Jenkins is a tool that supports continuous integration by automatically building, testing, and deploying code changes. It integrates code changes frequently, at least daily, to avoid "big bang" integrations. Jenkins runs builds and tests across multiple platforms using slave nodes. It supports various source control systems and build tools and notifies developers of failed builds or tests through email or other plugins.

1. Continuous Integration with Jenkins CI
Jan Riemann und Niklas Lochschmidt

2. Late Integration is… not good
Can Lead to “Big Bang Integration”
External Project
Master
Integration Deliverable
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 2

3. Continuous Integration
External Project
Master
§ A software development practice
§ Integrate your work in the project as often as possible
§ At least once a day Deliverable
§ Integration goes alongside the development à continuous
§ Integration is no longer a dreadful (often postponed) event Integration
§ Only possible through automated builds, tests and deployment
§ Leads to better quality and early deliverables
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 3

4. CI Best Practices
§ Maintain a single source repository
§ One team has one repository holding the mainline (trunk)
§ Checkout must include everything needed for the build
§ Automate the build
§ Use a script or a build tool (e.g. Maven)
§ Manage dependencies
§ Make the build fast
§ Show all warnings and errors
§ Fail early
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 4

5. CI Best Practices
§ Make your build self-testing
§ Run tests as part of the build process
§ Provide rapid feedback Integration
§ define a test pipeline with distinct test phases Tests
§ Test in the production clone Unit Tests
Static Code Analysis
§ Automate deployment
§ Always publish the latest tested build
§ Everyone has the same state
§ Could go directly in production (not recommended)
à Automate the entire setup using
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 5

6. What is Jenkins CI?
§ Jenkins is a central build server
§ Written in Java
§ Runs as Servlet in Tomcat or standalone (e.g. Windows Service)
§ Performs „jobs“
§ Configurable
§ Does all the tedious work (checkout, build, test, package, deploy)
§ Adapts to your workflow
§ More than 350 plugins available
§ Jenkins forked from Hudson (Oracle) in January 2011
§ Most Hudson developers switched to Jenkins
§ Oracle donated Hudson to the Eclipse Foundation in May 2011
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 6

7. Repository Contains Everything Needed to
Build the Project
§ CI: Repository contains:
§ Code, Resources
§ NO build products
§ Jenkins supports many common SCM systems like SVN, CVS
§ Automatic checkout/update on build
§ Build on updates in the SCM
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 7

8. Building the Project Relies on External Build
Tools
§ Jenkins relies on external build
tools
§ Many common tools supported -
like Ant, Maven, Ivy (plugins), …
§ Allows to reuse the build scripts
used locally
§ Jenkins builds the project…
§ after another project has been
builded
§ according to a given schedule
§ after code changes in the SCM
§ many other (=> Plugins)
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 8

9. Jenkins Allows to Perform Post-Build Actions
§ If build fails, Jenkins considers job as failed
§ Jenkins allows to perform a number of post-build actions:
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 9

10. Common Test-Frameworks are Supported by
Jenkins
§ Jenkins can use all test frameworks supported by the build tool
§ Has plugins to read and visualize the test results of various frameworks
§ Junit, Checkstyle, Findbugs, Selenium, coverage tools,...
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 10

11. Multiple Test-Sets can be Executed using Jobs
§ Multiphase testing
§ Small tests can be executed after each SCM commit giving fast feedback
§ Time consuming tests can be executed on a nightly basis (e.g. Selenium FF)
§ One job for each set of tests
§ CI: Tests should also happen in a production system clone
§ Tests fail: Jenkins considers project as unstable
§ Otherwise: successfull
§ Keeps history of build status
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 11

12. Jenkins Supports Automatic Deployment
§ Jenkins offers (again) a lot of possibilities to deploy generated artifacts
§ Upload to scm, ftp, folder, …
§ Ideally, the output of a build cycle is a fully running artifact
§ Can serve as a common basis for all developers
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 12

13. Sources
§ Continuous Integration
§ http://martinfowler.com/articles/continuousIntegration.html
§ http://www.se-radio.net/?s=133
§ Jenkins
§ Homepage http://www.jenkins-ci.org
§ Wiki http://wiki.jenkins-ci.org
§ Plugin-List https://wiki.jenkins-ci.org/display/JENKINS/Plugins
§ Github https://github.com/jenkinsci/jenkins
§ Jenkins CI Server http://ci.jenkins-ci.org/
§ Fork from Hudson http://jenkins-ci.org/content/hudsons-future
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 13

14. Get Notified about Failed Builds and Failed
Tests
§ Via Email (Default) or...
...
http://www.pragmaticautomation.com/cgi-bin/pragauto.cgi/Monitor/Devices/BubbleBubbleBuildsInTrouble.rdoc
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 14

15. Integration in Eclipse
§ „Mylyn Builds Connector: Hudson/Jenkins“ in the Mylyn repository
§ Update-Site: http://download.eclipse.org/mylyn/releases/latest
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 15

16. Jenkins Supports Multi-Environment Builds
§ Multi-environment builds
§ Easy to automatically build (and test) the project on many platforms using
slaves
§ Multiplatform testing
§ Jenkins slaves can execute the testsuite on different platforms
08. Juni 2011 | Component Technology for Distributed Applications | Niklas Lochschmidt, Jan Riemann 16