Understanding and extending p2 for fun and profit

1© 2009 IBM Corp. and EclipseSource; All right reserved. Made available under Creative Commons Att. Nc Nd 2.5 license

Using p2 for fun and profit

Pascal Rapicault*

Ian Bull**

Andrew Niefer*

Jeff McAffer**

* IBM Rational** EclipseSource

© 2009 IBM Corp. and EclipseSource; All right reserved. Made available under Creative Commons Att. Nc Nd 2.5 license 2

Engineers Users

TestAutomated Builds

Test

source code

open source

licensed software

in-house built

applications

tools

runtimes

Provision what – where


• Packaged applications – source code

• Strict policy control – full flexibility

• Approved repositories – any repository

• Fixed configuration – dynamic configuration

• Fully automatic – user driven – (headless)

• Update to latest – update to policy controlled (downgrade)

Wide range of requirements


• An extensible provisioning platform

• Install and update technology in the SDK since 3.4– New UI, simplified workflow– Manage Eclipse, RCP and more

• exe, ini, bundles, registry keys, native code, …– Shared bundles across Eclipse-based products

• A provisioning solution for OSGi™ systems– Managing non-running instance– Start level, framework extension– Fine-grained dependency management

p2 is about installing!


• Eclipse proves the power of componentization

• Componentization naturally spreads

• More components → more management

• Management is hard

• It’s all about the Contract– Defining– Instantiating– Executing– Maintaining

Trends in Eclipse


How does p2 help?

• Manages the contract– Dependencies– Code– Settings– Integrations– Non-Eclipse parts

• Extensible

• GUI and Headless

• One consistent model


From Install to Service

• Installing and Updating are the same operations

• Installed shape same as zip shape– Flexibility in delivery

• Programmatic API for all operations

p2 offers a continuum from initial installation to serviceability


p2 in wild

• Installer for products (EPP Wizard, WindRiver, Motorola, IBM Rational, etc.)

• Server managed deployment solution and distros (Genuitec, EclipseSource)

• Remote management of device (EclipseSource)

• Dynamic builder – Buckminster (Cloudsmith)

• Provisioning of server side (EclipseSource)

• Cloud provisioning (EclipseSource)


Outline

p2 by example• Integrating p2 in a feature based RCP application• p2 concepts and architecture• Layout of our application on disk and additional p2 concepts• Creating and delivering an update• Creating and delivering an extension

• Automated build and repo management• Repo management• Metadata publication (source and product)• Categorizing content

Deeper in p2• Additional p2 constructs• From plug-ins and feaures to metadata• Plug-ins map• Reusing and tweaking the UI• Advanced concepts


p2 by exampleIntegrating p2 in a feature based RCP applicationp2 concepts and architectureLayout of our application on disk and additional p2 conceptsCreating and delivering an updateCreating and delivering an extension

Build and repo management

Deeper in p2


What is RCP?

• Rich Client Platform

• The minimal set of plug-ins needed to build a Rich Client Application

• Clients are free to use other plug-ins– Help– p2– GEF / Draw2D– Birt– …

Integrate p2 in an RCP Application• Publish the application to a repository• Install the application using p2• Update an existing install

• Add new functionality to the RCP application


What is a Product?

• An application-specific branding on top of a configuration of Eclipse plug-ins– Application icon– Splash screen– Help -> About information– Platform specific launcher




In the following example we are using a feature based product. However plug-in based product is supported Create a Bundle for your mail application

Every bundle needs a name and version with a qualifier

Let's call ours: org.example.mail

Creating a feature based product




Every bundle needs a name and version with a qualifier

Of course we want a Rich Client Application



PDE contains all sorts of examples, templates and documentation



Features have a name and version too

Let's create a Feature

Creating a feature for our plug-in


In order to keep things separated in the application, we create a feature that contains the p2 plug-ins we need.

For this example, it does not include the support for legacy sites nor drop-ins.

A feature for the p2 parts


Let's create a Product

Let's base ourproduct off features

On the dependencies tab we add the features that constitute the product

Creating the product file


Launching the product (from within eclipse)


In self-hosting mode, the application being launched is not p2-enabled, as such the p2 dialogs can not be brought up. We can only update if we have a profile.This problem will unlikely be addressed in 3.5.

