I have two Jenkinsfile for sample: The content of A_Jenkinsfile is:

pipeline {
    agent any
    stages {
        stage("first") {
            steps {
                script {
                 foo = "bar"
                }
            sh "echo ${foo}"
            }
        }
        stage("two") {
            steps {
            sh "echo ${foo}"
            }
        }
    }
}

The other one is B_Jenkinsfile and its content is:

pipeline {
    agent any
    stages {
        stage("first") {
            steps {
                script {
                 def foo = "bar"
                }
            sh "echo ${foo}"
            }
        }
        stage("two") {
            steps {
            sh "echo ${foo}"
            }
        }
    }
}

When I build them, B_Jenkinsfile is failed and A_Jenkinsfile is success.

What is differences between either of using def and without using def in Jenkinsfile in script block?

CodePudding user response：

There are two types of Pipeline syntax. Declarative Pipeline and Scripted Pipeline. A declarative pipeline starts with a pipeline {} wrapper and will have Stages and Steps. Declarative pipeline limits what is available to the user with a more strict and pre-defined structure. Where in scripted Pipeline it's more closer to groovy, and users will have more flexibility on what they can do. When you run something in a Script block in a declarative Pipeline, The script step takes a block of the Scripted Pipeline and executes that in the Declarative Pipeline. Basically, it runs a Groovy script for you. So your question can be rephrased as what def means in a Groovy script.

Simply in a Groovy script, if you omit adding the def keyword the variable will be added to the current script's binding. So it will be considered as a Global variable. If you use def the variable will be scoped, and you will only be able to use it in the current script block. There are multiple detailed answers for this here, so I'm not going to repeat them.