# Conditional stage in Jenkins pipeline

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Published 2022-12-03

This tutorial explains how we can execute a stage in Jenkins when a condition occurs. Also, inside a stage we can have a condition for doing or not a task.

First of all I want to highlight that a prerequisite for this article is Create Declarative Pipeline tutorial.

Now we modify the Jenkinsfile in GitHub. The new Jenkinsfile will be like this:

def var1 = 0

pipeline {
    agent any
    
    stages {
        stage('Stage 1') {
            when { 
                expression {var1 == 1}
            }
            steps {
                echo 'Stage 1 ...'
            }
        }
        stage('Stage 2') {
            when { 
                expression {var1 != 1}
            }
            steps {
                echo 'Stage 2 ...'
            }
        }
        
        stage('Stage 3') {
            steps {
                echo 'within myStage'
                script {
                    if (var1 == 1) {
                        echo 'Stage 3/A'
                    } else {
                        echo 'Stage 3/B'
                    }
                }
            }
        }
    }
}

When we run the pipeline, we will get:

Also, the Console Output has the following content:

Stage "Stage 1" skipped due to when conditional
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Stage 2)
[Pipeline] echo
Stage 2 ...
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Stage 3)
[Pipeline] echo
within myStage
[Pipeline] script
[Pipeline] {
[Pipeline] echo
Stage 3/B
[Pipeline] }
[Pipeline] // script
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // withEnv
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
Finished: SUCCESS

Conclusions

We can change the pipeline execution at the stage level and inside the stage as well
when is the key word which allow or not the execution of a stage
in a stage we can run a scripts which can have conditionals inside