how to run a complete Jenkins scripted pipeline stage from shared libraries src file

Question

I recently started with Jenkins shared libraries in Jenkins pipeline. I created a "func.groov" class and located it under "src/org/prj/func.groovy" :

package org.prj
import jenkins.model.
class func implements Serializable {
 def steps 
 func(steps) {
  this.steps = steps
 }
 def sh(args) {
  steps.sh "echo ${args}"
 }
 def setLBL(CurrentNodeName,newLabelName){
   jenkins.model.Jenkins.instance.slaves.each{ slave ->
     if (slave.getNodeName() == CurrentNodeName){
       slave.setLabelString(newLabelName)
     }
  }
} 

Jenkinsfile (scripted) looks like:

@Library('prj') import org.prj.func
def utils = new func(steps)
node(lbl)
{
  stage("A"){
     Build_node_lbl = env.NODE_NAME+System.currentTimeMillis()
     utils.setLBL(env.NODE_NAME,Build_node_lbl)

   }
}

so currently it works. my question is how to create a full stage (like "A") as a function in func.groovy shared lib which will include, for example:

1. GIT checkout step
2. sh compilation step
3. Artifactory deploy step

Im actually looking to create a "building blocks" (a "Build" in my example) with Jenkins pipeline and shard libraries.

Answer 1

1. With Class Instantiation

You can create a class like you would do in Java. Then in your Jenkinsfile you instantiate the class and call its function.

src/org/prj/MyPipeline.groovy:

package org.prj

class MyPipeline {

  def steps

  MyPipeline(steps) {this.steps = steps}

  public def build() {
    steps.node('lbl') {
      steps.stage('A') {
        // Do build stuff
        // steps.sh(..)
      }
    }
  }
}

Jenkinsfile:

import org.prj.MyPipeline

def pipeline = new MyPipeline(this)
pipeline.build()

2. With Static Functions

You may also work with static contexts, without instantiation. However, this would require to hand over the caller context to the pipeline:

src/org/prj/MyPipeline.groovy:

package org.prj

class MyPipeline {

  public static def build(caller) {
    caller.node('lbl') {
      caller.stage('A') {
        // Do build stuff
        caller.sh(..)
      }
    }
  }
}

Jenkinsfile:

import org.prj.MyPipeline

MyPipeline.build(this)