how to create loop inside jenkinsfile

Question

i have created a jenkinsfile inside i have created a text parameter with 10 server names. i want to create a loop within a stage to echo each server name.

// ######################################################################### PROPERTIES ###########################################################################

properties([
    parameters([
        text(defaultValue: '', description: 'EXAMPLE:   lsch3-123', name: 'SERVERS')])])

// ######################################################################### START PIPELINE ###########################################################################

pipeline {
    agent none
    options {
        skipDefaultCheckout true
    }
    stages {
        stage('GIT & PREP') {
            agent {label "${params.DC}-ansible01"}
            steps {
                cleanWs()
                run loop here
            }
        }
    }
}

Answer 1

Please see below code/reference example which will loop within the stage.

// Define list which would contain all servers in an array. Initialising it as empty
def SERVERS = []
pipeline {
    agent none
    options {
        skipDefaultCheckout true
    }
     parameters
    {
        // Adding below as example string which is passed from paramters . this can be changed based on your need
        // Example: Pass server list as ; separated string in your project. This can be changed 
        string(name: 'SERVERS', defaultValue:'server1;server2', description: 'Enter ; separated SERVERS in your project e.g. server1;server2')
    }
    stages {
        stage('GIT & PREP') {
            agent {label "${params.DC}-ansible01"}
            steps {
                cleanWs()
                // run loop here under script 
                script
                {
                    // Update SERVERS list.Fill SERVERS list with server names by splitting the string.
                    SERVERS = params.SERVERS.split(";")
                    // Run loop below : execute below part for each server listed in SERVERS list
                    for (server in SERVERS)
                    {
                        println ("server is : ${server}") 
                    }
                }
            }
        }
    }
}

Regards.