Jenkins-pipeline Extract and Set variables from properties file in groovy

Question

To begin i'm writing the pipeline entirely as groovy to be checked in to git. Please do not provide any gui necessary solutions. My Problem statement is:

Extract a variable from a file and set it equal to a groovy object.

What i've tried

def SERVICE_MAJOR_VERSION
node {
    runGitClone(GIT_REPO_URL, GIT_HASH)
    def conf = readFile("gradle.properties")
    echo conf
    //THE BELOW COMMENT DOESN'T WORK
    //SERVICE_MAJOR_VERSION = loadEnvFromFile("SERVICE_VERSION_MAJOR", "gradle.properties", true, SERVICE_VERSION_MAJOR)
}    

def runGitClone(git_repo_url, git_hash) {
    checkout changelog: false, poll: false, scm: [$class: 'GitSCM', branches: [[name: git_hash]], doGenerateSubmoduleConfigurations: false, extensions: [[$class: 'WipeWorkspace']], submoduleCfg: [], userRemoteConfigs: [[credentialsId: '85572032-4284-4095-9eec-4df70ddfdb68', url: git_repo_url]]]
}

def loadEnvFromFile(string_name, file_path, should_print_load) {
    def par1 = null
    def content = readFile file_path
    def matcher = content =~ /${string_name}\=(.+)/
    if (matcher) {
        par1 = string_name + "='" + matcher[0][1] + "'"
        new GroovyShell(this.binding).evaluate(par1)
            if (should_print_load) {
            println par1
        }
    }
    return par1
}

I've tried other suggestions to no avail. Particularly the below two.

• Get values from properties file using Groovy
• Parsing string as properties

If you have a working example of extracting a variable from a file and setting it equal to a groovy object it would solve my problem.

Answer 1

SOLVED:

def content = readFile 'gradle.properties'

Properties properties = new Properties()
InputStream is = new ByteArrayInputStream(content.getBytes());
properties.load(is)

def runtimeString = 'SERVICE_VERSION_MINOR'
echo properties."$runtimeString"
SERVICE_VERSION_MINOR = properties."$runtimeString"
echo SERVICE_VERSION_MINOR