The running product


Publishing the application to a repository


The result of the export

The export produced the application in a runnable form and also repositories. The application in a runnable form is *not* p2-enabled and will fail to open the p2 dialogs. This should be fixed for 3.5. Notice the file extensions on the artifacts and content file! What's in these JAR files? p2 repositories.




Deeper in p2


One construct to rule them all

Decouple decision making from the actual content

Everything is an IUEverything is installable

It is also referred to as “metadata”

IU(id, ver)


Anatomy of an IU

Provided

CapabilitiesRequired

Capabilities

Properties

Artifact reference

Actions

IU(id, ver)

Class: IInstallableUnit


Anatomy of an IU, more

• Update description– This allows to control of which IU and IU is an update of

• Applicability filter– This allows for an IU to express when it is only applicable to a

particular environment.


Anatomy of an IU, requirements / capabilities

• Capabilities and requirements are the mechanism by which an IU express what it provides and what needs.

• A capability is composed of a:– Namespace (string), name (string) and version

• A requirement is composed of a:– Namespace, name and version range

• Namespace, name and version are open ended.

• The requirements and capabilities expressed by IUs can be arbitrary and don’t have to all be in the same namespace.– Resources – RPMs, .exes, docs, …– Virtual – if you can define a capability, I can depend on it


Separation of concerns

• Installable Unit– Exists independently of the repository

• Metadata Repository– Store only Installable Units

• Artifact Repository– Store only Artifacts

Metadata Artifacts


Artifacts

• Bytes/content to be installed

• Any form– JARs (e.g., bundles, features, …)– Binary executables– RPM, MSI, …

• Defined, maintained, loaded and used separately from the metadata


Repositories

p2 does not force a serialization format for repositories

• Defined as an interface, IRepository

• All repositories have– Identity– Version– Description

• Repos can be queried– Allows for delayed loading– Captures standard questions


Metadata Repository

• Defined as an interface, IMetadataRepository

• Add/remove installable units

• Add references to other repos

• Created by factories

• Looked up in an IMetadataRepositoryManager service


Built-in metadata repositories

• URL and Local based– Simple XML format on disk (content.jar / content.xml)– Write (re)writes the entire structure

• Update site repo– site.xml and features are auto-published into local repo– Bundle IUs published as partial IUs and filled in on demand


Artifact Repository

• Defined as an interface, IArtifactRepository

• Add/remove descriptors

• Test content

• Access artifacts by descriptor

• Created by factories

• Looked up in an IArtifactRepositoryManager service


Artifact Repository

• An artifact can be stored in multiple forms

• IArtifactKey, is the artifact identifier independently of its form– A key is made of: Classifier, name, version– The key is what an installable unit refers to

• IArtifactDescriptor identifies actual content in a particular form– Location of actual artifact (can be independent of repository

location)– Processing steps necessary to recreate the artifact in the

expected form (e.g. unpack for pack200’ed jars)– Download size, on-disk size, MD5, etc..


Id + version == unique content

• For artifacts and IUs:– Id + version == unique content

• Failing this could result in problems: [1]– Your user does not run the content it should– MD5 or signature verification error at install time

• PDE and p2 help avoid these problems with comparison tools

[1] Andrew’s short talk.


Built-in artifact repositories

• SimpleArtifactRepository– Simple XML format on disk (artifacts.jar / artifacts.xml)– Write (re)writes the entire structure


p2 Architecture

Metadata Artifacts

Runtimes

Profiles

OS

Eclipse

Engine

Eclipse

Classic

Eclipse

for C++

Other

Director Repositories

Touchpoints


The Director Application

A command line app to perform

basic provisioning operations (install / uninstall)

• The director is capable of provisioning a complete installation from scratch or simply extending your application

• Can provision into self or another application

http://wiki.eclipse.org/Equinox_p2_director_application


Running the director

./eclipse

-console -consolelog

-application org.eclipse.equinox.p2.director.app.application

-metadataRepository file:c:/mail/repository

-artifactRepository file:c:/mail/repository

-installIU com.example.mail.product

-destination c:/mail/tmp/ -profile MailProfile

-vmargs -Declipse.p2.data.area=c:/mail/tmp/eclipse/p2


p2 in Action

TransportsHttp/Https

File systemVolume

Repositoriesp2

Update Site

Engine

Eclipse/OSGiNative/OS

Director

ProfilesRuntimes

Provisioning operation requested

Metadata fetched and constraints

analyzed

IU install, uninstall, update

operations

Artifact availability and mirroring

Mirroring

Data transfer

IUs configured into runtimes

Profile updated




Deeper in p2


A p2-enabled application

Because we installed our product, we have a profile and the p2 dialog can come up


What is being run

What's our product all about?


