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Difference between revisions of "Tycho/Target Platform"

(update links to target editor documentation to Juno; remove target file example which goes into too much detail for a target platform overview page)
m (The tycho demo repository no longer exists)
 
(24 intermediate revisions by 8 users not shown)
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There are different ways to define the content of the target platform; the most common ones are repositories with layout=p2 in the POM, which add entire p2 repositories to the target platform, or target definition files for more fine-grained control.
 
There are different ways to define the content of the target platform; the most common ones are repositories with layout=p2 in the POM, which add entire p2 repositories to the target platform, or target definition files for more fine-grained control.
  
=== Which approach should I use for the target platform for my project? ===
+
== Which approach shall I use for the target platform of my project? ==
  
Since there are a few different ways to configure a target platform in Tycho, here are some rules of thumb for the most common cases:
+
There are a few different ways to configure a target platform in Tycho. These rules of thumb should help you to pick the right approach for your project:
# If you are already using a target file in Eclipse, and that target file only contains <tt>location</tt> elements with <tt>type="InstallableUnit"</tt>, use that target file for the Tycho build. This approach is the only way to share the same target platform configuration between Tycho and Eclipse.
+
# If you are already using a target file in Eclipse, and that target file only contains "Software Site" locations (i.e. <tt>location</tt> elements with <tt>type="InstallableUnit"</tt>), use that target file for the Tycho build. This approach is the only way to share the same target platform configuration between Tycho and Eclipse.
# If you don't care about individual bundles and versions, just configure the needed p2 repositories in the POM and have Tycho pick anything required from these repositories.
+
# If you want to get your Tycho build up and running quickly, just configure the needed p2 repositories in the POM and have Tycho pick anything required from these repositories. A good starting point should be to add one of the [[Eclipse Project Update Sites#Simultaneous_Release_repositories|Simultaneous Release repositories]].
# If you want control over the which bundles/bundle versions are visible to the build, use a target file.
+
# If you want to exert control over the which bundles/bundle versions may be used by the build, use a target file and have it select the sub-set of features and bundles from a p2 repository that you want. Using a target file instead of p2 repositories in the POM may also speed up the build because fewer bundles in the target platform will often lead to a faster dependency resolution.
  
=== Target platform configuration ===
+
== Target platform configuration ==
  
 
The target platform is defined through POM configuration (see details below). Each module has its own target platform, although with the normal configuration inheritance in Maven, the target platform configurations are usually the same across multiple modules.
 
The target platform is defined through POM configuration (see details below). Each module has its own target platform, although with the normal configuration inheritance in Maven, the target platform configurations are usually the same across multiple modules.
  
 
<div id="Layout_p2">
 
<div id="Layout_p2">
==== Simple target platform configuration ====
+
=== Simple target platform configuration ===
  
 
In order allow Tycho to resolve the project dependencies against anything from a specific p2 repository, add that repository in the <tt>&lt;repositories&gt;</tt> section of the POM. Example:
 
In order allow Tycho to resolve the project dependencies against anything from a specific p2 repository, add that repository in the <tt>&lt;repositories&gt;</tt> section of the POM. Example:
Line 33: Line 33:
 
</div>
 
</div>
  
==== Target files ====
+
=== Target files ===
  
The PDE target definition file format (*.target) allows to select a subset of units (bundles, features, etc.) from one or more p2 repositories. In order to add the content of a target definition file (see "Content" tab of the Target Editor) to the target platform in the Tycho build, configure the target file in the <tt>target-platform-configuration</tt> build plugin. Example:
+
The PDE target definition file format (*.target) allows to select a subset of units (bundles, features, etc.) from one or more p2 repositories. In order to add the content of a target definition file (see "Content" tab of the Target Editor) to the target platform in the Tycho build, place the target file in a [[Tycho/Packaging Types#eclipse-target-definition|eclipse-target-definition]] module and configure it in the <tt>target-platform-configuration</tt> build plugin. Example:
 
<pre>
 
<pre>
 
<plugin>
 
<plugin>
Line 47: Line 47:
 
             <artifactId>target-definition</artifactId>
 
             <artifactId>target-definition</artifactId>
 
             <version>1.0.0-SNAPSHOT</version>
 
             <version>1.0.0-SNAPSHOT</version>
            <classifier>targetFileNameWithoutExtension</classifier>
 
 
         </artifact>
 
         </artifact>
 
       </target>
 
       </target>
Line 53: Line 52:
 
</plugin>
 
</plugin>
 
</pre>
 
</pre>
The target definition file then needs to be placed in the root of project with the specified GAV.
 
