Introduction to project industrialization with Maven 2

Introduction to project industrialization with Maven 2
Introduction to project industrialization using Maven YaJUG 06/10/2009 Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Event   http://www.yajug.lu   October 06 2009 Best Practices and Tools for your build environments Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Speaker   Pierre-Antoine Grégoire   I.T.Architect at   Occasional committer in open source projects   Dislikes buzzwords (SOA, EDA…), likes to conceptualize and build architectures   Thinks having fun and working seriously (both at the same time) should be mandatory! Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Who are you?   Who in the audience is currently coding at work?   Who in the audience is managing the lucky coders?   Who is already using Maven 2+?   Who is planning on using it and came to have more information? Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Planning   Software development is engineering   A bit of history   Why Maven?   An introduction to Maven   Drawbacks of Maven   Best practices   Maven 3.x preview   Maven in a Software development suite Textual content under Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Software development is engineering   Since the early days of modern engineering, automation of build processes has been the key to:   Productivity improvements   Quality insurance   Failure-Proofing   Why would software development be any different? Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Software development is engineering   How do you really enable automation of build?   Build has to be reproducible   Build has to produce the final production artifact   Build has to be as easy to maintain as possible and well documented   Build has to contribute to the standardization effort Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
A bit of history   Software craftmens are lazy, so they are looking for efficiency (or the other way around… )   One command line to launch for a build, OK   Two command lines to launch for a build, BAD enough   More… forget it…   Disclaimer: I’m one of these lazy craftmen… Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
A bit of history   A simple script (.sh, .bat) is already a possible solution   More advanced command-line tools have been available for a long time   make created in 1977 at Bells Labs by Stuart Feldman   Still very much used nowadays   Apache Ant created by James Duncan Davidson   Was at first a platform-independent build system for Tomcat because Sun’s build system for Servlet RI (From which Tomcat was derived) was specific to Solaris.   Released separately in 2000 Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
A bit of history   Two main categories in current tools   Scripting tools   Ant and derived (XML)   Rake (Ruby based)   Gradle (Groovy based)   … many others   Artifact oriented tools   Maven   Debian Package Creation Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
A bit of history   Maven 1.x is now a 10 years old project, mostly motionless since 2007 (no insult intended to people still using it or committing to it)   Maven 2.x is the de facto standard for Java and Java EE build   Most open source projects are switching to Maven for their build system   It’s now five years old Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Why Maven?   Nowadays, build tools are not really used by developers directly.   IDEs are increasing their functionalities scope,   Compilation is almost always done on the fly   Package and server startup is monitored by rich Uis   Step-by-step debugging is a killer feature   Build tools like Maven 2 are used to build the package you will put into production! This should never be done by an IDE, nor by hand! Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Why Maven?   If you are not already using it:   Now is the best moment to start being aware   Maven is mature   Maven is getting better and better   Maven can be used online, offline, and in enterprise environment   If you are already using it:   Hang on! The best is yet to come!   Focus on necessary things and don’t get frustrated by petty details Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Maven 2 is a tool with multiple facets:   a BUILD tool   a DEPENDENCY MANAGEMENT tool   a DOCUMENTATION tool Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven Project Object Model pom.xml mvn Generated artifacts (jar, war, ear…), Documentation, statistics (test results, quality metrics, javadoc, web site)… Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   A project can easily be cut into modules thanks to Maven 2   By simply declaring project metadata and optionally configuring a few plug-ins, you can:   Build your project (compile, generate sources…)   Launch tests and gather results (Junit, TestNG, Selenium…etc)   Package (Jar, War, Ejb, War…etc)   Document and generate reports Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Project Object Model (POM)   Basic project information   groupId, artifactId, version…   Inheritance, or Aggregation through sub-modules (we’ll explain the difference later on)   Build section   Project layout (sources and resources folders… etc)   Build plugins configuration   Reporting section   Reports configuration   Some other advanced environment settings Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   A plug-in is made of a MOJO (Maven POJO) which is simply a java class with Maven-specific metadata.   