Layout of an installation

Configuration area

p2 data area

Artifact repository index. This allows the plug-ins to be served to other instances.


Configuration data detailed

• Simple configurator provides the OSGi framework the list of bundles to run.

• The information stored in bundles.info is– Location, id, version, start level, started state

Configuration area

Simple configurator data


p2 data area

Download cache, where non-eclipse pieces are mirrored before being installed.

Profile registry

Storage for the profile

Lock file created when the profile is being modified

Current and previous state of the system

MailApp.profile


Profile and profile registry

A profile is the complete description in terms of IU of what is installed

• A profile contains– Properties defining the “environment” such as os, ws, arch, install

location, bundle pool location– The list of IUs– Properties associated with each IUs

• Profiles are held by a profile registry• A profile registry can hold on to several profiles

Class: *.p2.engine.IProfile, IProfileRegistry


Management modes and profile registry

• External mode– The p2 plug-ins are external to the application (e.g an installer)

• Co-hosted mode– The p2 plug-ins are in your application (e.g. the Eclipse SDK).

This mode still allows the application to be externally managed.

• For each case, the profile registry (in fact the p2 data area) can be hosted either in the application being managed or in the managing application.


Changing a profile

• A profile is usually created during the initial installation

• It is changed by provisioning operations performed using:

– The director application

– The API

– The UI

– …




Deeper in p2


Creating an update

Let's make a small change to our product and update the version


Version Numbers

• p2 relies heavily on version numbers

• major.minor.service.qualifier

• Semantics of segment changes

– Major – Breaking API changes

– Minor – New API

– Service – Bug fixes and minor enhancements

– Qualifier – Build id, source control tag• Qualifier is a string

– Typically source control tag

• IU versions should be monotonically increasing


Installing the update


Installing the update

Note that p2 support dynamic addition or removal of bundles. In this case it is the application that is not dynamic.


After the update and restart




Deeper in p2


Creating a new plug-in to install

Don’t forget to specify .qualifier.


Create a feature to deliver our plug-ins

By default p2 UI is not configured to show plug-ins in “Install new software view”. You need to use a feature.


Exporting the feature

How do you create a repository for your exported bundles / features?

You set the option to that effect in the “options” tab.


The publisher

• The publisher is responsible for creating (publishing) repositories from different types of sources

• Bundles and Features Publisher

• UpdateSite Publisher

• Product Publisher

• Category Publisher


Features and Bundles Publisher

./eclipse


-application org.eclipse.equinox.p2.publisher.FeaturesAndBundlesPublisher



-source c:/staging

-append

-publishArtifacts

This will generate metadata for the plug-ins and features found in source.Note that PDE has an option to do it automatically.


Installing the newly created extension



p2 by example

Build and repo managementRepo managementMetadata publication (source and product)Categorizing content

Deeper in p2

© 2009 IBM Corp. and EclipseSource; All right reserved. Made available under Creative Commons Att. Nc Nd 2.5 license

Example: Building with p2

• Import Existing Projects into Workspace

– Select the org.eclipse.pde.build.examples.rcp.cloud.releng.zip archive

– Choose the org.eclipse.pde.build.examples.rcp.cloud.releng project.

• Import Plugins and Fragments

– Import org.eclipse.pde.build as a binary project

• Running the Example

– Run buildProduct.xml as Ant Build using the same JRE as the workspace


Slicing repositories

• The p2.mirror task can easily slice repositories into subset based on given Ius.

• The example requires p2 bundles, as a demonstration we create a new repository containing the contents of the org.eclipse.equinox.p2.user.ui feature, along with a few other bundles.

• Specify IUs to mirror into new location• Set Slicing Options to include the desired dependencies:

– includeOptional : whether to include optional dependencies– followStrict: only follow strict dependencies (eq: [1.0.0.v2009, 1.0.0.v2009]– platformFilter: only mirror Ius matching the given platform filter– includeNonGreedy: mirror non-greedy dependencies

<p2.mirror source="${Eclipse.Repo-3.5M6}" destination="${p2Repo}"> <slicingOptions followStrict="true" /> <iu id="org.eclipse.equinox.p2.user.ui.feature.group" /> <iu id="org.eclipse.ecf"/> <iu id="org.eclipse.ecf.filetransfer"/> .... <iu id="org.apache.ant"/> <iu id="org.eclipse.core.runtime.compatibility.registry"/></p2.mirror>

• The <iu> elements also support a “version” attribute, if this attribute is not specified, the highest version found is mirrored.

