List all Jenkins jobs and count build duration for each in sum for a period of time

script.groovy

def daysBefore = 30
def currentMillis = System.currentTimeMillis()

def cutOfDate = System.currentTimeMillis() - 1000L * 60 * 60 * 24 * daysBefore

long sumDurationMillis = 0

for (job in Jenkins.instance.getAllItems(Job.class)) {
  	def job_name = job.getFullName()
  	long durationMillis = 0
	builds = job.getBuilds().byTimestamp(cutOfDate, currentMillis)

	builds.each { build -> 
    	durationMillis+= build.duration
	}
  	println("$job_name --> $durationMillis")
  	sumDurationMillis += durationMillis 
}


def sumDurationMinutes = sumDurationMillis / 1000 / 60

println "\nsumDurationMillis --> $sumDurationMillis"
println "sumDurationMinutes --> $sumDurationMinutes"