Continuous Integration Peter Rautek Institute of Computer Graphics and Algorithms Vienna University of Technology

History Daily Build and Smoke Test [McConnell 1996] Daily (automated) build Test Present results Motivation Quality Pinpointing problem Social aspect Example - Windows NT  5.6 million lines of code 40000 source files 19 hours builds (on several machines) Daily! -> otherwise e.g. weekly -> it gets hard to fix Peter Rautek

History Benefit(s) Disadvantage(s) Continuous Integration [Kent1999][Fowler2000] Continuous quality control Small pieces of effort applied frequently Opposite of quality control after development Benefit(s) Early detection of bugs Disadvantage(s) Higher costs Peter Rautek

Best Practices Source code repository Automated builds Automated testing Everyone commits every day Every commit (to trunk) is built Keep build fast Build in clone of production environment Transparancy of build reports Nightly builds available (to everyone) Automated deployment Peter Rautek

Small independent components for very specific tasks Implementation Small independent components for very specific tasks Testing Documentation Building Deployment etc. Server that coordinates the tasks Custom scripts Automated build server software Peter Rautek

Test driven development Unit Testing Automated Testing Test driven development Unit Testing Write code plus tests Tests specify expected behaviour of functions, classes, modules, etc. preconditions and expected result Execute tests frequently (at least for each checkin) Early detect changes that break expected behaviour Peter Rautek

Library that handles test cases Test case inherits a TestClass Unit Testing Library that handles test cases Test case inherits a TestClass Runs tests on target classes Java: Junit tests Others ~20 C++: CppUnit: port of Junit Google C++ Testing Framework Others ~40 Peter Rautek

CppUnit Example Peter Rautek

Documentation Generation Parses source code Special comment blocks Principles Keep documentation close to code  Easy to maintain Expose project structure  Good overview Link documentation to source code  Exploration tool Peter Rautek

Documentation Generation Tools Peter Rautek

Documentation Generation Cross plattform ~20 C++ ~10 Free ~5 Do not completely suck ~1  For Java ~2  Doxygen, Javadoc Peter Rautek

Example Input /**  * \class [classname]  *  * \brief [brief description]  * \details [detailed description]  *  */ /**  * \brief [brief description]  *  * [detailed description]  *  * \param[in] [name of input parameter] [its description]  * \param[out] [name of output parameter] [its description]  * \return [information about return value]  * \sa [see also section]  * \note [any note about the function you might have]  * \warning [any warning if necessary]  */ Peter Rautek

Example Output ... Peter Rautek

Documentation Best Practice Do document Interfaces of modules Public functions APIs Public Classes (concepts) Don‘t document Private functions and internals Obvious stuff e.g., ./** This method returns the value **/ public void getValue() { return value; } Peter Rautek

Automated Builds Rules: code and dependency organization Framework: extendable by plugins Plugins: compile source code, build javadoc, package classes, deploy files, create reports, run unit tests, ... Project Object Model (POM) XML file with meta-information Best known for dependency management e.g., project depends on jUnit version 3.8.1 Does a lot of other things Peter Rautek

Project Object Model Peter Rautek

Very powerful command line tool IDE integration (e.g., eclipse plugin) Maven Summary Very powerful command line tool IDE integration (e.g., eclipse plugin) Java world (de facto standard?) C++ alternatives ? Native ARchive (NAR) plugin for maven (never tried) (never tried) Peter Rautek

Automated Build Server (Hudson) Continous integration server for Java Open source (MIT-license) Powerful web interface Peter Rautek

and more - see http://hudson-ci.org Hudson Features Build summaries Javadoc Test summaries Junit test details Email notifications Rss feeds and more - see http://hudson-ci.org xUnit plugin for C++ projects (never tried) Peter Rautek

Continuous Integration is best practice in software development Summary Continuous Integration is best practice in software development Development cycles are Quick Tested Transparent Tools Commercial Free Peter Rautek

References [McConnell 1996] Steve McConnell, Daily Build and Smoke Test, Best Practices, IEEE Software, Vol. 13, No. 4, July 1996 [Kent1999]  Beck Kent , Extreme Programming Explained. ISBN 0-201-61641-6, 1999 [Fowler2000] Martin Fowler, Continuous Integration, 2000,  http://martinfowler.com/articles/continuousIntegration.html [Schatten 2010] Alexander Schatten, Stefan Biffl, Markus Demolsky, Erik Gostischa-Franta, Thomas Östreicher, Dietmar Winkler, Best Practice Software-Engineering, Eine praxiserprobte Zusammenstellung von komponentenorientierten Konzepten, Methoden und Werkzeugen, Springer, 2010 Peter Rautek