[SOLVED] How to access Shell variable value into Groovy pipeline script

Issue

Right now I am a newbie for Shell, Jenkins, Groovy pipeline. My requirement is I am reading file text into a variable under shell script and I need to pass this variable value out of shell script and to use in Groovy script.

Here is my code:

stages
    {
        stage('example')
        
        {
            steps
            {
                script
                {
                    
                sh'''
                    #!/bin/bash
                    set +x                  
                    readVal=$(<$WORKSPACE/test.json)
                    echo "$readVal"        //this is priting my entire json successfully                  
                    
                  echo 'closing shell script'
                    
                ''' 
                    
                    
                    println WORKSPACE    /// this is printing my workspace value successfully 
                    
                    println readVal     // not working 
                    println env.readVal     // not working 
                    println $readVal     // not working 

                
                }
            }
        }
    }

How to get readVal's value out of shell to access?

Solution

See Jenkins, Pipeline Best Practices:

a. Solution: Instead of using [a complex function], use a shell step and return the standard out. This shell would look something like this:

def JsonReturn = sh label: '', returnStdout: true, script: 'echo "$LOCAL_FILE"| jq "$PARSING_QUERY"'

Example

pipeline {
    agent any

    stages {
        stage('example') {
            steps {
                script {
                    def readVal = sh script: 'echo "READ_VAL_VALUE"', returnStdout: true
                    echo readVal
                    println readVal
                }
            }
        }
    }
}

Console Output

[Pipeline] Start of Pipeline
[Pipeline] node
Running on Jenkins in C:\Users\jenkins\AppData\Local\Jenkins\.jenkins\workspace\Pipeline project
[Pipeline] {
[Pipeline] stage
[Pipeline] { (example)
[Pipeline] script
[Pipeline] {
[Pipeline] sh
+ echo READ_VAL_VALUE
[Pipeline] echo
READ_VAL_VALUE

[Pipeline] echo
READ_VAL_VALUE

[Pipeline] }
[Pipeline] // script
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
Finished: SUCCESS

Answered By - Gerold Broser