[org.eclipse.pde.build.examples.rcp.cloud.releng/buildProduct.xml createP2Repo]


Transforming repositories

• Some bundles must be transformed into folder shape before we can compile against them.

• p2 provides a task that tranforms bundles into their installed shape. PDE Build has built in support for this using the properties:– repoBaseLocation : a folder on disk containing repositories to transform– transformedRepoLocation: the destination repository

<p2.repo2runnable destination="${transformedRepoLocation}"> <source dir="${repoBaseLocation}/" includes="*"/></p2.repo2runnable>

<source> elementsNested <source> elements are ant filesets that support an extra attribute “location”• The “location” attribute specifies a URL to a repository used for both metadata and

artifacts• If no “location” attribute is specified:

• folders matched by the fileset are loaded as repositories

• Files ending in “.zip” are loaded as zipped repositories

<iu> elementsNested <iu> elements specify specific IUs to transform• If no <iu> elements are specified, the entire repository is transformed

[org.eclipse.pde.build/scripts/genericTargets.xml transformRepos]


p2 by example


Deeper in p2


Publishing metadata

• Publishing from Source

• PDE Build extends the publisher and provides an ant tasks to publish to repositories directly from the source for a bundle or feature:

– Source contains more inputs that can be used to generate metadata (build.properties, p2.inf)

– Features can have rootfile IUs and artifacts associated with them– Allows for some performance gains when over 3.4 style metadata generation.

Publishing from Binaries

The publisher provides an ant task to publish metadata from binary jars:

<p2.publish.featuresAndBundles repository="file:C:/dev/repo"> <bundles dir="C:\eclipse\plugins" includes="org.eclipse.equinox.launcher_1.0.200.v20090306-1900.jar" /> <features dir="C:\eclipse\features" includes="org.eclipse.rcp_3.5.0.v20090307-9RA-FqhFstOCxSdfkxdojLKc"/></p2.publish.featuresAndBundles>

Both the <bundles> and <features> nested elements are ant filesets specifying folders and jars to publish.

PDE Build has an equivalent task “eclipse.publish.featuresAndBundles” which does the same but also supports a “site” attribute for category generation.

[org.eclipse.pde.build.examples.rcp.cloud.releng/buildDirectory/assemble.org.eclipse.pde.build.container.feature.win32.win32.x86.xml]


Publishing Products

• Branding Artifacts

• PDE Build supports branding artifacts. This will– Download input artifact, generally artifacts from org.eclipse.equinox.executable– Brand the executable and replace icons– Republish the branded artifact using the product id and version

[org.eclipse.pde.build.examples.rcp.cloud.releng\buildDirectory\assemble.org.eclipse.pde.build.container.feature.p2.xml <eclipse.brand.p2.artifacts>]

Publishing the Product

The publisher provides an ant task to publish products using a .product file. Allows publishing of products without running a build, provided all required IUs already exist in

the repository [org.eclipse.pde.build.examples.rcp.cloud.releng\buildDirectory\assemble.org.eclipse.pde.build.container.feature.p2.xml <p2.publisher.product>]

Default Configuration IUs

PDE Build will generate default configuration IUs for :• Setting default start levels

• Including equinox launchers, setting -startup - -launcher.library

[org.eclipse.pde.build.examples.rcp.cloud.releng\buildDirectory\features\org.eclipse.pde.build.container.feature\product\p2.inf]


Running the Director

<java jar="${equinoxLauncherJar}" fork="true" failonerror="true"><arg line="-application org.eclipse.equinox.p2.director.app.application" /><arg line="-nosplash" /><arg line="--launcher.suppressErrors" /><arg line="-consoleLog" /><arg line="-flavor ${p2.flavor}" /><arg line="-installIU ${p2.director.iu}" /><arg line="-version ${p2.director.version}" /><arg line="-p2.os ${os}" /><arg line="-p2.ws ${ws}" /><arg line="-p2.arch ${arch}" /><arg line="-roaming" /><arg line="-profile ${p2.director.profile}" /><arg line="${p2.director.extraArgs}" /><arg line="-metadataRepository"/><arg value="${p2.repo}" /><arg line="-artifactRepository"/><arg value="${p2.repo}" /><arg line="-destination"/><arg value="${p2.director.installPath}" /><arg line="-bundlepool"/><arg value="${p2.director.bundlepool}" />

