the pipeline.

stage : a single stage within the pipeline.

steps : individual build steps such as sh , bat , timeout , echo , archive , junit , etc.

when : conditions for running a stage (e.g., based on branch or variable).

Additional sections can appear inside a stage: agent , environment , tools , and post .

Declarative Pipeline Syntax (Optional)

environment : defines environment variables for the pipeline.

options : sets pipeline execution options such as skipDefaultCheckout , timeout , buildDiscarder , and disableConcurrentBuilds .

tools : makes pre‑installed tools available in the pipeline.

triggers : configures pipeline scheduling and build triggers.

parameters : defines runtime parameters for the pipeline.

post : defines actions to run after the pipeline completes, with conditions like always , success , and failure .

About Us

Ze Yang is a DevOps practitioner focusing on enterprise‑level DevOps operations and development. He shares practical experience through courses on Linux operations and DevOps technologies, offering content derived from real‑world enterprise applications.