Jenkinsfile Helpers

credentials.Jenkinsfile

// ** DUMP CREDENTIALS INTO AN ENV VAR **
node {
  def cert="cert-id"
  withCredentials([[$class: 'FileBinding', credentialsId: "${cert}", variable: 'REG_CERT']]) {
    sh 'cat ${env.REG_CERT}' // Maybe don't actually cat it, but there ya go
  }
}

docker.Jenkinsfile

// ** DOCKER BUILD AND PULL FROM A PRIVATE DOCKER HUB REPOSITORY
node {
  def app="example"
  def hub="https://index.docker.io/v1/"
  def hubCreds="credential-ID-here" //You can set via a regular Jenkins credential with username and password
  
  stage 'Docker build'
  docker.withRegistry("${hub}", "${hubCreds}") {
    docker.build("${app}")
    // If you want to pass a specific Dockerfile, then do this
    // docker.build("${app}", "-f custom.Dockerfile .")
  }
}

git-single-pipeline.Jenkinsfile

stage "Checkout" 
git url: 'https://github.com/sample/project', credentialsId: 'your-credentials-here', branch: 'optional-branch'

maven.Jenkinsfile

// ** CUSTOM JAVA AND MAVEN **

// This shows you how to add a custom Java and Maven to your path
// Used this for DC/OS's slaves, which are not provisioned with Maven like the master
// You need to make sure that you specify the version of Java and Maven in the global tool configuration view in Jenkins first

node {
  stage 'Configuration'
  env.JAVA_HOME = "${tool 'JDK 8u101'}" //Swap out JDK 8u101 with whatever is the ID of the Java version you specified
  env.PATH = "${env.JAVA_HOME}/bin:${env.PATH}"
  env.PATH = "${tool 'Maven 3'}/bin:${env.PATH}" //Swap out Maven 3 with Maven ID version
  
  sh 'java -version'
  sh 'mvn -v'
}