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Jenkins Snippets

Ignorable Preface

One of my tasks at work was to prevent builds aborted by kill_outdated_builds() from resuming upon a Jenkins restart. After I finished that one, I got a task later to remove all unsafe method usages, mainly the use of getRawBuild which was used beyond the aforementioned function. It is used liberally on StackOverFlow, which is unfortunate, as if a public repository decides to use the function, there will be a massive security hole.

These two snippets are a safe but rather unintuitive way to abort builds and get the build log in Jenkins. They took hours of research just to figure out and implement.

Aborting Old / Outdated Builds

import hudson.model.ParametersAction
import jenkins.model.Jenkins
import jenkins.model.CauseOfInterruption
import jenkins.model.Jenkins
// type of _build in case you need it
import org.jenkinsci.plugins.workflow.job.WorkflowRun

// TODO: create plugin or something for custom status messages

@NonCPS
def abortOldBuilds(String paramKey, String paramVal) {
    // param_key and paramVal can be used for PR numbers
    def job = Jenkins.instanceOrNull.getItem(JOB_NAME)
    def buildID = BUILD_ID
    // highest running ID
    def highestRID = buildID
    // in case the current build is old
    WorkflowRun curBuild

    def build = job.getLastBuild()
    // avoid .builds since it can cause iteration errors
    while (build != null) {
        def cbuildID = build.id.toInteger()
        def curParamVal = build.allActions.find{it in ParametersAction}?.getParameter(paramKey)?.value
        // optionally filter out builds
        if (curParamVal == param_val) {
            if (cbuildID == buildID) {
                curBuild = build
            } else if (build.isBuilding() && cbuildID < highestRID) {
                build.doKill()
                echo "terminated build #${cbuildID}"
                def cause = "Aborted by #${buildID} for being an old build" // + for paramVal
                // add to the log of another build
                build.getListener().getLogger().println(cause)
                // The below will cause zombie jobs and so was abandoned
                // def r = new ArrayList<>(Arrays.asList({ cause as String } as CauseOfInterruption))
                // _build.addAction(new InterruptedBuildAction(r))
            } else if (cbuildID > highestRID) {
                // update highest running ID
                highestRID = cbuildID
            }
        }
        build = build.getPreviousBuild()
    }
    if (highestRID > buildID) {
        println "Terminating self since newer build was found"
        def selfAbortCause = "Aborting due to the presence of a newer build"
        curBuild.doKill()
    }
}

Getting Build Log

import jenkins.model.Jenkins

@NonCPS
def getLog() {
    def job = Jenkins.instanceOrNull.getItem(JOB_NAME)
    def build = job.getBuildByNumber(Integer.parseInt(BUILD_NUMBER))
    return build.logFile.text
}