Have Jenkins Fail Fast When Node Is Offline

I ended up creating this solution which has worked well. The first build step of SubJob01 is an Execute system Groovy script, and this is the script:

import java.util.regex.Matcherimport java.util.regex.Patternint exitcode = 0println("Looking for Offline Slaves:");for (slave in hudson.model.Hudson.instance.slaves) { if (slave.getComputer().isOffline().toString() == "true"){ println('  * Slave ' + slave.name + " is offline!");   if (slave.name == "Slave01") {     println('    !!!! This is Slave01 !!!!');     exitcode++;   } // if slave.name  } // if slave offline} // for slave in slavesprintln("\n\n");println "Slave01 is offline: " + hudson.model.Hudson.instance.getNode("Slave01").getComputer().isOffline().toString();println("\n\n");if (exitcode > 0){ println("The Slave01 slave is offline - we can not possibly continue...."); println("Please contact IT to resolve the slave down issue before retrying the build."); return 1;} // ifprintln("\n\n");

The jenkins pipeline statement 'beforeAgent true' can be used in evaluating the when condition previous to entering the agent.

    stage('Windows') {      when {        beforeAgent true        expression { return ("${TARGET_NODES}".contains("windows")) }      }      agent { label 'win10' }      steps {        cleanWs()        ...      }

Ref:

• https://www.jenkins.io/doc/book/pipeline/syntax/
• https://www.jenkins.io/blog/2018/04/09/whats-in-declarative/