This project provides an Eclipse plugin for building, debugging, and deploying Google Cloud Platform applications.

End user documentation and installation instructions can be found on cloud.google.com.

TL;DR: mvn -Dtycho.toolchains=SYSTEM package should generate a p2-accessible repository in gcp-repo/target/repository.

Development

This project is built using Maven Tycho, a set of extensions to Maven for building Eclipse bundles and features.

Requirements

1. The Google Cloud SDK; install this somewhere on your file system.

2. The Eclipse IDE. It's easiest to use the Eclipse IDE for Java EE Developers package. You can use Eclipse 4.6 (Neon) or 4.7 (Oxygen) as we define a target platform to build and run against.

3. The m2eclipse plugin (also called m2e) is required to import the projects into Eclipse. m2eclipse is included in several packages, such as the Eclipse IDE for Java EE Developers package.

4. Maven 3.3.9 or later. Although m2eclipse is bundled with its own Maven install, Maven is necessary to test command-line builds.

5. JDK 7

6. git (optional: you can use EGit from within Eclipse instead)

7. Clone the project to a local directory using git clone https://github.com/GoogleCloudPlatform/google-cloud-eclipse.git.

##Configuring Maven/Tycho Builds

The plugin is built using Maven/Tycho and targeted to Java 7.

The tests need to find the Google Cloud SDK. You can either:

1. Place the SDK/bin directory on your PATH
2. Set GOOGLE_CLOUD_SDK_HOME to point to your SDK

Changing the Eclipse Platform compilation and testing target

By default, the build is targeted against Eclipse Mars / 4.5. You can explicitly set the eclipse.target property to neon (4.6) or oxygen (4.7).

$ mvn -Declipse.target=neon package

Configuring Maven/Tycho Toolchains

We use Tycho's support for Maven Toolchains to ensure that Java 8 features do not creep into the code. This support is enabled by compiling with the useJDK=BREE setting that ensures bundles are compiled with a JDK that matches the bundle's Bundle-RequiredExecutionEnvironment. This setting requires configuring Maven's toolchains to point to appropriate JRE installations. Tycho further requires that a toolchain defines an id for the specified Execution Environment identifier. For example, a ~/.m2/toolchains.xml to configure Maven for a Java 7 toolchain on a Mac might be:

<?xml version="1.0"?>
<toolchains>
  <toolchain>
    <type>jdk</type>
    <provides>
      <id>JavaSE-1.7</id> <!-- the Execution Environment -->
      <version>1.7</version>
      <vendor>oracle</vendor>
    </provides>
    <configuration>
      <jdkHome>/Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home/jre</jdkHome>
    </configuration>
  </toolchain>
</toolchains>

Note that jdkHome above specifies the jre/ directory: Tycho sets the default boot classpath to jdkHome/lib/*, jdkHome/lib/ext/*, and jdkHome/lib/endorsed/*. For many JDKs, including Oracle's JDK and the OpenJDK, those directories are actually found in the jre/ directory. Compilation errors such as java.lang.String not found and java.lang.Exception not found indicate a misconfigured jdkHome.

You can disable the use of toolchains by setting the tycho.toolchains property to SYSTEM.

Adding a new bundle/fragment

We normally put production code into a bundle and tests as a fragment hosted by that bundle, put under the plugins/ directory. For now we have been committing both the pom.xml and Eclipse's .project, .classpath, and .settings/ files.

Our CI process is configured to run our tests with JaCoCo, which requires some additional configuration to add new bundles and fragments in build/jacoco/.

Import into Eclipse

We pull in some dependencies directly from Maven-style repositories, such as Maven Central and the Sonatype staging repository, which isn't directly supported within Eclipse. We have a few hoops to jump through to set up a working development environment.

Assemble the IDE Target Platform

The Eclipse IDE and Tycho both use a Target Platform to manage the dependencies for the source bundles and features under development. Although Tycho can pull dependencies directly from Maven-style repositories, Eclipse cannot. So we use Tycho to cobble together a target platform suitable for the Eclipse IDE.

$ mvn -Pide-target-platform package

This command builds the project, but also creates a local copy of the target platform, including any Maven dependencies, into eclipse/ide-target-platform/target/repository.

The target platform is affected by the eclipse.target property, described below.

Steps to import into the Eclipse IDE

1. Setup JDK 7 in Eclipse

2. Select Window/Preferences (on Mac Eclipse/Preferences).

3. Under Java/Installed JREs click Add.

4. Select Standard VM and click Next.

5. Select the folder that contains the JDK 7 installation by clicking Directory.

6. Click Finish.

7. Select Java/Installed JREs/Execution Environments page.

8. Click on JavaSE-1.7 in the list on the left under Execution Environments:.

9. The JDK just added should show up in the list on the right along with other installed JDKs/JREs. Set the checkbox next the the JDK 7 added in the previous steps to mark it as compatible with the JavaSE-1.7 execution environment.

10. Click OK.

11. Set up the Target Platform: you will need to repeat this process whenever items are changed in the target platform, such as a new release of the appengine-plugins-core.

