LyonJUG - Maven 3.x, will it live up to its promises?

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A tour of all changes done in Maven 3.0 and planned in a near future to solve common issues reported by the community about Maven 2.x.

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LyonJUG - Maven 3.x, will it live up to its promises?

  1. 1. 1 Apache Maven 3.x Will it live up to its promises? By Arnaud Héritier
  2. 2. 2 About me •  Committer since 2004 and member of the PMC •  Coauthor of « Apache Maven » published by Pearson (in French) •  Software Factory Manager eXo platform » In charge of tools and methods •  Contact me : » http://aheritier.net » Twitter : @aheritier » Skype : aheritier
  3. 3. 3 Definition •  Apache Maven is a software project management and comprehension tool. •  Based on the concept of a project object model (POM) » Maven can manage a project's build, binaries, reporting and documentation from a central piece of information. •  Apache Maven is standards/conventions driven » How many of you are doing JEE and related developments ?
  4. 4. 4 History •  Initiated in 2001 by Jason Van Zyl in Alexandria, an Apache Jakarta project, •  Moved to Turbine few months after, •  Became a Top Level Project in 2003. •  Maven 2.0 released in September 2005 •  Maven 3.0 released in October 2010 » 3.0.1 soon (RC1 staged)
  5. 5. 5 Choose your way of thinking Conventions approach Scripting approach
  6. 6. 6 Competitors •  Ant + Ivy, Easy Ant, Gant, Gradle, Buildr… •  Script oriented » You can do what you want ! •  Reuse many of Maven conventions (directories layout, …) and services (repositories) but without enforcing them •  The risk for them : Not being able to evolve due to the too high level of customization proposed to the user. » We tried on Maven 1 and it died because of that. It was impossible to create a set of tests to cover all usages. » It’s like providing a framework without public API L
  7. 7. 7 With scripts oriented builds You can have (if you have good skills) But often you have (moreover after years …)
  8. 8. 8 With Maven We dream to deliver (Maven 3.x) But yesterday we too often had (Maven 2.x)
  9. 9. 9 BACKWARD COMPATIBILITY Apache Maven 3.x
  10. 10. 10 Backward compatibility - Criticisms •  Migration from Maven 1 to Maven 2 was impossible. Everything had to be re-done. •  Updates between 2.x versions and also between 2.0.x weren’t often without side effects.
  11. 11. 11 Backward compatibility •  Near to 700 integration tests •  Tested for months on a large set of OSS projects •  7 alphas + 3 betas versions •  It’s a revolution under the hood but an evolution for end users
  12. 12. 12 Maven 3.0.x ITs 674
  13. 13. 13 PERFORMANCES Apache Maven 3.x
  14. 14. 14 Performances - Criticisms •  Maven is slow •  It spends its time to download the world •  Whereas everybody has multicore CPUs, it doesn’t allow to process modules builds in parallel
  15. 15. 15 Performances •  A set of benchmark tools was developed to measure Maven performances (IO, CPU, Memory, Network …) •  Startup and execution times are reduced » Java 5 optimizations » Code cleanup and improvements •  Reduced Memory footprint •  Artifacts Resolution Caching » .lastUpdated files in your local repo » Enforce checks with –U option
  16. 16. 16 Performances – Parallel builds •  Parallel builds » An execution plan is predefined at startup to define which modules could be built in // » Requires to have up to date plugins to avoid dead locks and some others issues » Launch a build with 2 threads •  mvn –T 2 install » Launch a build with 2 threads per CPU core •  mvn –T 2C install
  17. 17. 17 Performances – mvnsh •  Performances optimizations » Intelligent cache system (artifacts resolution, project descriptors …) » No need to restart a JVM for each build •  Cross platform « unix like » shell » Alias, environment settings … » Color highlighting
  18. 18. 18 Performances – mvnsh •  All in one » Includes Maven 3.x » Allows to have color highlighting with “standard” Maven 3.x •  Developed and freely distributed by Sonatype
  19. 19. 19 Performances – mvnsh
  20. 20. 20 EXTENSIBILITY Apache Maven 3.x
  21. 21. 21 Extensibility - Criticisms •  It is difficult and time consuming to extend maven (write plugins) » Many unknown technologies like Plexus for IOC •  It is difficult/impossible to reuse maven plugins » Its impossible to extend plugins/mojo and lifecycles
  22. 22. 22 Extensibility •  New APIs to improve abstraction of underneath implementation » Aether : to manage artifacts and repositories •  Plugin classloader partitioning •  Embeddable •  IOC replaced by Guice » For now (3.0) a wrapper is hiding the change » You don’t yet use Guice directly (from plugins for example)
