Error Jenkins Cannot define variable in pipeline stage

Question

I’m using the Jenkins pipeline feature to run a declarative pipeline in which I’m trying to define a variable:

pipeline {
   agent none
   stages {
       stage("first") {
           def foo = "foo" 
           sh "echo ${foo}"
       }
   }
}

I get the following error:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
WorkflowScript: 5: 
           def foo = "foo"
           ^

Answer 1

Try this, you have to define an environment variable in order to do this.

pipeline {
   environment {
     FOO = "foo"
   }
   agent none
   stages {
       stage("first") {
           sh "echo ${FOO}"
      }
   }
}

Answer 2

You can create variables before the pipeline block starts.

For Example,

def foo = "foo" 
pipeline {
   agent none
   stages {
       stage("first") {
           sh "echo ${foo}"
       }
   }
}

Comments

Hey, I have a small doubt. If variables are defined outside the pipeline are they like global variables?