How to use String build parameters in Jenkinsfile

In this tutorial, we will learn how to add string parameters in Jenkinsfile, which allows users to input custom text values when triggering the pipeline. This makes the pipeline more flexible and reusable.

We can achieve this using the parameters block and the string parameter type in Jenkinsfile.

Jenkinsfile

Here is the sample Jenkinsfile 13-Jenkinsfile-maven-build-parameters-string

pipeline {
  agent any
  options {
    disableConcurrentBuilds()
    disableResume()
    buildDiscarder(logRotator(numToKeepStr: '10'))
    timeout(time: 1, unit: 'HOURS')
  }
  tools {
    maven 'maven-3.6.3' 
  }
  parameters {
    string(name: 'MAVEN_GOAL', defaultValue: 'compile', description: 'Maven goal eg: compile, test, package or install')
  }
  stages {
    stage ('Build') {
      steps {
        sh "mvn clean ${params.MAVEN_GOAL}"
      }
    }
  }
  post {
    always {
      deleteDir()
    }
  }
}

Explanation

In the standard Jenkins pipeline syntax, the parameters block is used to define input parameters that the user can provide when running the build.

Inside the parameters block, we are defining a parameter named MAVEN_GOAL using the string directive.

• name: The name of the parameter variable (e.g., 'MAVEN_GOAL'). This variable can be accessed in the pipeline steps.
• defaultValue: The default value that will be pre-filled if the user doesn't change it (e.g., 'compile').
• description: A helpful description shown to the user in the Jenkins UI when building with parameters.

In the Build stage, we access the value of the parameter using ${params.MAVEN_GOAL}.

sh "mvn clean ${params.MAVEN_GOAL}"

When you run this pipeline for the first time, Jenkins will register the parameters. On subsequent runs, you will see a "Build with Parameters" option in the Jenkins UI instead of "Build Now".

Clicking "Build with Parameters" will show a form where you can enter the value for MAVEN_GOAL.

If you enter package, the command executed will be mvn clean package. If you leave it as default, it will run mvn clean compile.

Reference

• GitHub Repository

🧠 Quick Quiz — String Parameters

#

Which syntax is used to access the value of a parameter named MY_PARAM inside a pipeline script?

${params.MY_PARAM}

${env.MY_PARAM}

$MY_PARAM

${MY_PARAM}

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