  23. 23. 23 ROBUSNESS Apache Maven 3.x
  24. 24. 24 Robusness - Criticisms •  Builds aren’t predictable •  Errors are difficult to diagnose
  25. 25. 25 Robusness - Validations •  Many more validations in POMs (warnings or errors) » Missing plugins versions » Duplicated dependencies in a POM » Incoherent inheritance (wrong relative path or parent not in the upper directory) •  Improved error messages with links to wiki pages for more detailed information
  26. 26. 26 Robusness – Artifacts management •  Parent POMs prefer to resolve from repositories » Version less parent will be available in a future maven 3.x release by using the relativePath element •  Profiles usage consolidation » No more profiles.xml (incompatible with future polyglot feature)
  27. 27. 27 Robusness – Artifacts management •  No more support for legacy repository layout for Maven 1.0 •  SNAPSHOTs are always deployed with timestamps
  28. 28. 28 Robusness – Plugins management •  Plugin version is by default RELEASE and no more SNAPSHOT » Affects command-line invocation •  Plugins cannot use versions LATEST or RELEASE » Affects command-line invocation and POM •  Plugins are resolved only from <pluginRepository> entries
  29. 29. 29 Robusness – Site plugin •  Site plugin is now completely extracted from Maven core » It has its own lifecycle » reporting section in POM becomes useless (moved in plugin configuration)
  30. 30. 30 POM Apache Maven 3.x
  31. 31. 31 Criticisms •  XML, we don’t like it •  POM is too verbose •  POM v4 didn’t evolve last 5 years » When will you add new common attributes to ease plugins configuration (encoding …) » New feature like global exclusions
  32. 32. 32 POM •  No change in POM syntax for Maven 3.0 •  Changes will occur in 3.x versions » New model with a new version » Only new things » Generation / deployment of 4.0.0 current POM to keep backward compatibility with old maven versions •  Mixins to allow to import POM fragments
  33. 33. 33 POM - Polyglot •  Developed and freely distributed by Sonatype •  Extended version of Maven 3.0 using its new embedding and extensibility capabilities •  Allow translation (read/write) from/to various syntaxes » Yaml » Scala » Groovy •  Allow macros and freeform scripting
  34. 34. 34 QUESTIONS ? Apache Maven
  35. 35. 35 Licence et copyrights •  Photos and logos belong to their respective authors/owners •  Various ideas are coming from the excellent presentation done by Matthew McCullough : » http://www.slideshare.net/matthewmccullough/ maven-30-at-oredev
  36. 36. 36 Licence et copyrights •  Content under Creative Commons 3.0 » Attribution — You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). » Noncommercial — You may not use this work for commercial purposes. » Share Alike — If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one. •  http://creativecommons.org/licenses/by-nc-sa/3.0/us/
  37. 37. TO GO FURTHER … Apache Maven
  38. 38. 38 COMMUNITY Apache Maven
  39. 39. 39 Users Mailing List •  Blue : » Number of subscribers •  Red : » Number of messages per day •  users@maven.apache.or g » Traffic statistics cover a total of 1697 days. » Current subscribers: 1861 » Current digest subscribers:47 » Total posts (1697 days): 80633 » Mean posts per day: 47.52 •  http://pulse.apache.org/
  40. 40. 40 Apache Maven Web Site
  41. 41. 41 Dowloads Per month downloads http://people.apache.org/~vgritsenko/stats/ projects/maven.html
  42. 42. 42 The team •  60 committers, •  More than 30 active in 2009, •  Several organizations like Sonatype, deliver resources and professional support, •  A community less isolated : more interactions with Eclipse, Jetty,
  43. 43. 43 Commit Statistics
  44. 44. 44 DOCUMENTATIONS Apache Maven
  45. 45. 45 Some links •  The main web site : » http://maven.apache.org •  Project’s team wiki : » http://docs.codehaus.org/display/MAVEN •  Project’s users wiki : » http://docs.codehaus.org/display/MAVENUSER
  46. 46. 46 Books •  Nicolas De loof Arnaud Héritier » Published by Pearson » Collection Référence » Based on our own experiences with Maven. » From beginners to experts. » In French only
  47. 47. 47 Books •  Sonatype / O’Reilly : » The Definitive Guide » http:// www.sonatype.com/ books » Free download » Available in several languages
  48. 48. 48 Books •  Exist Global » Better builds with Maven » http:// www.maestrodev.com /better-build-maven » Free download
  49. 49. 49 SUPPORT Apache Maven
  50. 50. 50 Support •  Mailing lists » http://maven.apache.org/mail-lists.html •  IRC » irc.codehaus.org - #maven •  Forums » http://www.developpez.net/ forum maven » In French •  Dedicated support » Sonatype and many others companies

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