  
'''Note:''' Tycho has only limited support for target definition files:
+
Since Tycho 0.17.0, it is also possible to configure multiple target files by specifying more than one <tt>&lt;artifact&gt;</tt> reference. Tycho interprets these target files independently and in the same way as in Eclipse: Each of the configured target files need to resolve successfully when opened in the Eclipse Target Editor. Note that the use of this Tycho feature is limited because the Eclipse PDE currently does ''not'' support activating more than one target file at once (see [https://bugs.eclipse.org/bugs/show_bug.cgi?id=392652 bug 392652]).
* The location types "Directory", "Installation", and "Features" are not supported.
+
 
* The selection on the Content tab of the Target Editor is ignored, i.e. it is not possible to de-select individual bundles for the Tycho target platform.
+
<p>'''Note:''' Tycho's interpretation of the target definition file format differs from the PDE in the following aspects:
* The option "Include source if available" is not supported.
+
* The selection on the Content tab of the Target Editor is ignored. [[#Filtering|See below]] for an alternative way to remove individual bundles from the target platform.
 +
* The option "Include source if available" is considered only if <tt>target-platform-configuration</tt> parameter <tt>targetDefinitionIncludeSource</tt> is set to <tt>honor</tt> (default value). If <tt>targetDefinitionIncludeSource</tt> is set to <tt>force</tt> then available sources are always included and if set to <tt>ignore</tt> then available sources are always ignored.
 +
</p>
  
 
<p>'''Related Information'''
 
<p>'''Related Information'''
Line 64: Line 64:
 
</p>
 
</p>
  
==== "POM dependencies consider" ====
+
<div id="POM_Dependencies">
  
OSGi bundles from Maven repositories can be added to the target platform in the following way:
+
=== Extra requirements ===
# Specify a dependency to the OSGi bundle artifact in the POM's <tt>&lt;dependencies&gt;</tt> section.
+
# Set the configuration parameter <tt>pomDependencies</tt>=<tt>consider</tt> on the <tt>target-platform-configuration</tt> plugin
+
  
This configuration has the following effect:
+
See https://ci.eclipse.org/tycho/job/tycho-sitedocs/lastSuccessfulBuild/artifact/target/staging/target-platform-configuration/target-platform-configuration-mojo.html#dependency-resolution
* First, Maven resolves the GAV dependencies according to the normal Maven rules. This results in a list of artifacts consisting of the specified artifacts and their transitive Maven dependencies.
+
* Tycho then considers each of these artifacts for the target platform: if the artifact is an OSGi bundle, it is added to the target platform. Other artifacts are ignored. OSGi bundles which become part of the target platform in this way are then available to resolve the project's OSGi dependencies.
+
  
For an example, see the POM of this [http://git.eclipse.org/c/tycho/org.eclipse.tycho.git/tree/tycho-demo/itp02/build02 demo project].
+
=== "POM dependencies consider" ===
  
=== Effective content of the target platform ===
+
See https://www.eclipse.org/tycho/sitedocs/target-platform-configuration/target-platform-configuration-mojo.html#pomDependencies .
  
In case multiple target platform configuration approaches are combined (which should be rarely necessary), the target platform contains the union of the content defined through each approach.
+
For an example, see the POM of this [https://github.com/eclipse/tycho/blob/master/demo/itp02/build02 demo project].
 +
 
 +
== Effective content of the target platform ==
 +
 
 +
In case multiple target platform configuration approaches are combined, the target platform contains the union of the content defined through each approach.
  
 
Apart from the explicitly configured content, the target platform also contains the following artifacts:
 
Apart from the explicitly configured content, the target platform also contains the following artifacts:
Line 84: Line 84:
 
* Locally built artifacts in the local Maven repository
 
* Locally built artifacts in the local Maven repository
  
TODO Option to exclude locally built artifacts from the target platform ([https://bugs.eclipse.org/bugs/show_bug.cgi?id=355367 bug 355367])
+
Finally, it is possible to remove artifacts again from the target platform through a filtering syntax.
  
