Jenkins pipeline (parallel && dynamically)

Jenkinsjenkins-pipeline

Question

I have simple parallel pipeline (see code) which I use together with Jenkins 2.89.2. Additionally I use parameters and now want to be able to in-/decrease the number of deployVM A..Z stages automatically by providing the parameter before job execution.

How can I dynamically build my pipeline by providing a parameter?

Researched so far:

Code

The pseudo code of what I want – dynamic generation:

pipeline {

    agent any

    parameters {
        string(name: 'countTotal', defaultValue: '3')
    }

    stages {

       stage('deployVM') {

        def list = [:]
        for(int i = 0; i < countTotal.toInteger; i++) {
            list += stage("deployVM ${i}") {
                steps {
                    script {
                        sh "echo p1; sleep 12s; echo phase${i}"
                    }

                }
            }
        }

        failFast true
        parallel list
       }

   }

}

The code I have so far – executes parallel but is static:

pipeline {

    agent any
    stages {

       stage('deployVM') {
        failFast true
        parallel {
            stage('deployVM A') {
                steps {
                    script {
                        sh "echo p1; sleep 12s; echo phase1"
                    }

                }
            }
            stage('deployVM B') {
                steps {
                    script {
                        sh "echo p1; sleep 20s; echo phase2"
                    }

                }
            }
        }
       }

   }

}

Best Answer

Although the question assumes using declarative pipeline I would suggest to use scripted pipeline because it's way more flexible.
Your task can be accomplished this way

properties([
    parameters([
        string(name: 'countTotal', defaultValue: '3')
    ])
])

def stages = [failFast: true]
for (int i = 0; i < params.countTotal.toInteger(); i++) {
    def vmNumber = i //alias the loop variable to refer it in the closure
    stages["deployVM ${vmNumber}"] = {
        stage("deployVM ${vmNumber}") {
            sh "echo p1; sleep 12s; echo phase${vmNumber}"
        }
    }
}

node() {
    parallel stages
}

Also take a look at snippet generator which allows you to generate some scripted pipeline code.

Related Topic