A quick script to get the # of builds in the "Build Queue" - i.e., the number of builds which are awaiting an open Executor slot - in Jenkins.

build.gradle

apply plugin: 'java'
apply plugin: 'maven'
apply plugin: 'groovy'

repositories {
    mavenCentral()
}

dependencies {
	compile 'org.codehaus.groovy:groovy-all:2.3.8'
	compile 'org.codehaus.groovy.modules.http-builder:http-builder:0.7'
}

task getBuildCount (dependsOn: 'classes', type: JavaExec) {
    main = 'getBuildCount'
    classpath = sourceSets.main.runtimeClasspath
}

getBuildCount.groovy

import groovyx.net.http.RESTClient

def client = new RESTClient('http://jenkins:someport' )
println getAwaitingBuildCount(client)

int getAwaitingBuildCount(RESTClient client){
  def resp = client.get( path : '/queue/api/json' )
  return resp.data['items'].size()
}

NOTE: getBuildCount.groovy needs to be in src/main/groovy to work with this gradle file (Gist won't let me indicate path on the filename.)

TODO: Merge this function into http://github.com/bryantrobbins/jenkinsutils

TODO: Show how to add auth to this.

Jenkins Remote API docs are here. If you haven't looked or tried something in a while, it's constantly improving (because opensource):

https://wiki.jenkins-ci.org/display/JENKINS/Remote+access+API