Load properties from properties file and make them available throughout the job/pipeline - Jenkins declarative syntax

Question

My requirement is simple, i just want to externalize some 'values' to make my Jenkinsfile more re usable and for this i need to load the properties from a file which is going to be right next to Jenkinsfile, and make sure that these properties are available anywhere in the pipeline. I am still new to groovy and Jenkins code but never thought such a simple thing would be so difficult. I enabled some methods in script security plugin but the following code (and several variations i tried around it) always pose errors or print null or give me NPE. I have tried multiple combinations and the below code is just one of them.

properties = null

@NonCPS
def loadProperties() {
    checkout scm
    File propertiesFile = new File('${workspace}/pipeline.properties')
    propertiesFile.withInputStream {
            properties.load(propertiesFile)
    }
}

pipeline {
    agent none

    stages {

        stage ('prepare') {
            agent any

            steps {
                script {
                loadProperties()
                echo "${properties['repo']}"
                }
            }
        }
        stage('Build') {

            agent any

            steps {
                sh 'echo ${properties.repo}'
            }

        }
    }
}

Answer 1

I figured out a couple of ways to externalize properties in Jenkins pipelines. You can choose your pick based on the main difference.

1) Using groovy code entirely. This code snippet would require you to enable several method signatures in 'In-process script approval' which comes in with script security plugin, and hence this should be done only after due consideration.

properties = null     

def loadProperties() {
    node {
        checkout scm
        properties = new Properties()
        File propertiesFile = new File("${workspace}/pipeline.properties")
        properties.load(propertiesFile.newDataInputStream())
        echo "Immediate one ${properties.repo}"
    }
}

pipeline {
    agent none

    stages {
        stage ('prepare') {
            agent any

            steps {
                script {
                    loadProperties()
                    echo "Later one ${properties.branch}"
                }
            }
        }
        stage('Build') {
            agent { label 'master'  }

            steps {
                // works fine. properties is available everywhere
                echo properties.branch
            }           
        }
    }
}

2) Using pipeline utility steps plugin - Pipeline suite of plugins include this by default and it allows a better way to load properties without requiring to enable security exceptions. I would recommend this method.

properties = null

def loadProperties() {
    node {
        checkout scm
        properties = readProperties file: 'pipeline.properties'
        echo "Immediate one ${properties.repo}"
    }
}

pipeline {
    agent none

    stages {           
        stage ('prepare') {
            agent any

            steps {
                script {
                    loadProperties()
                    echo "Later one ${properties.ansible}"
                }
            }
        }
        stage('Build') {

            agent any

            steps {
                echo properties.branch
            }

        }
    }
}