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A presentation given by me on CI in Aftek
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Continuous Integration: Improving Software Quality and Reducing Risk
Preetam PalweAftek Limited
One more title
Do you love bugs ?Or
Are you in love with QC members?
… [Courtesy: Smita N]
Agenda
Motivation Practices Advantages The road ahead Q&A
Motivation “Enter laptops, enter boards and put together with
code, all teams have come together in one abode. Integration in progress.” … taken from an article published in AForce March 2008
Admin Utility User now can be associated with the profile and action like
send sms, call to a specific person or play welcome message on entering in the home.
The UI part for above feature is implemented by XYZ. And backend part is implemented by PQR. Integration of the same is pending and will integrate on next week.
… taken from an weekly status report sent in 1st week of March 2008
So ???
Motivation Integration is an EVENT !!!
Can we have something like following?
Image Courtesy: Book on CI by PMD
What is CI? Continuous Integration 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. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly.
… taken from Martin Fowlers article on CI
Agile manifesto Individuals and interactions <OVER>
processes and tools Working software <OVER> comprehensive
documentation Customer collaboration <OVER> contract
negotiation Responding to change <OVER> following a
plan
That is, while there is value in the items on the right, we value the items on the left more.
Agile principles1. Our highest priority is to satisfy the customer through
early and continuous delivery of valuable software.2. Welcome changing requirements, even late in
development. Agile processes harness change for the customer's competitive advantage.
3. Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter time scale.
4. Business people and developers must work together daily throughout the project.
5. Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.
Agile principles (contd)6. The most efficient and effective method of conveying
information to and within a development team is face-to-face conversation.
7. Working software is the primary measure of progress.8. Agile processes promote sustainable development.9. The sponsors, developers, and users should be able to
maintain a constant pace indefinitely.10. Continuous attention to technical excellence and good
design enhances agility.11. Simplicity—the art of maximizing the amount of work
not done—is essential.12. The best architectures, requirements, and designs
emerge from self-organizing teams.13. At regular intervals, the team reflects on how to
become more effective, then tunes and adjusts its behavior accordingly.
Adaptive (agile) vs Predictive (plan-driven) Agile home ground
Low criticality Senior developers Requirements change very often Small number of developers Culture that thrives on chaos
Plan-driven home ground High criticality Junior developers Requirements don't change too often Large number of developers Culture that demands order
Extreme programming Form of agile software development
Traditional software engineering practices taken to so-called "extreme" levels—leads to a development process that is more responsive to customer needs ("agile") than traditional methods, while creating software of better quality.
Values and/or principles Communication Simplicity Feedback Courage Respect
Activities Coding Testing Listening Designing
XP practices Fine scale feedback
Pair programming Planning Game Test driven development Whole team
Continuous process Continuous Integration Refactoring or Design Improvement Small Releases
Shared understanding Coding Standards Collective Code Ownership Simple Design System Metaphor
Programmer welfare Sustainable pace
Coming back to CI Continuous Integration 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. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly.
… taken from Martin Fowlers article on CI
Practices
Maintain a single source repository Keep everything needed for build in
CVS E.g. code, database schema, IDE
configuration, test scripts etc but not application server and jdk. Even no build artifacts!
Keep branches to minimum (in size and in lifetime)
Practices
Automate the build From compilation to deployment Configure the build:
Master build on server Developers build from IDE Build with test, without test or different
set of tests!
Processes Make your build self-testing
High degrees of automated tests suits to check larger code base
Though TDD not mandatory but its helpful Test case failed: build failed! XUnit tools like JUnit and/or end-to-end
testing tools like selenium Imperfect tests, run frequently, are much
better than perfect tests that are never written at all.
Processes
Everyone commits every day Every commit shall succeed the build Frequent commits: small work
packets for developer Mentoring and practice is the key
Processes Every commit should build the mainline
on an integration machine You shouldn’t go home until the mainline
build has passed with any commits you’ve added late in the day!
Don’t check in untested / broken code Don’t check in when build is broken The whole point of CI is to detect integration
errors as soon as possible Peers pressure within team ensures policies
are followed
Processes Keep the build fast
XP guideline: 10 mins build! Staged build (build pipeline)
Commit build Secondary build Performance build
If secondary build fails move the test case to commit build
Parallel builds
Processes
Test in a clone of production environment Every environmental difference
results in a risk: what happens under test wont happen in production
E.g. Same IP, port, machine, hardware, os etc
Virtualization can help
Processes
Make it easy for anyone to get the latest executable Its very hard to specify what you want
in advance and be correct; people find it much easier to see something that’s not quite right and say how it needs to be changed
Many executables in a day so not in CVS
Processes
Everyone can see what's happening CI is all about communication Build status indicators: lava lamps,
colored labels, hooters, mails Build history and build status reports
indicates the project “health” Matrices are helpful to guide project
management
Processes
Automate deployment Use deployment pipeline Automated rollback
Advantages Reduces risk
Integration is predictable now We know where we are, what works, what doesn't work,
how many outstanding bugs are there Makes dramatically easier to find and remove
bugs Bugs - these are the nasty things that destroy confidence
and mess up schedules and reputations. Bugs in deployed software make users angry with you. Bugs in work in progress get in your way, making it harder to get the rest of the software working correctly.
Broken windows syndrome Break Barriers between customer and
development Add more features rapidly, give rapid feedback
The road ahead Just give it a try Start with commit build Add some automated test Use deployment pipeline Speed up the build Integrate with anything and everything
available like project management tools, bug trackers, code analysis tools etc
Deployment pipeline
Image Courtesy: Paper on Deployment Pipeline by Dave Farley
Cruise control
Open source CI toolkit from ThoughtWorks Support for different plugins like
email, source control, builder, ant etc Support of web ui for build status Integrate with many code analysis
tools, scm tools, build tools, reporting tools etc
Cruise control
Image Courtesy: CC documentation on cc website
References http://martinfowler.com/articles/continuousIntegration.html http://en.wikipedia.org/wiki/Agile_software_development http://en.wikipedia.org/wiki/Extreme_Programming http://cruisecontrol.sourceforge.net/
Q&A
Thanks!