<jvmarg value="-Declipse.p2.data.area=${p2.director.dataArea}" /><jvmarg line="${p2.director.extraVMArgs}" />

</java>

• PDE Build now automatically invokes the director for properly configured product builds.(see org.eclipse.pde.build/scripts/genericTargets.xml/runDirector)

[org.eclipse.pde.build/scripts/genericTargets.xml runDirector]


p2 by example


Deeper in p2


Categorizing repository content

We define categories using site.xml or category.xml


Creating the category


Categorizing our feature



UpdateSite Publisher

./eclipse


-application org.eclipse.equinox.p2.updatesite.UpdateSitePublisher



-source C:\staging\updateSite\com.example.mail.updatesite

-append

-publishArtifacts

When using the category.xml, use the org.eclipse.equinox.p2.publisher.CategoryPublisher



p2 by example


Deeper in p2Additional p2 constructs

From plug-ins and features to metadata

Plug-ins map

Reusing and tweaking the UI

Advanced concepts


Installable Unit Fragments

• An installable unit fragment is an entity that attaches to an installable unit.

• Much like OSGi fragments, IU fragments are used to complement an existing installable unit and appear as one with the IU they attached to.

• They are typically used to deliver configuration information to an installable unit (e.g. start level).

• IU fragments can be attached to several IU at the same time. See for example the tooling.osgi.bundle.default IU that applies to all bundles.

• Note that IU fragments are not how OSGi fragments are delivered. OSGi fragments are delivered as regular IU with requirements on their host.

Class: IInstallableUnitFragment


Installable Unit Patches

• An installable unit patch has the ability to “modify” the requirements of any other installable unit.

• Deal with three concerns:– The IUs to which the patch apply

– The lifecycle of patch

– The changes applied

Note: In 3.5 the feature patch editor only exposes some of those capabilities.

See also http://aniefer.blogspot.com/2009/06/patching-features-with-p2.html


Installable Units

• There is only 3 kinds of IU:– InstallableUnit, InstallableUnitFragment and InstallableUnitPatch

• To ease the discussion we use the following terms:– Group IU: any IU with the group property set to true. It usually results

from the metadata generated for a feature.

– Product IU: an representing the root of a product (e.g. org.eclipse.sdk.ide). It usually results from the metadata generated for a product.

– CU: an IU Fragment carrying configuration information (e.g. start level)


p2 by example




Plug-ins map


Advanced concepts


Understanding the metadata generated

• Feature– A feature results in two IUs: one capturing the dependencies to other plug-ins

and features and one IU representing the feature.jar. – Note that ids for the feature being generated are suffixed:

org.eclipse.rcp org.eclipse.rcp.feature.group & org.eclipse.rcp.feature.jar

• OSGi bundle

– One IU provides capabilities for :• each exported package, • indicating that it is a bundle• Indicating its bundle name

<provided namespace='osgi.bundle' name='org.apache.commons.codec' version='1.3.0'/><provided namespace='java.package' name='org.apache.commons.codec' version='1.3.0'/><provided namespace='java.package' name='org.apache.commons.codec.binary' version='1.3.0'/><provided namespace='java.package' name='org.apache.commons.codec.digest' version='1.3.0'/><provided namespace='java.package' name='org.apache.commons.codec.language' version='1.3.0'/><provided namespace='java.package' name='org.apache.commons.codec.net' version='1.3.0'/><provided namespace='org.eclipse.equinox.p2.eclipse.type' name='bundle' version='1.0.0'/>


Understanding the metadata generated

• OSGi fragment– Same as OSGi bundle plus a capability indicating it is a fragment. The

requirement on the host become regular dependencies

• The exe– An IU

• The config.ini and eclipse.ini– Pure metadata. The files are not downloaded they are the result of the

installation.

– Several InstallableUnitFragments (e.g. toolingorg.eclipse.equinox.launcher or toolingorg.eclipse.equinox.simpleconfigurator).