A plug-in can define goals and reports   Goals can be called directly:   mvn plugin:goal   Goals can be bound to one or multiple phases   Reports are used during site generation   mvn site Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven Phase compile mojo mojo test mojo package Plug-ins install mojo mojo deploy Mojos define Goals (fine Lifecycle grained tasks) Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   When you invoke a phase, Maven 2 will go through all the phases until the one specified, executing the bound goals:   mvn package compile compiler:compile test surefire:test package jar:jar Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   There are many more phases than in previous examples in the default lifecycle   By default, all the basic necessary plug-ins for the build phase are already bound to phases   It is easy to have information about plugins:   mvn help:describe   So….. what’s left to do, and what’s all the fuss about the complexity of Maven 2? Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Dependencies: A blessing and a curse   Blessing:   almost all java build tools nowadays leverage the Maven 2 repositories (cf. Ivy, Ant, Gradle…etc)   easier to find/discover/use java libraries   Curse:   Transitive dependencies can rapidly trigger a dependency hell!   Curse: Harder to stabilize builds Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   What really made Maven different from other builds systems in the first place?   REPOSITORIES!!!   Before Maven, it was really hard to find java libraries, and harder to ensure a coherent use of these libraries (I’m saying hard, not impossible…)   Nowadays, it’s still very hard to find some jars with a decent/coherent versioning (discretely winking in the general direction of Sun participants...), let alone to find their sources or javadocs Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven Local repository Corporate repository/ proxy Public repository Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Local repository: Local repository   Local cache for artifacts Corporate repository/ proxy   Local private sandbox Public repository   It should be possible to erase it regularly   Very useful for offline builds   By default in user home’s .m2/ folder   Can be moved to another place through Maven 2 runtime’ settings.xml file   $MAVEN_HOME/conf/settings.xml Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Corporate repository/proxy Local repository   Very useful tool Corporate repository/ proxy   The first necessary step towards a Public repository corporate use of maven   Can be as simple as a corporate http server exposing a repository   Even better: install a repository management tool   Can proxy external repositories   Can filter unwanted artifacts   Build even without internet access! (well… at least for the repository management tool) Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Public repositories Local repository   Good for dependencies’ harvesting Corporate repository/ proxy   Should be proxied in corporate Public repository environments… or even for your personal use!   A lot of mis-configured dependencies   A lot of alpha/beta Maven 2 plugins   Be cautious when adding public repositories to a build process! Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven Other key features of Maven:   POM Inheritance/Aggregation   Archetypes   Launching Tests   … many more… Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   POM Inheritance vs. POM Aggregation   POM Inheritance:   a POM and all its parent POMs will be flattened at runtime   In the end only one effective POM in memory   This is mostly used to share common configuration   POM Aggregation:   declare modules in a given project   If a command is issued against a project, it will be also issued against all its modules   This is mostly used to organize builds and gather projects that should be built simultaneously Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven   Project Archetypes   You can build template projects and make them available as artifacts in the repositories   Allows to share best practices without neither inheritance nor aggregation   mvn archetype:create-from-project   mvn archetype:generate   Many Archetypes already configured in the default catalog   You can easily build a custom or corporate catalog mvn archetype:generate –DarchetypeCatalog=http://www.corporate.com/ archetypes.xml Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
An introduction to Maven Launching Tests   Maven 2 allows to launch various types of tests:   Unit tests: Junit 3.x or 4.x, TestNG, …   UI Tests: Selenium, Canoo Webtest   Functional tests: Fitnesse, Greenpepper   WebServices tests: SOAPUi   And many more… Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Drawbacks of Maven   If you don’t embrace the standardization brought by Maven 2, you’ll soon feel limited by Maven 2   Additionally, standardization can be quite expensive! Measure the implied cost by testing on 2 subsequent projects (one to absorb the POC effect, and one for measure)   By default Maven 2 has its own folder structure normalization, unknown to IDEs (though this is not completely true anymore)   Last but not least: Maven 2 error reporting is SO BAAAAD! Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Worst practices You want more drawbacks? GET MORE OF THEM!   Use maven-antrun-plugin a lot!   So coool, this way you can use Maven and not Ant!   Build very intricated projects with modules having modules themselves, and lots of inheritances all around!   Niiice! This allows you to spend more time with your favorite tool: Maven 2 in order to find out where your damn properties/dependencies are defined!   