Convert Eclipse p2 tycho repositories to Maven Notes

From Issue #1, it would be nice to have JFace and SWTBot in this repository. However they have dependencies that must be resolved with something. A hacky bash script will work for now, but a more permanent solution is to use Eclipse's existing p2 system. Long term this might let us easily mirror other Eclipse projects

This page document's that attempt

##Notes

• p2/tycho is part of Eclipse's huge enterprise-y Equinox OSGi framework
• p2 is the type of repo?
• tycho is a maven plugin to generate bundle's and/or p2 repos
• SWT is actually a maven project! http://git.eclipse.org/c/platform/eclipse.platform.swt.git/tree/pom.xml

Useful links

• SWT sources: http://www.eclipse.org/swt/git.php
• Map of packages to RCP plugin id's: http://help.eclipse.org/juno/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fmisc%2Foverview-platform.html

Useful commands

• Mirror p2 repo locally https://wiki.eclipse.org/Equinox_p2_Repository_Mirroring , http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/guide/p2_mirror.html
  • ./eclipse -nosplash -verbose -application org.eclipse.equinox.p2.artifact.repository.mirrorApplication -source http://download.eclipse.org/technology/swtbot/snapshots/ -destination ../qp2-swtbot/
  • ./eclipse -nosplash -verbose -application org.eclipse.equinox.p2.artifact.repository.mirrorApplication -source http://download.eclipse.org/releases/mars/ -destination ../qp2-mars/

##Potential solutions

• eclipse:to-maven goal from https://maven.apache.org/plugins/maven-eclipse-plugin/to-maven-mojo.html

  Repackages all the bundles from a Eclipse installation/SDK folder into your local maven repository. Doesn't have a whole lot of configuration options

• bnd - http://bndtools.org/

  Its used for OSGi building from Maven, how does it get its dependencies? Are they stored in the user's m2 repo?

• p2-scripts project: https://github.com/briandealwis/p2-scripts

  Potentially useful p2 bash scripts

• p2 ant tasks: http://help.eclipse.org/juno/topic/org.eclipse.platform.doc.isv/guide/p2_repositorytasks.htm

  Another view of their API

• Write custom bash script to download, repackage, and generate pom's for all the dependencies and packages.

  • Pros
    • Can do this now without having to figure out how extract them from p2
    • Doesn't sound too mentally difficult
  • Cons
    • Time consuming to do for every dependency for every existing supported release
    • Time consuming to do for every new eclipse release, especially the dev-releases repository
    • Most likely will be fragile as future p2/tycho versions could change their internal format

• Write custom Java CLI app that calls the p2, tycho, and Maven API's directly

  • Pros
    • Gives 100% control of the whole process with a lot less magic
  • Cons
    • Takes even more time to write against the internal Java API
    • More complicated than a bash script
    • The internal API might change more in the future than the external CLI api

##Dead ends

• https://github.com/reficio/p2-maven-plugin

  N/A, used to depend on Eclipse RCP plugins from regular maven projects

• Eclipse's official Nexus Maven Repository: https://repo.eclipse.org/

  Only contains libraries for some projects (but not JFace, SWT, or SWTBot). Eg https://repo.eclipse.org/content/repositories/eclipse only has JDT and e4 JARs.