Post-build actions in Jenkins - Mini Project: Build & Apply

Jenkins Post-build Actions Setup

📖 Scenario: You are setting up a Jenkins job to automate a simple build process. After the build completes, you want Jenkins to perform some actions automatically, like archiving build artifacts and sending notifications.

🎯 Goal: Learn how to configure post-build actions in a Jenkins job using the Jenkinsfile syntax.

📋 What You'll Learn

Create a Jenkinsfile with a basic pipeline

Add a post-build action to archive artifacts

Add a post-build action to send a notification

Print confirmation that post-build actions are configured

💡 Why This Matters

🌍 Real World

In real projects, Jenkins post-build actions automate tasks like saving build outputs and notifying teams, saving time and reducing errors.

💼 Career

Understanding Jenkins post-build actions is essential for DevOps engineers to automate continuous integration and delivery pipelines effectively.

1

Create a basic Jenkins pipeline

Create a Jenkinsfile with a pipeline block that has an empty agent any and an empty stages block.

Jenkins

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

Hint

Start with the basic Jenkins pipeline structure: pipeline { agent any stages { } }.

2

Add a post-build action to archive artifacts

Add a post block inside the pipeline with a always condition that uses archiveArtifacts to archive files matching "**/*.jar".

Jenkins

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

Hint

Use post { always { archiveArtifacts artifacts: '**/*.jar' } } to archive all JAR files after every build.

3

Add a post-build action to send a notification

Inside the same always block in the post section, add a echo step that prints "Build completed - notifications sent".

Jenkins

pipeline {
    agent any
    stages {
    }
    post {
        always {
            archiveArtifacts artifacts: '**/*.jar'
            // Your code here
        }
    }
}

Hint

Add echo 'Build completed - notifications sent' inside the always block to simulate sending a notification.

4

Print confirmation of post-build actions

Add a print statement in the Jenkinsfile script that outputs exactly "Post-build actions configured successfully".

Jenkins

pipeline {
    agent any
    stages {
    }
    post {
        always {
            archiveArtifacts artifacts: '**/*.jar'
            echo 'Build completed - notifications sent'
        }
    }
}

// Your code here

Hint

Use print('Post-build actions configured successfully') outside the pipeline block to confirm setup.

Practice

1. What is the main purpose of Post-build actions in Jenkins?

easy

A. To start the build process

B. To write the build script

C. To perform tasks automatically after the build finishes

D. To configure the Jenkins server settings

Solution

1. Step 1: Understand Jenkins build phases

   Jenkins runs build steps first, then post-build actions after the build ends.

2. Step 2: Identify the role of post-build actions

   Post-build actions automate tasks like notifications, archiving, or cleanup after the build completes.

3. Final Answer:

   To perform tasks automatically after the build finishes -> Option C

4. Quick Check:

   Post-build actions = tasks after build [OK]

Hint: Post-build actions run after build ends to automate tasks [OK]

Common Mistakes:

• Confusing post-build actions with build steps
• Thinking post-build actions start the build
• Assuming post-build actions configure Jenkins server

2. Which of the following is the correct syntax to add a post-build action in a Jenkins pipeline script?

easy

A. build {
post {
echo 'Build finished'
}
}

B. pipeline {
postbuild {
echo 'Build finished'
}
}

C. steps {
post {
echo 'Build finished'
}
}

D. post {
always {
echo 'Build finished'
}
}

Solution

1. Step 1: Recall Jenkins pipeline post syntax

   In declarative pipelines, post block defines post-build actions with conditions like always.

2. Step 2: Match syntax options

   post { always { echo 'Build finished' } } uses correct post { always { ... } } syntax. Others use invalid blocks like build or postbuild.

3. Final Answer:

   post { always { echo 'Build finished' } } -> Option D

4. Quick Check:

   Post block syntax = post { always { echo 'Build finished' } } [OK]

Hint: Use 'post { always { ... } }' for post-build actions in pipeline [OK]

Common Mistakes:

• Using 'postbuild' instead of 'post'
• Placing post block inside 'steps'
• Using 'build' block incorrectly

3. Given this Jenkins pipeline snippet, what will be printed after the build finishes successfully?

pipeline {
  agent any
  stages {
    stage('Build') {
      steps {
        echo 'Building...'
      }
    }
  }
  post {
    success {
      echo 'Build succeeded!'
    }
    failure {
      echo 'Build failed!'
    }
  }
}

medium

A. Building...
Build failed!

B. Building...
Build succeeded!

C. Build succeeded!

D. Build failed!

Solution

1. Step 1: Analyze build steps

   The pipeline prints 'Building...' during the build stage.

2. Step 2: Check post-build actions on success

   On successful build, the success block runs, printing 'Build succeeded!'.

3. Final Answer:

   Building... Build succeeded! -> Option B

4. Quick Check:

   Success post block runs after build [OK]

Hint: Success block runs only if build succeeds [OK]

Common Mistakes:

• Confusing failure block with success block
• Ignoring initial build echo
• Assuming post block runs before build

4. You wrote this Jenkins pipeline post section but the notification never sends on build failure:

post {
  failure {
    mail(to: '[e-mail]', subject: 'Build Failed')
  }
}

What is the likely problem?

medium

A. The mail step requires proper Jenkins email configuration

B. The failure block should be inside steps

C. The mail step requires a steps block inside failure

D. The post block must be inside steps

Solution

1. Step 1: Understand the mail step requirements

   The mail step requires the 'Email Extension Plugin' to be installed and SMTP server configured in Manage Jenkins > Configure System > Extended E-mail Notification.

2. Step 2: Identify the likely problem

   Without proper email configuration (SMTP host, port, credentials, etc.), the notification won't send even if the syntax is correct.

3. Final Answer:

   The mail step requires proper Jenkins email configuration -> Option A

4. Quick Check:

   Mail needs SMTP config [OK]

Hint: Configure SMTP in Jenkins for mail step [OK]

Common Mistakes:

• Not installing Email Extension plugin
• Not setting SMTP server details
• Missing 'from' address or credentials

5. You want to archive build artifacts only if the build succeeds and always send a notification email regardless of build result. Which Jenkins pipeline post section correctly implements this?

hard

A. post {
success {
archiveArtifacts 'build/*.jar'
}
always {
mail(to: '[e-mail]', subject: 'Build Notification')
}
}

B. post {
always {
archiveArtifacts 'build/*.jar'
mail(to: '[e-mail]', subject: 'Build Notification')
}
}

C. post {
success {
archiveArtifacts 'build/*.jar'
mail(to: '[e-mail]', subject: 'Build Notification')
}
}

D. post {
failure {
archiveArtifacts 'build/*.jar'
}
always {
mail(to: '[e-mail]', subject: 'Build Notification')
}
}

Solution

1. Step 1: Identify conditions for each action

   Archiving should happen only on success, so it goes inside success. Email should always send, so it goes inside always.

2. Step 2: Match options with conditions

   post { success { archiveArtifacts 'build/*.jar' } always { mail(to: '[e-mail]', subject: 'Build Notification') } } correctly separates archive in success and mail in always. Others mix conditions incorrectly.

3. Final Answer:

   post { success { archiveArtifacts 'build/*.jar' } always { mail(to: '[e-mail]', subject: 'Build Notification') } } -> Option A

4. Quick Check:

   Use success for archive, always for mail [OK]

Hint: Use 'success' for archive, 'always' for notifications [OK]

Common Mistakes:

• Putting archive in always block
• Sending mail only on success
• Archiving on failure instead of success