Equinox p2 Getting Started for Developers

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So you are interested in the provisioning code. Great! There are several levels of involvement ranging from calling the API to contributing provisioning code. This page should help you understand how to do all of those. If you are actually looking to get started as an end-user of the provisioning facilities then check out the getting started guide for users.

Contents

Getting the code

The p2 sources are being moved to Git (see [1]) – This information is partially outdated!

  1. Get the most recent 3.7 build available (http://download.eclipse.org/eclipse/downloads/)
  2. Create a CVS repository location for ":pserver:anonymous@dev.eclipse.org:/cvsroot/rt". Hint: Select the quoted text, open the CVS Repositories view, and select Paste Connection or hit Ctrl+V to add the connection
  3. Expand HEAD > org.eclipse.equinox > p2.
  4. Checkout "org.eclipse.equinox.p2.releng". Should you need to work on a maintenance stream (e.g. 3.6.x), you can find a branch of this project.
  5. Import the "projectSet.psf" project set by right clicking on the file in the Package Explorer and clicking Import Project Set... in the releng project you just checked out. If you are a committer, and able to make an extssh connection, you can use projectSet-extssh.psf

You will get a mess of projects added to you workspace and you are "good to go".

Understanding the code

While it would be extremely hard to capture essence of all the different code areas here, we can give you a few starting points and places to look.

  • The Equinox p2 Concepts document sets out much of the terminology for and relationships between the different elements of the Equinox provisioning system.
  • ProvisioningHelper in the console bundle. This is a helper class that has lots of useful methods and is useful as an example of how to do various operations. Note that this class is currently not API and is sadly misplaced to be widely useful (in the console bundle?!), but overall, it is very educational.
  • Also it worth nothing that the code you check out contains two kinds of bundles. First are the runtime bundles (you will deploy a subset of those when you want to use p2 as a provisioning system, e.g. engine, director, etc.), second are the bundles related to tooling (e.g. publisher, metadata.generator, repo tools, etc.).

Self hosting

  • Since 3.6 (Helios) PDE has introduced limited support for self-hosting p2. This means that on startup PDE will generate a profile from the set of bundles that you have selected. To enable this functionality, select the "Support software installation" option in the configuration tab of the launch configuration. Note though that this has some limitations and may not represent the reality of your deployed application to a 100%.
  • Another approach, useful when you want to work against an existing p2 profile, is to set the p2 data area of the launched workbench to point to the p2 directory of the profile that you want to debug. These arguments can be added to the launch configuration of your workbench. For example, if the eclipse install you wish to work with is in "c:/testBuild" then your launch config arguments look like this:
-Declipse.p2.data.area=C:/testBuild/eclipse/p2/
-Declipse.p2.profile=SDKProfile

It's not such a good idea to point the launch config at the host eclipse, since you could potentially trash your host profile while debugging new code.

My first run

Note that there are also a bunch of launch configurations that come in the various projects. We can't explain them all here but looking at the launch configs (and the code they run) is one interesting starting point. To get a feel for how things work the section below walks you through using a few of the launch configs to setup a working provisioning system.

  1. director app This allows you to run the director application, which is a headless way to install and uninstall using p2. http://help.eclipse.org/ganymede/index.jsp?topic=/org.eclipse.platform.doc.isv/guide/p2_director.html
  1. Publisher * This allows you to generate p2 metadata from various input