CONTINUOUS INTEGRATION USING JENKINS

- Vinay Gopalkrishna

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

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

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.

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? ”

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.”

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

CI WORKFLOW

CI WORKFLOW

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

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

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.

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

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

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

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.

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)

ANY QUESTIONS?