Build steps execution in Jenkins - Mini Project: Build & Apply

Build steps execution

📖 Scenario: You are setting up a Jenkins pipeline to automate a simple build process for a software project. The build process has multiple steps that need to run in order.

🎯 Goal: Build a Jenkins pipeline script that defines three build steps: checkout, build, and test. Each step should print a message indicating it is running.

📋 What You'll Learn

Create a Jenkins pipeline script using the pipeline and stages syntax

Define three stages named Checkout, Build, and Test

Each stage should have a steps block that prints a message using echo

The messages must be exactly: 'Checking out code...', 'Building the project...', and 'Running tests...'

💡 Why This Matters

🌍 Real World

Jenkins pipelines automate software builds, tests, and deployments in many companies to save time and reduce errors.

💼 Career

Understanding build steps execution is essential for DevOps engineers and automation specialists working with CI/CD tools like Jenkins.

1

Create the Jenkins pipeline skeleton

Write the initial Jenkins pipeline script with a pipeline block and an empty stages block.

Jenkins

pipeline {
    agent any
    stages {
        // Your code here
    }
}

Hint

Start by writing pipeline { then specify agent any and add an empty stages { } block inside.

2

Add the Checkout stage

Inside the stages block, add a stage named Checkout with a steps block that uses echo to print 'Checking out code...'.

Jenkins

pipeline {
    agent any
    stages {
        // Add Checkout stage here
    }
}

Hint

Use stage('Checkout') and inside it add steps { echo 'Checking out code...' }.

3

Add the Build and Test stages

Add two more stages inside stages: Build and Test. Each should have a steps block that prints 'Building the project...' and 'Running tests...' respectively using echo.

Jenkins

pipeline {
    agent any
    stages {
        stage('Checkout') {
            steps {
                echo 'Checking out code...'
            }
        }
        // Add Build and Test stages here
    }
}

Hint

Add stage('Build') and stage('Test') with steps { echo ... } inside each.

4

Run the pipeline and display output

Print the entire Jenkins pipeline script so it can be run and shows the three messages in order.

Jenkins

pipeline {
    agent any
    stages {
        stage('Checkout') {
            steps {
                echo 'Checking out code...'
            }
        }
        stage('Build') {
            steps {
                echo 'Building the project...'
            }
        }
        stage('Test') {
            steps {
                echo 'Running tests...'
            }
        }
    }
}
// Your code here to run or print the pipeline script

Hint

When you run this Jenkins pipeline, it will print the three messages in order during the build.

Practice

1. What is the main purpose of build steps in a Jenkins pipeline?

easy

A. To manage Jenkins plugins and updates

B. To create user accounts on the Jenkins server

C. To monitor server hardware performance

D. To run commands that compile, test, and package software automatically

Solution

1. Step 1: Understand what build steps do

   Build steps are commands executed during a Jenkins pipeline to automate tasks.

2. Step 2: Identify the correct purpose

   They help compile, test, and package software automatically as part of the build process.

3. Final Answer:

   To run commands that compile, test, and package software automatically -> Option D

4. Quick Check:

   Build steps = automate build tasks [OK]

Hint: Build steps automate software tasks in order [OK]

Common Mistakes:

• Confusing build steps with server management
• Thinking build steps create users
• Assuming build steps monitor hardware

2. Which of the following is the correct syntax to add a shell build step in a Jenkins pipeline script?

easy

A. sh 'echo Hello World'

B. shell: echo Hello World

C. execute shell { echo Hello World }

D. run shell echo Hello World

Solution

1. Step 1: Recall Jenkins pipeline shell step syntax

   In Jenkins scripted or declarative pipelines, shell commands run with the sh step and a string argument.

2. Step 2: Match the correct syntax

   The correct syntax is sh 'command', so sh 'echo Hello World' is valid.

3. Final Answer:

   sh 'echo Hello World' -> Option A

4. Quick Check:

   Shell step uses sh 'command' [OK]

Hint: Use sh 'command' for shell steps in Jenkins [OK]

Common Mistakes:

• Using incorrect keywords like shell: or execute shell
• Omitting quotes around the command
• Writing commands without the sh step

3. Given this Jenkins pipeline snippet, what will be the output in the console?

stage('Build') {
  steps {
    sh 'echo Start Build'
    sh 'echo Build Complete'
  }
}

medium

A. Start Build only

B. Build Complete\nStart Build

C. Start Build\nBuild Complete

D. No output, commands are skipped

Solution

1. Step 1: Understand step execution order

   Jenkins runs build steps in the order they appear inside the stage.

2. Step 2: Trace the commands

   First, echo Start Build runs, printing "Start Build". Then echo Build Complete runs, printing "Build Complete".

3. Final Answer:

   Start Build\nBuild Complete -> Option C

4. Quick Check:

   Steps run in order, output matches [OK]

Hint: Steps run top to bottom inside stages [OK]

Common Mistakes:

• Assuming steps run in reverse order
• Thinking only first step outputs
• Believing steps might be skipped without error

4. You have this Jenkins pipeline snippet:

stage('Test') {
  steps {
    sh 'echo Running tests'
    sh 'exit 1'
    sh 'echo Tests done'
  }
}

What will happen when this pipeline runs?

medium

A. All commands run, including 'echo Tests done'

B. Pipeline stops at 'exit 1' and 'echo Tests done' is not executed

C. Pipeline ignores 'exit 1' and continues

D. Pipeline skips 'echo Running tests' and runs others

Solution

1. Step 1: Understand shell step failure behavior

   In Jenkins, if a shell command returns a non-zero exit code (like exit 1), the pipeline fails and stops executing further steps.

2. Step 2: Analyze the commands

   After sh 'exit 1' fails, the next step sh 'echo Tests done' will not run.

3. Final Answer:

   Pipeline stops at 'exit 1' and 'echo Tests done' is not executed -> Option B

4. Quick Check:

   Non-zero exit stops pipeline [OK]

Hint: Non-zero exit code stops pipeline steps [OK]

Common Mistakes:

• Assuming pipeline continues after failure
• Thinking all steps always run
• Ignoring exit codes in shell steps

5. You want to run two build steps in a Jenkins pipeline: first compile code, then run tests only if compile succeeds. Which pipeline snippet correctly implements this?

hard

A. stage('Build') {
steps {
sh 'compile.sh'
script {
if (currentBuild.result != 'FAILURE') {
sh 'test.sh'
}
}
}
}

B. stage('Build') {
steps {
sh 'compile.sh || true'
sh 'test.sh'
}
}

C. stage('Build') {
steps {
sh 'compile.sh'
}
}
stage('Test') {
steps {
sh 'test.sh'
}
}

D. }
}
'hs.tset' hs
'eurt || hs.elipmoc' hs
{ spets
{ )'dliuB'(egats

Solution

1. Step 1: Understand conditional execution in Jenkins pipeline

   To run tests only if compile succeeds, you need to check the build status before running tests.

2. Step 2: Analyze options

   stage('Build') { steps { sh 'compile.sh' script { if (currentBuild.result != 'FAILURE') { sh 'test.sh' } } } } uses a script block to check if the build is not failed before running tests, ensuring tests run only after successful compile.

3. Final Answer:

   sh 'compile.sh'; script { if (currentBuild.result != 'FAILURE') { sh 'test.sh' } } -> Option A

4. Quick Check:

   Conditional test run uses script and build status check [OK]

Hint: Use script block to conditionally run steps [OK]

Common Mistakes:

• Running all steps unconditionally
• Using shell || true which ignores compile failure
• Splitting stages without controlling flow