Why scripted pipelines offer flexibility in Jenkins - See It in Action

Why scripted pipelines offer flexibility

📖 Scenario: You are a DevOps engineer working with Jenkins to automate software builds and deployments. You want to understand why scripted pipelines in Jenkins provide more flexibility compared to declarative pipelines.

🎯 Goal: Build a simple Jenkins scripted pipeline that demonstrates flexibility by using variables, conditional logic, and loops.

📋 What You'll Learn

Create a variable to hold a list of build stages

Add a configuration variable to control whether to run tests

Use a loop to iterate over the stages and run them

Print the stages that were run

💡 Why This Matters

🌍 Real World

In real projects, scripted pipelines help automate complex workflows that need decisions and loops, like running tests only on certain branches or deploying to different environments.

💼 Career

Understanding scripted pipelines is important for DevOps roles because it allows customizing Jenkins automation beyond simple linear steps, making your automation smarter and more adaptable.

1

Create a list of build stages

Create a variable called stages and assign it the list ["Build", "Test", "Deploy"].

Jenkins

# Create a variable called stages with the list ["Build", "Test", "Deploy"]
stages = []
# Your code here

Need a hint?

Use square brackets to create a list and assign it to stages.

2

Add a configuration variable to control testing

Create a variable called runTests and set it to true to control whether the Test stage runs.

Jenkins

stages = ["Build", "Test", "Deploy"]
# Create a variable called runTests and set it to true
runTests = false
# Your code here

Need a hint?

Use true (lowercase) to set the boolean variable runTests.

3

Use a loop and conditional to run stages

Use a for loop with variable stage to iterate over stages. Inside the loop, use an if statement to skip the Test stage if runTests is false. Print "Running stage" for each stage run.

Jenkins

stages = ["Build", "Test", "Deploy"]
runTests = true
# Use a for loop to iterate over stages
# Use if to skip Test stage if runTests is false
# Print "Running  stage" for each stage run

Need a hint?

Use continue to skip the Test stage when runTests is false.

4

Print the stages that were run

Add a print statement after the loop to display "Stages completed: " followed by the list of stages that were run. Use a list called completedStages to collect stages inside the loop.

Jenkins

stages = ["Build", "Test", "Deploy"]
runTests = true
completedStages = []
for (stage in stages) {
    if (stage == "Test" && !runTests) {
        continue
    }
    println("Running ${stage} stage")
    // Add stage to completedStages list
}

// Print the completed stages

Need a hint?

Use add() to add stages to the list and print it after the loop.