Jenkinsfile with custom function for reading a file as environment variables

Jenkinsfile

node {
	stage('Demo') {
		echo "Hello world"
		withConfigEnv('env') {
			echo "Here we go:"
			sh "printenv"
		}
	}
}

// utility function: read file & provide as envionment vars
def withConfigEnv(String configFileId = 'env', Closure body) {
	echo "DEBUG: configFileId=$configFileId"
	configFileProvider([configFile(fileId: 'global.env', variable: 'tempGlobalFile'), configFile(fileId: configFileId, variable: 'tempLocalFile')]) {
	    def globalContent = readFile tempGlobalFile
	    withEnv(globalContent.split("\n")) {
	    	def localContent = readFile tempLocalFile
	    	withEnv(localContent.split("\n")) {
			body()
		}
	    }
	}
}