==== Filtering ====
+
=== Locally built artifacts ===
  
Since [[Tycho/Release Notes/0.14|Tycho 0.14.0]], it is possible to selectively remove content from the target platform. This for example allows to restrict the version of a bundle, or to select one particular provider for a package. Filtering is done as last step in the target platform computation, so the filters apply to all sources listed above.
+
Just like in a normal Maven build, a Tycho build can use artifacts that have been built locally and installed (e.g. with <tt>mvn clean install</tt>) into the local Maven repository. In terms of the target platform, this means that these artifacts are implicitly added to the target platform. This is for example useful if you want to rebuild a part of a Tycho reactor, or if you want to build against a locally built, newer version of an upstream project.
  
The filters are specified in the <tt>target-platform-configuration</tt> build plugin:
+
There are the following options to disable this feature:
<pre>
+
* Setting the CLI option <tt>-Dtycho.localArtifacts=ignore</tt> excludes locally built artifacts in one build. (<tt>tycho.localArtifacts=ignore</tt> may also be configured in the <tt>settings.xml</tt>; in this case, the default behaviour can be temporarily re-enabled with the CLI option <tt>-Dtycho.localArtifacts=default</tt>. Since Tycho 0.16.0.)
<plugin>
+
* Deleting <tt>~/.m2/repository/.meta/p2-local-metadata.properties</tt> resets Tycho's list of locally build artifacts, and therefore these artifacts will not be added to target platforms (unless, of course, the artifacts are installed again).
  <groupId>org.eclipse.tycho</groupId>
+
  <artifactId>target-platform-configuration</artifactId>
+
  <version>${tycho-version}</version>
+
  <configuration>
+
      <filters>
+
  
        <!-- example 1: restrict version of a bundle -->
+
=== Filtering ===
        <filter>
+
            <type>eclipse-plugin</type>
+
            <id>org.eclipse.osgi</id>
+
            <restrictTo>
+
              <versionRange>[3.6,3.7)</versionRange> <!-- alternative: <version> for selecting exactly one versions -->
+
            </restrictTo>
+
        </filter>
+
 
+
        <!-- example 2: remove all providers of the package javax.persistence except the bundle javax.persistence -->
+
        <filter>
+
            <type>java-package</type>
+
            <id>javax.persistence</id>
+
            <restrictTo>
+
              <type>eclipse-plugin</type>
+
              <id>javax.persistence</id>
+
            </restrictTo>
+
        </filter>
+
 
+
        <!-- example 3: work around Equinox bug 348045 -->
+
        <filter>
+
            <type>p2-installable-unit</type>
+
            <id>org.eclipse.equinox.servletbridge.extensionbundle</id>
+
            <removeAll />
+
        </filter>
+
      </filters>
+
  </configuration>
+
</plugin>
+
</pre>
+
  
'''Notes''':
+
See https://ci.eclipse.org/tycho/job/tycho-sitedocs/lastSuccessfulBuild/artifact/target/staging/target-platform-configuration/target-platform-configuration-mojo.html#filters
* The filters will only remove content from the target platform; they will not add new content. If you specify a restriction that is not fulfilled by any of the units from the target platform sources, all units that the filter applies to (i.e. units that match the <tt>filter.type</tt>, <tt>filter.id</tt>, and <tt>filter.version/versionRange</tt> criteria) will be removed from the target platform.
+
* Package provider restrictions work by removing all other bundles exporting the package. This means that these other bundles (and the packages only exported by them) won't be available in your build.
+
  
=== Dependency resolution troubleshooting ===
+
== Dependency resolution troubleshooting ==
  
 
TODO  
 
TODO  
  
Run mvn with "-Dtycho.debug.resolver=true -X" to see debug output.
+
Run mvn with the flags <tt>-Dtycho.debug.resolver=true</tt> and <tt>-X</tt> to see debug output.
  
