This presentation goes over the things you should know not do with p2 and proposes a bet

1. p2, your savior or your Achilles heel? Everything an Eclipse team needs to know about p2! R. Ian Bull Pascal Rapicault

2. Alternate Titles 10 reasons we closed your p2 bugs as INVALID? 10 ways to get booted from the p2 mailing list! 10 excuses why we didn’t buy you a beer  p2, 10 common pitfalls and how to avoid them. 3/21/2011 2

3. #1Move / remove files on disk Leading cause of p2 failures: developers tampering with plugins/ folder If you no longer need a pluginDO NOT REMOVE IT BY HAND Do not move, unzip or change a plug-in in your plugins/ directory 3/21/2011 3

4. Instead:Let p2 manage your install Other plug-ins may depend on it If a plug-in is no longer needed, p2 will remove it Run the Garbage Collector manually if you want # ./eclipse –application org.eclipse.equinox.p2.garbagecollector.application 3/21/2011 4

5. #2 Unzip your plug-ins over Eclipse Do you provide a zip file for your plugins? Do you instruct your users to unzip over eclipse We don’t like you! (And we will sabotage your wiki page  ) 3/21/2011 5

6. Instead:Provide a repository Repositories can be zipped and downloaded! Users can simply point to the compressed repository to properly install your plug-in Avoid the use of drop-ins too 3/21/2011 6

7. #3Replace published content Never publish different content with the same version number! Do not make a change and use the same version number Do not build plug-ins as Foo v1.0.0.HEAD You’ll never know what your user runs. 3/21/2011 7

8. Remember: Version / ID pairs are immutable If the Version / ID has not changed, the content hasn’t changed! Always publish new metadata and artifacts for each code change Use .qualifiers for all bundles / plug-ins and features If you can’t rebuild everything, provide patches to deliver surgical updates 3/21/2011 8

9. Reuse:Tips and Tricks Context repositories Qualifier replacement / bundle reuse forceContextQualifier: Replaces the qualifier of all your bundles (use build timestamp) Feature patches: http://help.eclipse.org/helios/index.jsp?topic=/org.eclipse.pde.doc.user/guide/tools/project_wizards/new_feature_patch.htm (or google: eclipse p2 feature patch)  3/21/2011 9 build.properties:repoBaseLocation=${buildDirectory}/inputRepositoriestransformedRepoLocation=${buildDirectory}/transformedRepo

10. #4 Alter a released repository “Release” repositories are serious stuffs! People will refer to them from their repo to avoid duplicating your content People will refer to them from their build Removing content from a “release” repo is a felony! 3/21/2011 10

11. Instead:Be mindful of your users / repos Preserve content at the same URL If you put out bad bytes, publish a new version. Don’t remove the old one ! Append new version to existing repo. Disk is cheap, users not patient (and they’ll blame p2). For this, use p2 composite repositories. Define clear retention policies For example, the policies for the SDKhttp://wiki.eclipse.org/Eclipse_Project_Update_Sites 3/21/2011 11

12. #5Don’t categorize things p2 only shows what’s been categorized Repository designers are responsible for designing their categories Classic consumer / producer problem 3/21/2011 12

13. Remember:Category tricks Use categories ! The category publisher is here to help Use composite repositories where one of the repo carry the categories Use meaningful name, and use the description. The feature name is shorter than a tweet. 3/21/2011 13

14. #6Ignore your version ranges Specify a strict dependency on 3.6.1 and wonder why your users can’t install on 3.6.2? Most illegible p2 error messages are a result of poorly set version ranges 3/21/2011 14

15. Instead:Consider your version ranges Version your packages, bundles and features Use version ranges for dependencies: Up-to by not including [3.6.0, 3.7.0) Unbounded lower [0.0.0, 3.7.0) Unbounded higher 2.0 Strict Versions [3.6.1, 3.6.1] You need to know what the producer does. 3/21/2011 15

16. #7Don’t USE API If you find yourself reaching into internals, ask yourself why? If you manually write to the bundles.info file, ask yourself why? If you edit content.xml / artifacts.xml by hand, ask yourself why? Two problems when you don’t use API: We could break you You could break you 3/21/2011 16

17. Instead:Be mindful of what you use Look for provisional API (if real API doesn’t exist) Ask on the p2-mailing list 3/21/2011 17

18. #8Use the Metadata generator If you are using the Metadata generator… sorry  (org.eclipse.equinox.p2.metadata.generator) Deprecated two years ago Removed for Indigo 3/21/2011 18

19. Instead:Use the Publisher Publisher Applications & Ant Tasks Publish from an Update Site Publish from Features / Bundles Publish from a Product Publish categories # ./eclipse -application org.eclipse.equinox.p2.publisher.UpdateSitePublisher -metadataRepositoryfile:///repo -artifactRepository file:///repo-source http://foo/site.xml-compress-publishArtifacts 3/21/2011 19

20. #9Use legacy update sites Legacy update sites don’t include complete metadata Features are downloaded before any dependency resolution can occur Big lag at install time. We will blame you for all p2’s performance problems  3/21/2011 20

21. Instead:Use a real build tool PDE Build, Tycho and derivatives (Athena, Buckminster, etc.) all provide facilities to build p2 repositories. If you can’t change your build technology, at lease use the Update Site Publisher. 3/21/2011 21

22. #10Spell it P2  I don’t call your project Mylin, έMF, or BERT 3/21/2011 22

23. Remember:The project is: p2 3/21/2011 23

24. Useful links http://wiki.eclipse.org/Equinox_p2 http://wiki.eclipse.org/Equinox/p2/Getting_Started http://wiki.eclipse.org/Equinox/p2/Publisher http://aniefer.blogspot.com/2008/06/example-headless-build-for-rcp-product.html 3/21/2011 24