12. As described above, you must first build the target platform with Maven:

    $ mvn -Pide-target-platform package

13. Open the Preferences dialog, go to Plug-in Development > Target Platform.

14. Click Add... > Nothing to create a new Target Platform.

15. Name it GCP IDE Target Platform.

16. Select Add > Software Site.

17. Select the Add... button (found beside the Work with: field) and then select Local to find a local repository. Navigate to .../eclipse/ide-target-platform/target/repository, and click OK.

18. Once the main content populates, check the Uncategorized item to pull in all items. Click Finish.

19. Click Finish to complete the new target platform definition.

20. Select your new target platform (instead of Running Platform) in the Target Platform preferences.

21. Click OK to load this new target platform.

22. Eclipse will load the target.

23. Import the projects

24. Select File/Import... menu in Eclipse.

25. Select Existing Maven Projects from the list.

26. Click Browse... and select the directory that contains the project.

27. Under Projects: the pom.xml files representing modules should be displayed. Make sure that all of them are selected, and click Finish.

28. Maven may prompt you to install several additional plugin connector plugins from Tycho if they are not already installed. Click Finish to install them. If Eclipse prompts you to install any other plugins, do so.

29. Restart Eclipse when prompted.

30. Check the imported projects:

31. There should be no errors in the Markers or Problems views in Eclipse. However you may see several low-priority warnings.

    1. You may see Maven-related errors like "plugin execution not covered by lifecycle configuration". If so, right-click on the problem and select Quick Fix > Discover new m2e connectors and follow the process to install the recommended plugin connectors.

32. Create and initialize a launch configuration:

33. Right-click the gcloud-eclipse-tools.launch file under the google-cloud-eclipse module in the Package Explorer.

34. Select Run As > Run Configurations...

35. Set variables required for launch:

1. Go to the second tab for `Arguments`

1. Click the `Variables...` button for `VM argument:`

1. Click the `Edit variables...` button

1. Click `New...`

1. Set the name to `oauth_id`, and the value to the value you want to use
(description optional)

1. Click `OK`, the variable will appear in the list

1. Repeat steps 6-8 but use `oauth_secret` as the name and use the
corresponding value

1. Click `OK` to close the edit variables dialog

1. Click `Cancel` to close the variable selection dialog

1. Click `Apply` to apply the changes to the run config

1. From the Run menu, select Run History > gcloud-eclipse-tools

2. A new instance of Eclipse launches with the plugin installed.

Updating Target Platforms

Updating the .target files

We use Target Platform files (.target) to collect the dependencies used for the build. These targets specify exact versions of the bundles and features being built against. We currently maintain two target platforms, targeting the latest version of the current and previous release trains. This is currently:

• Eclipse Mars (4.5 SR2): eclipse/mars/gcp-eclipse-mars.target
• Eclipse Neon (4.6): eclipse/neon/gcp-eclipse-neon.target
• Eclipse Oxygen (4.7): eclipse/oxygen/gcp-eclipse-oxygen.target

These .target files are generated and should not be manually updated. Updating .target files directly becomes a chore once it has more than a couple of dependencies. We instead generate these .targets from Target Platform Definition .tpd files. The .tpd files use a simple DSL to specify the bundles and features, and the location of the repositories containing them.
The .tpd files are processed using the TPD Editor which resolves the specified dependencies and creates a .target. The process is:

1. Install the TPD Editor, if necessary
   • Use Help > Install New Software and specify http://mbarbero.github.io/fr.obeo.releng.targetplatform/p2/latest/ as the location.
   • Restart Eclipse when prompted
2. Open the .tpd file in Eclipse.
3. Make any necessary changes and save.
   • Note that the TPDs specify artifacts using their p2 identifiers. Bundles are specified using their OSGi Bundle Symbolic Name (e.g., org.eclipse.core.runtime). Features are specified using their Feature ID suffixed with .feature.group (e.g., org.eclipse.rcp.feature.group).
4. Right-click in the editor and choose Create Target Definition File to update the corresponding .target file.

Both the .tpd and .target files should be committed.

Updating Dependencies

The IDE Target Platform needs to be rebuilt at the command line and reimported into Eclipse when dependency versions are changed:

1. mvn -Pide-target-platform package
2. Preferences > Plug-in Development > Target Platforms
3. Select your target ("GCP IDE Target Platform") and click Edit
4. Select the location and click Reload to cause any cached info to be discarded.
5. Click Edit and then select Uncategorized.
6. Finish / OK until done.

Updating the Eclipse IDE Target Platforms

The IDE Target Platform, defined in eclipse/ide-target-platform, may need to be updated when dependencies are added or removed. The contents are defined in the category.xml file, which specifies the list of features and bundles that should be included. This file can be edited using the Category editor in Eclipse. Ideally the version should be specified as "0.0.0" to indicate that the current version found should be used. Unlike the .tpd file, the identifiers are not p2 identifiers, and so features do not require the .feature.group suffix.