Parameters block declaration in Jenkins - Mini Project: Build & Apply

Jenkins Pipeline: Parameters Block Declaration

📖 Scenario: You are setting up a Jenkins pipeline for a simple project. You want to allow users to provide input parameters when they start the pipeline. This helps customize the build process based on user choices.

🎯 Goal: Build a Jenkins pipeline script that declares a parameters block with specific input parameters. This will let users enter values before the pipeline runs.

📋 What You'll Learn

Declare a parameters block in the Jenkins pipeline script

Add a string parameter named BRANCH_NAME with default value main

Add a boolean parameter named RUN_TESTS with default value true

Add a choice parameter named DEPLOY_ENV with choices dev, qa, prod

Print the values of all parameters in the pipeline

💡 Why This Matters

🌍 Real World

Jenkins pipelines often need user input to decide which branch to build, whether to run tests, or where to deploy. Parameters block lets users provide this input easily.

💼 Career

Knowing how to declare and use parameters in Jenkins pipelines is essential for DevOps engineers to create flexible and user-friendly CI/CD workflows.

1

Create the basic Jenkins pipeline script

Create a Jenkins pipeline script with a pipeline block and an empty parameters block inside pipeline. Use agent any to run on any available agent.

Jenkins

pipeline {
    agent any
    parameters {
        // Your code here
    }
    stages {
        stage('Example') {
            steps {
                echo 'Pipeline started'
            }
        }
    }
}

Need a hint?

The parameters block goes inside the pipeline block but before stages.

2

Add string and boolean parameters

Inside the parameters block, add a string parameter named BRANCH_NAME with default value main, and a boolean parameter named RUN_TESTS with default value true.

Jenkins

pipeline {
    agent any
    parameters {
        // Add string parameter BRANCH_NAME with default 'main'
        // Add boolean parameter RUN_TESTS with default true
    }
    stages {
        stage('Example') {
            steps {
                echo 'Pipeline started'
            }
        }
    }
}

Need a hint?

Use string(name: '', defaultValue: '', description: '') and booleanParam(name: '', defaultValue: , description: '') inside parameters.

3

Add a choice parameter for deployment environment

Add a choice parameter named DEPLOY_ENV inside the parameters block. It should have choices dev, qa, and prod.

Jenkins

pipeline {
    agent any
    parameters {
        string(name: 'BRANCH_NAME', defaultValue: 'main', description: 'Branch to build')
        booleanParam(name: 'RUN_TESTS', defaultValue: true, description: 'Run tests?')
        // Add choice parameter DEPLOY_ENV with choices 'dev', 'qa', 'prod'
    }
    stages {
        stage('Example') {
            steps {
                echo 'Pipeline started'
            }
        }
    }
}

Need a hint?

Use choice(name: '', choices: ['option1', 'option2'], description: '') inside parameters.

4

Print all parameter values in the pipeline

Inside the steps block of the Example stage, add echo statements to print the values of BRANCH_NAME, RUN_TESTS, and DEPLOY_ENV parameters.

Jenkins

pipeline {
    agent any
    parameters {
        string(name: 'BRANCH_NAME', defaultValue: 'main', description: 'Branch to build')
        booleanParam(name: 'RUN_TESTS', defaultValue: true, description: 'Run tests?')
        choice(name: 'DEPLOY_ENV', choices: ['dev', 'qa', 'prod'], description: 'Deployment environment')
    }
    stages {
        stage('Example') {
            steps {
                // Print BRANCH_NAME
                // Print RUN_TESTS
                // Print DEPLOY_ENV
            }
        }
    }
}

Need a hint?

Use echo "BRANCH_NAME: ${params.BRANCH_NAME}" to print parameter values inside steps.