Replace your IDE with Maven and try to add all of your IDE’s functionalities as Maven plugins!!!!!   You got my point ;) Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Best practices They will allow you to overcome Maven 2’s drawbacks   Embrace the standardization brought by Maven 2, don’t fight it   Use POM Inheritance and <dependencyManagement> (with import scope), <pluginManagement> to tame the transitive dependencies. (don’t mistake these for <dependencies>, <plugins>…)   Use a Repository Manager:   Sonatype Nexus: http://nexus.sonatype.org   Jfrog Artifactory: http://artifactory.jfrog.org   … Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Best practices   Don’t use Maven’s integrated reporting anymore   It was meant for Apache project’s web sites static documentation   The amount of time spent in order to build them is not worth it in enterprise environment   Keep your build as simple as possible   Generate test statistics data and other metrics data in order to exploit them in Software quality tools:   Sonar: http://sonar.codehaus.org   Squale: http://www.squale.org   … Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Best practices   If you provide a standard environment, try to make Maven plugins have a match in the IDE   If Maven 2 launches Checkstyle, provide the Checkstyle Eclipse plugin to your projects.   Launch your builds regularly and possibly in a neutral zone (not on the developer’s desktop!) in order to ensure “rule number one” is respected: Build must be reproducible.   Use the “dependency” and “versions” plugins to handle dependencies and diagnose dependencies mismatches or errors Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Best practices   Documentation and information:   Site http://maven.apache.org   Plugins   http://maven.apache.org/plugins   http://mojo.codehaus.org/   http://code.google.com/   And many others…   Project Wiki http://docs.codehaus.org/display/MAVEN/   Users’ Wiki http://docs.codehaus.org/display/MAVENUSER Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Best practices   Books   Free electronic editions:   Definitive Guide: http://www.sonatype.com/books   Better Builds with Maven: http://www.maestrodev.com/better-build-maven   Upcoming book by Arnaud Héritier and Nicolas De Loof http://www.pearson.fr/livre/?GCOI=27440100730370 Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Maven 3.x Preview   DISCLAIMER!!!   Everything mentioned here could end up being COMPLETELY FALSE!!! (though project is now well advanced) Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Maven 3.x Preview   New release planned for this autumn/winter   Lots of refactorings of the insides of Maven 2   Not immediately obvious (in a way this is better than the complete product change between Maven 1 and 2)   Will allow to tackle upcoming challenges and regular issues of Maven 2 in a more elegant manner   Simplifies plug-in development   Efficient embedder   Maven 2 has lots of singletons and such and is therefore improper for use in multithreaded environments (CIM, IDE) Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Maven 3.x Preview   Backward compatibility   Loads of Integration testing is done to ensure backwards compatibility   Stricter validation of the POM   Configured plugins should have their versions specified (a warning appears otherwise)   Site/reporting is now completely extracted from the Maven core   Currently the Site plugin doesn’t work with Maven 3, yet should until the final release (though reports still work)   Recommended to switch to the use of external quality monitoring tools Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Maven 3.x Preview   If you plan to migrate or want to evaluate: http://cwiki.apache.org/confluence/display/MAVEN/ Maven+3.x+Compatibility+Notes   Presentation by Jason van Zyl (Sonatype) http://www.scribd.com/doc/14458957/Jasons-Maven-3- Presentation   My first impressions:   Maven 3 looks awesome!   Embedder is a killer feature   The IDE can literally listen for the Build process, and be part of it, not just launch it. Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Maven 3.x Preview   What will be new to users:   Versionless parent elements   Better version delegation   Better error and integrity reporting   XML Pom format using attributes instead of elements   Scripted POM Formats (pom.{rb|groovy|py})   What will be new to plugin developers:   Plugin extension points   Annotations instead of old javadoc tags   Lifecycle extension points   Queryable lifecycle Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
Maven in a Software development suite   Maven is now very well integrated in IDEs   NetBeans 6.5+ now has very good support for Maven 2   Eclipse 3.x has very good support also, with preview of Maven 3.x embedder (blazingly fast!)   IntelliJ IDEA seems to have excellent support also (though this is why you pay for it isn’t it?)   Maven works very well with Quality monitoring tools   Maven 3 will most likely increase the embedding of Maven and its use for other JVM Languages and possibly for other platforms Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0
References and Thanks   Many thanks to Arnaud Héritier   He allowed me to be inspired by some of its recent slides presented to the French Ch’ti JUG http://blog.aheritier.net   He also was kind enough to review this presentation ;)   Many thanks to Jason van Zyl for its Maven 3 presentation I was heavily inspired by http://www.sonatype.com/people/author/jason Copyright © Pierre-Antoine Grégoire License Creative Commons 2.0

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