Demo Declarative vs Scripted Pipeline

In this guide, we’ll compare Declarative and Scripted Jenkins pipelines using two separate Jenkinsfiles in the same Git repository. By the end, you’ll understand the key differences in configuration, SCM handling, and runtime behavior.

Repository Structure

Our repo declarative-vs-scripted-pipeline has two branches (demo-1 and demo-2) and two Jenkinsfiles:

• Jenkinsfile.declarative
• Jenkinsfile.scripted

Jenkinsfile.declarative

The Declarative Pipeline syntax includes an implicit checkout and a post section for cleanup:

pipeline {
  agent any

  stages {
    stage('Echo Message') {
      steps {
        sh 'ls -ltr'
        sh 'echo "This is executed within a DECLARATIVE Pipeline"'
      }
    }
  }

  post {
    always {
      sh 'echo "This will always run"'
      sh 'rm -rf *'
    }
  }
}

Jenkinsfile.scripted

Scripted Pipelines rely on explicit SCM operations and Groovy control flow:

node {
  try {
    stage('Echo Message') {
      sh 'ls -ltr'
      sh 'echo "This is executed within a SCRIPTED Pipeline"'
    }
  } catch (err) {
    echo "Failed: ${err}"
  } finally {
    sh 'echo "This will always run."'
    // sh 'rm -rf *'
  }
}

1. Create the Pipeline Job

1. In Jenkins, click New Item.
2. Enter d-v-s-pipeline, select Pipeline, and click OK.

2. Configure the Declarative Pipeline

1. Under Pipeline → Definition, choose Pipeline script from SCM.
2. Enter your Git Repository URL, credentials (if any), and branch demo-1.
3. In Script Path, set Jenkinsfile.declarative.
4. Save and click Build.

3. Running the Declarative Pipeline

After the build starts, you’ll see these stages:

1. Declarative: Checkout SCM (automatic)
2. Echo Message
3. Declarative: Post Actions

Sample log excerpt:

[Pipeline] checkout scm
 > git config core.sparsecheckout # timeout=10
[Pipeline] sh
+ echo This is executed within a DECLARATIVE Pipeline
This is executed within a DECLARATIVE Pipeline
[Pipeline] sh
+ echo This will always run
This will always run

Declarative pipelines handle SCM checkout and cleanup automatically.

4. Switch to the Scripted Pipeline

1. Return to Configure.
2. Change Script Path to Jenkinsfile.scripted.
3. Save and Build.

Log excerpt:

[Pipeline] stage (Echo Message)
[Pipeline] sh
+ ls -ltr
total 0
[Pipeline] sh
+ echo This is executed within a SCRIPTED Pipeline
This is executed within a SCRIPTED Pipeline
[Pipeline] sh
+ echo This will always run.
This will always run.

Notice: No checkout stage—only your custom steps run.

5. Add Checkout to Scripted Pipeline

Edit Jenkinsfile.scripted to include checkout scm inside the stage:

node {
  try {
    stage('Echo Message') {
      checkout scm
      sh 'ls -ltr'
      sh 'echo "This is executed within a SCRIPTED Pipeline"'
    }
  } catch (err) {
    echo "Failed: ${err}"
  } finally {
    sh 'echo "This will always run"'
    // sh 'rm -rf *'
  }
}

Commit and build. You’ll now see both checkout and shell steps:

Log excerpt:

[Pipeline] checkout scm
 > git fetch --tags --force --progress http://... # timeout=10
[Pipeline] sh
+ ls -ltr
total 8
-rw-r--r-- 1 jenkins jenkins 311 Nov 10 12:29 Jenkinsfile.scripted
...

Summary of Differences

For seamless SCM integration, stage restarts, and easier maintenance, Declarative Pipelines are generally recommended.

Links and References

• Jenkins Pipeline Syntax
• Declarative Pipeline Directive Reference
• Scripted Pipeline