useful Jenkins groovy functions

pipeline.groovy

// find the last successfull build
// you may need to enable these script approvals:
//method hudson.model.Job getBuildByNumber int
//method hudson.model.Job getBuilds
//method hudson.model.Job getLastBuild
//method hudson.model.Job getLastSuccessfulBuild

def lastGreen() {
    def buildName = Jenkins.instance.getItemByFullName("my_great_job")
    if (buildName) {
        return buildName.getLastSuccessfulBuild().getNumber().toString()
    }
    return 1
}
 
// find which EC2 slave is running this job
def whereIam(){
   sh "wget -qO- 169.254.169.254/2019-10-01/meta-data/hostname"
}

// send to Slack the job completion status
def slackMsg(status) {
    color = ''
    message = ''
    switch (status) {
        case "success":
            color = "#00FF00"
            message = "${env.JOB_NAME} Successful"
            break
        case "failed":
            color = "#EE0000"
            message = ":fire: ${env.JOB_NAME} FAILED! :fire:"
            break
    }
}

// enable these methods:
// method hudson.model.AbstractItem setDescription java.lang.String
// staticMethod org.codehaus.groovy.runtime.EncodingGroovyMethods encodeBase64 byte[]
def setAuth(){
   s = "$USER:$PWD"
   auth_token = s.bytes.encodeBase64().toString()
   return auth_token
}

// add a sleep on the current task
def Sleep(){
    Random random = new Random()
    Thread.sleep(random.nextInt(30)*1000) 
} 

// don't run the build if a specific commit message is present
def IgnoreCommittedMessage() {
    def Check = sh(script: "git log -n 1 --oneline| grep 'do not build' |wc -l", returnStdout: true).toInteger()
    if (Check == 1) {
        currentBuild.result = 'NOT_BUILT'
        error("Skipping build")
    }
}

//plus remember you can use
// def fileContents = readJSON file:'list.txt'
// writeJSON file: 'list.txt', json: jsonOut