Extending Jenkins: Get a complete walkthrough of the many interfaces available in Jenkins with the help of real-world examples to take you to the next level with Jenkins

Table of Contents

Extending Jenkins

Credits

About the Author

About the Reviewer

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Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Preparatory Steps

Getting started with Jenkins

Extending the basic setup

Jenkins evolution

Continuous Integration with Jenkins

Summary

2. Automating the Jenkins UI

Use case scenario 1 – a large number of jobs

Use case scenario 2 – multiple hosts

Use case scenario 3 – helping your users through UI automation

Use case scenario 4 – UI tweaks

Summary

3. Jenkins and the IDE

Eclipse and Mylyn

Installing Mylyn

Mylyn and Jenkins configurations

IntelliJ IDEA and Jenkins build connectors

NetBeans

Summary

4. The API and the CLI

Creating an Information Radiator with the Jenkins XML API

Getting the information from Jenkins

Automating the job

Radiating the information

Jenkins as a web server – the userContent directory

The Jenkins CLI

How to set it up

How to use it

Triggering remote jobs via the CLI

Updating Jenkins configuration

Summary

5. Extension Points

A brief history of Jenkins plugins

Interfaces

Abstract classes

Abstraction and interfaces

Singletons

Declaring an extension in Jenkins

Summary

6. Developing Your Own Jenkins Plugin

An introduction to Maven

Installing Maven

Summary

7. Extending Jenkins Plugins

Where to start?

Looking at the list of existing plugins

A new build type required

Loading and building our starting point

The Builder class and Stapler

Jelly and Jenkins

Help

Properties files and Messages

The POM file

Plugin progress

Summary

8. Testing and Debugging Jenkins Plugins

Running tests with Maven

Debugging Jenkins

Server debugging – a quick recap

Debugging with IntelliJ

Debugging with Eclipse

mvnDebug

The Jenkins Logger Console

Summary

9. Putting Things Together

The Jenkins script console and Groovy

Groovy and Gradle as alternatives

Jenkins and Docker

Docker in Jenkins

Jenkins in Docker

Jenkins and Android

Jenkins and iOS

Keeping your Jenkins version and plugins up to date

Summary

Index

Extending Jenkins

Extending Jenkins

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: December 2015

Production reference: 1171215

Published by Packt Publishing Ltd.

Livery Place

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Birmingham B3 2PB, UK.

ISBN 978-1-78528-424-3

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Credits

Author

Donald Simpson

Reviewer

Tony Sweets

Commissioning Editor

Amarabha Banerjee

Acquisition Editor

Indrajit Das

Content Development Editor

Riddhi Tuljapurkar

Technical Editor

Menza Mathew

Copy Editor

Kausambhi Majumdar

Project Coordinator

Sanchita Mandal

Proofreader

Safis Editing

Indexer

Tejal Daruwale Soni

Graphics

Abhinash Sahu

Production Coordinator

Melwyn Dsa

Cover Work

Melwyn Dsa

About the Author

Donald Simpson is an information technology consultant based in Scotland, UK.

He specializes in helping organizations improve the quality and reduce the cost of software development through the adoption of process automation and Agile methodologies.

Starting out as a Java developer, Donald's interest in application servers, networking, and automation led him to a career as a build engineer. He remains highly technical and hands-on and enjoys learning about new technologies and finding ways to automate and improve manual processes.

He can be reached at www.donaldsimpson.co.uk.

I would like to thank my wife, Clair, and my children, Freya and Lyla, for their support and encouragement throughout my career and the writing of this book.

About the Reviewer

Tony Sweets has over 20 years of experience in software development, with most of it in Java and Java-based technologies. Known as the Tools guy before there was any concept of DevOps, he also has a passion for setting up and managing hardware and networks. Introduced to Agile development very early on, he has set up and maintained his company's continuous integration system that ranges from Cruise Control to Hudson, and now Jenkins. He is currently a software architect in the payments field and has been working in financial services for over 17 years.

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Preface

Jenkins provides many interfaces and extension points to enable users to customize and extend its functionality. In this book, we will explore these interfaces in depth and provide practical real-world examples that will take your usage of Jenkins to the next level.

In this book, you will learn how to develop and test your own Jenkins plugin, find out how to set up fully automated build pipelines and development processes, discover how to interact with the API and CLI, and how to enhance the user interface.

What this book covers

Chapter 1, Preparatory Steps, will cover the initial setup steps—getting your development environment set up, an overview of Jenkins and some options to install and run it as well as extend the basic setup. We will also review the principles of Continuous Integration, which are explored in greater detail later.

Chapter 2, Automating the Jenkins UI, will discuss how several common issues and bottlenecks may be alleviated through the automation and adaptation of the Jenkins frontend. Here, we will look at four fairly typical use cases, identify the root cause of the issues, and propose some possible improvements that can be made through the alteration and automation of the GUI.

Chapter 3, Jenkins and the IDE, builds on the Continuous Integration principals that we looked at earlier and provides an introduction to the Mylyn project.

It then details how to set up a process that enables developers to interact with Jenkins directly from within their IDE. A selection of examples covers Eclipse, NetBeans, and IntelliJ.

Chapter 4, The API and the CLI, illustrates how we can automate and extend Jenkins through its API and CLI. In this chapter, we will illustrate how to use these interfaces by working through the high-level building blocks of an example Information Radiator project.

This chapter will explain how to create a dynamic application that consumes information from Jenkins via its exposed interfaces.

We will also review other ways in which you could extend Jenkins via the CLI—by kicking off jobs and making other changes to Jenkins automatically and remotely.

Chapter 5, Extension Points, introduces many important concepts that provide a foundation for the Jenkins Extension points topics in the subsequent chapters. We will run through Java interfaces, Design by Contract, abstract classes, and Singletons. We will then take a look at how these patterns are used in the real world when we define our own Extension Point in Jenkins.

Chapter 6, Developing Your Own Jenkins Plugin, will combine the skills, concepts, and tools from the preceding chapters to build our first Jenkins plugin.

We will take a look at Maven and learn how to set it up and use it for Jenkins plugin development. We will then create our first Jenkins plugin, learn how to install it locally, and then learn how to quickly make, build, and deploy subsequent changes using Maven.

Chapter 7, Extending Jenkins Plugins, makes use of a simple plugin with the Hello world functionality we created in the previous chapter to keep the focus on getting to grips with the processes and tools. This chapter takes a look at the best way to get started with adding your own implementations. You will learn how to reuse existing code and functionality and understand how and where to find them.

After taking a look at