<provided namespace='osgi.fragment' name='org.eclipse.swt' version='3.5.0.v3536b'/><provided namespace='osgi.bundle' name='org.eclipse.swt.win32.win32.x86' version='3.5.0.v3536b'/>

It is important to remember that this is only the metadata generated by the applicationsprovided as part of the publisher, but the metadata is generic and is yours to extend.


p2 by example




Plug-ins map


Advanced concepts


Plug-ins map

ECFE

clip

se

touc

hpoi

nt

Nat

ive

touc

hpoi

nt

Too

ling

OSGi

Upd

ate

site

re

posi

tory

engine

Metadata

Director

Repository

UI …

…


The minimal set of plug-ins required to provision with p2. They define the core p2 concepts.

• core– Provides some basic infrastructure for most plug-ins. It defines Query, Version

and other helpers.

• metadata– Defines the interfaces for the metadata:

IInstallableUnit, IUFragment, IUPatch

• engine– Executes a set of operations against a profile. Engine.perform(…)– Defines the concept of touchpoint and action: ProvisioningAction– Defines profile preference scope– Contains the download manager (should not be here)

• director– Implements the resolution mechanism of p2. Depends on the org.sat4j.*

bundles.

Core plug-ins (1/2)


Core plug-ins (2/2)

• repository– Defines concept of Repository and repository manager. Interfaces with ECF.

• metadata.repository– Defines the metadata repository API and the repository manager.– Implements the simple metadata repository (content.jar / content.xml), composite metadata

repository. – Ant tasks: p2.composite.* to manage composite repos.– Application: org.eclipse.equinox.p2.metadata.repository.mirrorApplication.

• artifact.repository– Same than metadata repository for artifacts. – Implements processing steps for MD5, pack200 and zipVerifier.– Ant tasks: p2.artifact.mirror, p2.composite.artifact.* to manage composite repos [1].– Application: org.eclipse.equinox.p2.artifact.repository.mirrorApplication.

• garbagecollector– Basic garbage collector loop and extension point. – Repository and touchpoint agnostic.

• examplarysetup– The plug-in of shame. Pulling all the pieces together.

[1] - Ant task - http://wiki.eclipse.org/Equinox/p2_Ant_Tasks


Transport related plug-ins

p2 uses ECF because it offers pluggable transport.

• org.eclipse.equinox.p2.repository– Interfacing of p2 with ECF

• org.eclipse.ecf, org.eclipse.ecf.identity,org.eclipse.ecf.ssl– Core ECF bundles

• org.eclipse.ecf.filetransfer– Defines the interface to transfer file with ECF

• org.eclipse.ecf.provider.filetransfer, org.eclipse.ecf.provider.filetransfer.ssl

– Provides the implemtation of the service defined in ecf.filetransfer

• org.eclipse.ecf.provider.filetransfer.httpclient, org.eclipse.ecf.provider.filetransfer.httpclient.ssl

– Interface ECF with org.apache.commons.httpclient

• org.apache.commons.httpclient– The http client from apache (in 3.5 we are using the 3.0.1 implementation)


Eclipse management

• touchpoint.eclipse– Defines the touchpoint and actions necessary to install into eclipse

(setStartLevel, installBundle, etc). See [1]

• fwkadmin– Abstract the eclipse touchpoint from the implementation details of a particular

OSGi framework.

• fwkadmin.equinox– Implementation of the fwkadmin API for the Equinox framework. It knows how to

reason about config.ini and eclipse.ini

• simpleconfigurator.manipulator– Bundles.info writer.

• simpleconfigurator– This bundle is used on startup to tell the OSGi framework what to run. It reads

the bundles.info file located in configuration/org.eclipse.equinox.simpleconfgurator/bundles.info

[1] – Actions defined by eclipse touchpoint - http://wiki.eclipse.org/Equinox/p2/Engine/Touchpoint_Instructions


Native support

• touchpoint.natives– Defines actions such as chmod, link, unzip, etc. [1]

[1] – Actions defined by native touchpoint - http://wiki.eclipse.org/Equinox/p2/Engine/Touchpoint_Instructions


UI plug-ins

Bundles usable in an eclipse-based application.

• ui– Implementation of the install dialog and wizards.

• ui.sdk (bogus name alert)

– Integration of p2 in an application: contribution in the help menu and preference page.

• ui.sdk.scheduler (bogus name alert)

– UI affordance and preference page for the update checker.

