Get top n bytes from the last change log using Groovy PostBuild

GetLastChangeLogfromGroovyPostBuild.groovy

import hudson.FilePath;

// Size(in byte) of log that you want to display.
def logLength = 400

def myBuildStatus = manager.build.result.toString()
//manager.listener.logger.println("$myBuildStatus");
//manager.logContains("^Build FAILED.")

if(myBuildStatus == "SUCCESS") {
    return
}

def myWorkdSpace = manager.envVars["WORKSPACE"]
//manager.listener.logger.println("${myWorkdSpace}");
//def myJobName = manager.build.project.name
//manager.listener.logger.println("${myJobName}");
//def item = hudson.model.Hudson.instance.getItem("myJobName") 
//def myNodeName = manager.build.getBuiltOn().getNodeName()
//manager.listener.logger.println("${myNodeName}");

// This is required when you want access workspace in the groovy postbuild
channel = manager.build.workspace.channel
manager.listener.logger.println("$channel");

def files = buildFileList(myWorkdSpace)
def buildFileList(dirname) {
    def files = [:]
    def dir = new hudson.FilePath(channel, dirname)
    //manager.listener.logger.println("$dir");

    if( dir.directory ) {
        dir.list().each {
            //manager.listener.logger.println("$it");
            def path = it.toString()
            if( it.directory ){
                files << buildFileList(path)
            } else if ( path.matches('.+\\.log') ) {
                //manager.listener.logger.println("$path");
                def myTimeStamp= new hudson.FilePath(channel, path).toVirtualFile().lastModified()
                files[path] = myTimeStamp
            }
        }
    }
    return files
}

manager.listener.logger.println("Discovered ${files.size()} files:")

def modifiedTime = 0
def newestModified

files.each { filename, modified ->
    if(modified > modifiedTime) {
      modifiedTime = modified
      newestModified = filename
    }
    //manager.listener.logger.println("${filename}' '${modified}' found")
}

if(newestModified) {
    manager.listener.logger.println("############################################################")
    manager.listener.logger.println("Last modified log file is $newestModified")
    manager.listener.logger.println("############################################################")
    
    def myLogSize = 0
    def totalLogSize = new hudson.FilePath(channel, newestModified).length()
    if(  totalLogSize <= logLength ){
        myLogSize = totalLogSize
    } else {
        myLogSize = totalLogSize - logLength
    }
    def myLog = new hudson.FilePath(channel, newestModified).readFromOffset(myLogSize)
    manager.listener.logger.println("$myLog")

    manager.listener.logger.println("############################################################")
    manager.listener.logger.println("End of Last modified log file")
    manager.listener.logger.println("############################################################")
    manager.listener.logger.println("")
}