This document discusses continuous integration using Jenkins. It defines continuous integration as merging developer work frequently, such as daily, and verifying changes through automated builds and tests. Benefits of CI include early bug detection and improved code quality. The document outlines best practices for CI workflows and describes the key components of builds. It introduces Jenkins as an open source CI tool and explains how it can be used to automate builds, run tests, generate reports, and integrate with version control and other tools through plugins.

1. CONTINUOUS INTEGRATION USING JENKINS
- Vinay Gopalkrishna

2. AGENDA
 Continuous Integration
 What is CI?
 Why we need CI?
 Best Practices
 Workflow
 Build Ingredients
 CI Server – Jenkins
 What is Jenkins?
 How Jenkins work?
 Plugins
 What Jenkins can do?
 Conclusion
 References

3. CI - DEFINED
 Continuous Integration is the practice, in software
engineering, of merging all developer working
copies with a shared mainline several times a day.
 CI is a software development practice where
members of a team integrate their work frequently,
usually each person integrates at least daily –
leading to multiple integrations per day. Each
integration is verified by an automated build
(including test) to detect integration errors as
quickly as possible. – Martin Flower

4. CI – WHAT DOES IT REALLY MEAN?
 At a regular frequency (ideally at every commit), the
system is :
 Integrated
 All changes up until that point are combined into the project
 Built
 The code is compiled into an executable or package
 Tested
 Automated Test suites are run
 Archived
 Versioned and stored so it can be distributed as is, if desired
 Deployed
 Loaded onto a system where the developers can interact with
it.

5. WHY WE NEED CI?
 Fixing bugs late is costly
 Lack of team cohesion
 “Your changes to bar are incompatible with mine. How
do we merge now?”
 “When did we decided to upgrade to version 2.0 of the
super library?”
 “I thought you fixed that 2 months ago!”
 Poor quality code base
 “We have 3 classes doing the same thing!!”
 “Everybody knows double checked locking is bad idea!”
 “Why can’t I just include Foo and not require all of the
other 13 libs? ”

6. WHY WE NEED CI? CONT…..
 Lack of project visibility
 “What do you mean the tests are failing? ”
 “What’s in the version 1.2.3 of the build”
 What’s our code coverage now?
 Lack of deployable software
 “It works on my machine!”
 “I need a new build to test with”
 “The boss|customer is coming, we need to demo
progress asap.”

7. BEST PRACTICES
 Maintain Code Repository
 Automate the build
 Everyone commits the baseline everyday
 Every commit (to baseline) should be built
 Keep the build fast
 Test in the clone of production environment
 Make it easy to get the test deliverables
 Everyone can see the results of the latest build
 Automate deployment

8. CI WORKFLOW

9. CI WORKFLOW

10. BUILD INGREDIENTS
 Compilation
 Ensures code actually compiles
 On every target platform
 Test execution
 Ensures product functions as expected
 Through repeatable testing
 Database integration
 Ensures DB and code is in sync
 Automates (re)creation of test data

11. BUILD INGREDIENTS SOME MORE
 Code inspection
 Ensures a healthy code base
 Identifies problems early
 Enforces best practices
 Automated deployment
 Products can be released anytime
 Continually demo-able state
 Eliminates “Works on my machine”
 Documentation generation
 Ensures document is current
 Removes burden from developers
 Produces build reports and metrics

12. CI SERVER - JENKINS
 It is an open source CI tool written in java.
 It is a server based system running in a servlet
container.
 It supports SCM tools including Accurev, CVS,
Subversion, Git, Mercurial, Perforce, Clearcase.
 It can execute Apache Ant and Apache maven
based projects.
 Builds can be started by various means, including
being triggered by commit in version control
system.

13. HOW JENKINS WORK - SETUP
 When setting up a project in Jenkins, out of the box
you have the general options
 Associating with a version control server
 Triggering builds
 Execution of shell scripts, bash scripts, Ant targets and
maven targets.
 Artifact archival
 Publish jUnit test results and javadocs
 Email Notifications

14. PLUGINS
 Jenkins plugin system can enable a wide range of
features including(but not certainly not limited to)
 SCM
 Testing
 Notifications
 Reporting
 Artifact saving
 Triggers
 External integration
 And most importantly – The CI game
 A points based game where developers compete against each
other to develop the most stable, well tested code

15. WHAT JENKINS CAN DO?
 Generate Test Reports
 Integrate with many different version control
systems
 Push to various artifact repositories
 Deploys directly to production or test environments
 Notify stakeholders of build status

16. CONCLUSION
 Continuous Integration is a necessity on complex
projects due to the benefits it provides regarding
early detection of problems.
 A good continuous build system should be flexible
enough to fit into pre-existing development
environments and provide all the features a team
expects from such a system.
 Jenkins, a continuous build system, can be an
integral part of any continuous integration system
due to its core feature set and extensibility through
a plugin system.

17. REFERENCES
 Continuous integration
 http://en.wikipedia.org/wiki/Continuous_integration
 http://java.dzone.com/articles/continuous-integration-
how-0
 Jenkins
 http://en.wikipedia.org/wiki/Jenkins_(software)

18. ANY QUESTIONS?