• updatechecker– Provides the ability to check for an update. This is not a UI bundle.


Repositories implementation

p2 allows for alternate repository implementation. Here are few additional ones that are provided.

• extensionlocation– Support to recognize as a repository folders containing the sub folders plugins/

and features

• directorywatcher– Support plug-in for the extension location repository. Monitors the content of the

plug-ins folder.

• updatesite– Support for Eclipse legacy update sites.

• reconciler.dropins– Install all the plug-ins and features found into the dropins/ folder. This is not a

repository in itself.


Misc management bundles

• director.app– Provides a headless way of managing an installation (install / uninstall).– App.: org.eclipse.equinox.p2.director.app.application [1]

• installer– Provides an exemplary simple installer using an SWT-based UI.

[1] – Director application doc - http://wiki.eclipse.org/Equinox_p2_director_application


Tooling plug-ins

Applications and tasks are provided to generate metadata and manage repository

• publisher– A modular and extensible mechanism to generate metadata.– Application: org.eclipse.equinox.p2.publisher.*,

FeaturesAndBundlesPublisher– Ant tasks: p2.publish.product, p2.publish.featureAndBundles,

p2.publisher

• metadata.generator (deprecated in 3.5)

– Generate metadata from an exported product.

• repository.tools– Provides a set of tools to manage repositories

• Ant tasks: p2.mirror, p2.repo2Runnable, [1]• …

• jarprocessor– Helper tool to sign and pack jars

[1] - Ant task - http://wiki.eclipse.org/Equinox/p2_Ant_Tasks


p2 by example




Plug-ins map


Advanced concepts


Tweaking the p2 UI for your audience

• The UI is split into 3 bundles.– p2.ui– p2.ui.sdk

• Integration

– p2.ui.sdk.scheduler• Scheduler


Add a p2 Preference Page

• The p2 UI defines a number of preferences– Automatic Updates– Site selection

• We need to add a preference page to our RCP application


Adding Automated Updates and other p2 Preferences

Since the p2 bundles are installed, the p2 preferences can be used.


Remove automatic updates

• Eliminate:– org.eclipse.equinox.p2

.ui.sdk.scheduler– org.eclipse.equinox.p2

.updatechecker

• RCP Mail no longer supports automatic updates


Customizing the UI

• Consider which bundles you need– Always include org.eclipse.equinox.p2.ui– If you wish to use automatic update checking,

include org.eclipse.equinox.p2.updatechecker– If you wish to reuse the SDK UI for automatic update include

org.eclipse.equinox.p2.ui.sdk.scheduler

• Configure an instance of org.eclipse.equinox.internal.provisional.p2.ui.policy.Policy


Example – Control the Update

• Let’s lock down the application

• Register a new profile– Does not allow users to add sites– Group IUs by category


Example – Control the Update


The controlled mode

Notice that the entry to choose a site is not available.

The preference page to add repo is also removed.


Granularity of what is visible

• By default, the p2 UI shows installed roots– Configure the UI to show all installed bundles– Remove the install history page– Reconfigure the installed software page

• i.e. to remove update


Granularity of what is visible


Updating on Startup

Activator startup code must ensure that the p2 infrastructure bundles are started. Otherwise, the required services may not be found when updates are checked.


UI code snippets

• All the p2 UI examples are available at:http://wiki.eclipse.org/Equinox/p2/Adding_Self-Update_to_an_RCP_Application

• In CVSdev.eclipse.org/cvsroot/rt

org.eclipse.equinox/p2/examples


p2 by example




Plug-ins map


Advanced concepts


Queryable / Query

• IQueryable is a general interface for a collection of objects that can be queried

• Query is what you want to see found– Mostly used to find installable units

• In p2 everything dealing with IUs is queryable– MetadataRepository, Profile, result of query…

• Some default queries are provided (see implementors of Query)– InstallableUnitQuery: To find an IU matching an ID and or a version– CapabilityQuery: To find an IU providing a capability matching a given requirement– IUPropertyQuery: To find an IU with a given property– VersionLatestIUVersionQuery: To find the most recent IU


Profile

A profile is the complete description in terms of IU of what is installed

• A profile contains– Properties defining the “environment” such as os, ws, arch,

install location, bundle pool location– The list of IUs– Properties associated with IUs

Class: Org.eclipse.equinox.internal.provisional.p2.engine.IProfile


Planning a profile change

Because of inter IU dependencies, modification against a profile should be planned

• ProfileChangeRequest– Capture the changes you want to make to the profile (e.g. Install, Uninstall).– The request is processed by the Planner– An update is a removal and an addition

• Planner– The entity responsible for the evaluation of the change request, computing the

transitive closure and checking the dependencies– If a solution exists it will find it

• ProvisioningPlan– The planner returns a provisioning plan. The planning succeed pass or fail. Upon

failure explanations are provided. Upon success the plan returns a set of operands to go from the initial state of the profile to the desired state.