 
This will debug
 
This will debug
Line 145: Line 110:
 
* Root IUs
 
* Root IUs
  
==== Listing IUs available ====
+
=== Listing IUs available ===
  
 
To list all the available IUs in an Eclipse repository (e.g. indigo), run:
 
To list all the available IUs in an Eclipse repository (e.g. indigo), run:
Line 151: Line 116:
 
<pre>
 
<pre>
 
$ java -jar plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar -debug -consolelog -application org.eclipse.equinox.p2.director -repository http://download.eclipse.org/releases/indigo/ -list
 
$ java -jar plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar -debug -consolelog -application org.eclipse.equinox.p2.director -repository http://download.eclipse.org/releases/indigo/ -list
 +
</pre>
 +
 +
Command running with Luna and list Luna Repository
 +
<pre>
 +
$ java -jar plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar -debug -consolelog -application org.eclipse.equinox.p2.director -repository http://download.eclipse.org/releases/luna/ -list
 
</pre>
 
</pre>
  
Line 159: Line 129:
  
 
This can be used to double check availability of bundle versions, and compare with what Nexus thinks is available with the source Eclipse repository.
 
This can be used to double check availability of bundle versions, and compare with what Nexus thinks is available with the source Eclipse repository.
 +
 +
=== Browsing a p2 repository ===
 +
 +
* In Eclipse, open the "Repository Explorer" view. If it is not available, then please install Oomph first: https://projects.eclipse.org/projects/tools.oomph/downloads
 +
* There is also a graphical p2 browser (java webstart app) available on [https://github.com/ifedorenko/p2-browser github].
 +
Just follow the instructions in the README to start it.
  
 
[[Category:Tycho|Target Platform]]
 
[[Category:Tycho|Target Platform]]

Latest revision as of 01:39, 20 July 2021

The target platform is the set of artifacts from which Tycho resolves the project's dependencies.

Background: OSGi allows to specify dependencies with version ranges and package dependencies (Import-Package). These dependencies (intentionally) do not map to unique artifacts. In order to pick a set of concrete bundles to be used for compilation, test execution, and assembly, Tycho needs a set of candidate artifacts which may be used to match the dependencies. This list of candidate artifacts is called the "target platform". The process of selecting artifacts from the target platform according to the project's dependencies is called "dependency resolution".

There are different ways to define the content of the target platform; the most common ones are repositories with layout=p2 in the POM, which add entire p2 repositories to the target platform, or target definition files for more fine-grained control.

Which approach shall I use for the target platform of my project?

There are a few different ways to configure a target platform in Tycho. These rules of thumb should help you to pick the right approach for your project:

  1. If you are already using a target file in Eclipse, and that target file only contains "Software Site" locations (i.e. location elements with type="InstallableUnit"), use that target file for the Tycho build. This approach is the only way to share the same target platform configuration between Tycho and Eclipse.
  2. If you want to get your Tycho build up and running quickly, just configure the needed p2 repositories in the POM and have Tycho pick anything required from these repositories. A good starting point should be to add one of the Simultaneous Release repositories.
  3. If you want to exert control over the which bundles/bundle versions may be used by the build, use a target file and have it select the sub-set of features and bundles from a p2 repository that you want. Using a target file instead of p2 repositories in the POM may also speed up the build because fewer bundles in the target platform will often lead to a faster dependency resolution.

Target platform configuration

The target platform is defined through POM configuration (see details below). Each module has its own target platform, although with the normal configuration inheritance in Maven, the target platform configurations are usually the same across multiple modules.

Simple target platform configuration

In order allow Tycho to resolve the project dependencies against anything from a specific p2 repository, add that repository in the <repositories> section of the POM. Example:

<repository>
   <id>eclipse-indigo</id>
   <url>http://download.eclipse.org/releases/indigo</url>
   <layout>p2</layout>
</repository>

In terms of the target platform, this means that the entire content of the p2 repositories specified in this way become part of the target platform.

Background: In a normal (i.e. non-Tycho) Maven project, one can configure Maven repositories which can be used by Maven to resolve the project dependencies. While Maven repositories cannot be used directly (see below for an indirect approach), Tycho can use p2 repositories for resolving OSGi dependencies. The p2 repositories need to be marked with layout=p2. (The normal Maven dependency resolution ignores repositories with layout=p2.)