Engine

The mechanism by which the profile is actually changed

• Runs over a set of operands (usually resulting from a planning operation) and executes a given set of phases on them. No profile consistency validation is done

Engine.perform(Operand[] ops, PhaseSet phases, IProgressMonitor pm)

• For each phase, the engine interprets from the touchpoint data of the IU, the action specific to the phase. The engine looks up the action to execute.

• Currently 8 phases are defined, and the typical set of phases (and their order) is defined in DefaultPhaseSet. The design allows for new phases could be added, however this would engage serious coding.

• The engine ensures consistency of the modification by performing a “transaction”.

• The engine emit events on the IProvisoningEventBus to describe what is happening. Events on the bus are post events and can not be vetoed.


Engine flowchart


Touchpoint / actions

The decoupling between p2 and the actual system being modified.

It defines how to modify a particular “runtime”.

• An action is a piece of code in charge of changing the system (e.g installing a bundle, setting a start level, etc.). An action can be context free or context bound. See ProvisioningAction

– Example of context free: chmod, unzip– Example of context bound: installBundle, setStartLevel,…

• A touchpoint provides the context in which an action is executed– For example the eclipse touchpoint provides its actions values such as the eclipse

install folder, the bundle pool and is also used to cache some common data structure (e.g. the state of the fwk being modified)

• The extension point for touchpoint and actions is defined in the engine.


Engine and actions put together


Artifact processor

• Artifacts can be stored in various format (e.g. pack200, jar, diff)

• A processor is responsible for transforming an artifact from its “stored” form to its canonical form.

• Processors can also be used to “look at” the bytes as they are coming through

– MD5, zip verifier,

• Mandatory steps are mentioned in the artifact descriptor in the artifact repository

– <example>

• Implementation detail:– The download manager looks at the various shapes under which an artifact is made

available and always prefer the non-canonical one.

• Extension point: org.eclipse.equinox.p2.artifactRepository.ProcessingStep


Canonical

JBDiff

Artifact Repository

Pack200

Pack200Processor

Artifact processor, illustrated


References

• p2 landing page http://wiki.eclipse.org/Equinox_p2

• All p2 articles http://wiki.eclipse.org/Category:Equinox_p2

• Getting the code http://wiki.eclipse.org/Equinox_p2_Getting_Started_for_Developers

• Contacting us– Equinox newsgroup– Mailing list: [email protected]


Thank you


F.A.Q.


Bundle Pooling

• Every profile has a bundle pool location

• Shared pool → multiple profiles share bundles

• Save download time/bandwidth

• Save disk space

• Possible memory savings depending on JRE

• Can be setup with installer or admin UI


Installing just a plug-in

It is possible, just grab the IU and install it. The default p2 UI is not allowing for this to not overwhelm users To have p2 metadata for it, you still have to have a feature (PDE

restriction)


Boot sequence

• Without dropins– Simpleconfigurator reads bundles.info and apply it (note that if

bundles.info has not changed, nothing is done).– p2 bundles are not loaded until p2 functionality is invoked (e.g

open the UI)

• With dropins – Simpleconfigurator reads bundles.info and apply it (note that if

bundles.info has not changed, nothing is done).– Reconciler bundles is started– Reconciler finds the bundles in the dropins folder and take them

through a complete installation phase. A new profile file and a new bundles.info are written

– Reconciler re-invoke simpleconfigurator to read bundles.info


Missing requirements

• The cause of an error indicating a missing requirement usually are:– Missing capabilities: no IU in the repository provides the

capability necessary to the satisfaction of the requirement.– Bogus filter on the IU that could satisfy the requirement– Missing IU: the IU satisfying the requirement is not available in

the repositories being consulted

Technology

Understanding and extending p2 for fun and profit