Target files

The PDE target definition file format (*.target) allows to select a subset of units (bundles, features, etc.) from one or more p2 repositories. In order to add the content of a target definition file (see "Content" tab of the Target Editor) to the target platform in the Tycho build, place the target file in a eclipse-target-definition module and configure it in the target-platform-configuration build plugin. Example:

<plugin>
   <groupId>org.eclipse.tycho</groupId>
   <artifactId>target-platform-configuration</artifactId>
   <version>${tycho-version}</version>
   <configuration>
      <target>
         <artifact>
            <groupId>org.example</groupId>
            <artifactId>target-definition</artifactId>
            <version>1.0.0-SNAPSHOT</version>
         </artifact>
      </target>
   </configuration>
</plugin>

Since Tycho 0.17.0, it is also possible to configure multiple target files by specifying more than one <artifact> reference. Tycho interprets these target files independently and in the same way as in Eclipse: Each of the configured target files need to resolve successfully when opened in the Eclipse Target Editor. Note that the use of this Tycho feature is limited because the Eclipse PDE currently does not support activating more than one target file at once (see bug 392652).

Note: Tycho's interpretation of the target definition file format differs from the PDE in the following aspects:

  • The selection on the Content tab of the Target Editor is ignored. See below for an alternative way to remove individual bundles from the target platform.
  • The option "Include source if available" is considered only if target-platform-configuration parameter targetDefinitionIncludeSource is set to honor (default value). If targetDefinitionIncludeSource is set to force then available sources are always included and if set to ignore then available sources are always ignored.

Related Information

Extra requirements

See https://ci.eclipse.org/tycho/job/tycho-sitedocs/lastSuccessfulBuild/artifact/target/staging/target-platform-configuration/target-platform-configuration-mojo.html#dependency-resolution

"POM dependencies consider"

See https://www.eclipse.org/tycho/sitedocs/target-platform-configuration/target-platform-configuration-mojo.html#pomDependencies .

For an example, see the POM of this demo project.

Effective content of the target platform

In case multiple target platform configuration approaches are combined, the target platform contains the union of the content defined through each approach.

Apart from the explicitly configured content, the target platform also contains the following artifacts:

  • Other artifacts from the same reactor
  • Locally built artifacts in the local Maven repository

Finally, it is possible to remove artifacts again from the target platform through a filtering syntax.

Locally built artifacts

Just like in a normal Maven build, a Tycho build can use artifacts that have been built locally and installed (e.g. with mvn clean install) into the local Maven repository. In terms of the target platform, this means that these artifacts are implicitly added to the target platform. This is for example useful if you want to rebuild a part of a Tycho reactor, or if you want to build against a locally built, newer version of an upstream project.

There are the following options to disable this feature:

  • Setting the CLI option -Dtycho.localArtifacts=ignore excludes locally built artifacts in one build. (tycho.localArtifacts=ignore may also be configured in the settings.xml; in this case, the default behaviour can be temporarily re-enabled with the CLI option -Dtycho.localArtifacts=default. Since Tycho 0.16.0.)
  • Deleting ~/.m2/repository/.meta/p2-local-metadata.properties resets Tycho's list of locally build artifacts, and therefore these artifacts will not be added to target platforms (unless, of course, the artifacts are installed again).

Filtering

See https://ci.eclipse.org/tycho/job/tycho-sitedocs/lastSuccessfulBuild/artifact/target/staging/target-platform-configuration/target-platform-configuration-mojo.html#filters

Dependency resolution troubleshooting

TODO

Run mvn with the flags -Dtycho.debug.resolver=true and -X to see debug output.

This will debug

  • Properties
  • Available IUs
  • JRE IUs
  • Root IUs

Listing IUs available

To list all the available IUs in an Eclipse repository (e.g. indigo), run:

$ java -jar plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar -debug -consolelog -application org.eclipse.equinox.p2.director -repository http://download.eclipse.org/releases/indigo/ -list

Command running with Luna and list Luna Repository

$ java -jar plugins/org.eclipse.equinox.launcher_1.3.0.v20140415-2008.jar -debug -consolelog -application org.eclipse.equinox.p2.director -repository http://download.eclipse.org/releases/luna/ -list
  • Java is used (instead of the eclipse binary) so that the console output appears in the shell window instead of a spawned window
  • Make sure your shell is inside the Eclipse root directory
  • You will need to replace that version number for org.eclipse.equinox.launcher with the one found inside your Eclipse installation.
  • You will need to replace the Eclipse repository with the one you want a list of.

This can be used to double check availability of bundle versions, and compare with what Nexus thinks is available with the source Eclipse repository.

Browsing a p2 repository

Just follow the instructions in the README to start it.

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