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Gradle Manipulator @ Red Hat

Standardize Your Builds


GME (Gradle Manipulation Extension) is a set of Gradle plugins and a CLI that allow the alignment of versions of a Gradle project according to some external preference.

Two plugins make up the extension, the analyzer plugin and the manipulation plugin.

The job of the analyzer plugin is to generate a metadata file that contains altered dependencies for each project of a Gradle Project. The file is then meant to be used by the manipulation plugin to enforce the versions of the dependencies that are captured in the metadata file.

The metadata file is named manipulation.json and is created by the generateAlignmentMetadata task of the alignment plugin in the root directory of the target Gradle project. The file is in JSON format, may be read and written through this utility class. The Java source may be found here and the documentation is here. An example from the functional tests of the manipulation.json is here.


Applying the Plugin(s)

There are multiple ways that the plugins can be applied.

It should also be noted that the project itself contains a properly configured init script for the analyzer plugin (which gets released along with the plugin). Furthermore, when the analyzer plugin executes, it alters the main gradle script of the target project to include the manipulation plugin.

NOTE : The CLI is only available from version 1.4.

The CLI is capable of running arbitrary groovy scripts prior to the build. See here for further details on this.

Usage: GradleAnalyser [-dhV] [-l=<installation>] -t=<target>
CLI to optionally run Groovy scripts and then invoke Gradle.
  --[no-]colour           Enable (or disable with '--no-colour') colour output
                            on logging.
  -d                      Enable debug.
  -D=<String=String>      Pass supplemental arguments (e.g. groovy script
  -h, --help              Show this help message and exit.
  -l=<installation>       Location of Gradle installation.
  -t, --target=<target>   Target Gradle directory.
  -V, --version           Print version information and exit.

Apart from the Groovy scripting, the CLI can modify colour output, enable debug logging, pass extra -D parameters, specify the Gradle distribution to use and specify the target directory to operate on.

Note that the CLI will capture unmatched arguments and pass them directly to the Gradle build. For example, below --stacktrace, --init-script and the task exclusion of -x task-to-exclude are all passed to Gradle.

java -jar cli.jar --target=<gradle-project> -d
    -x task-to-exclude

It is possible to run the Gradle process using a different JDK by passing in the following parameter:<JDK-Location>

To obtain the CLI it may be downloaded from Maven Central here.

Init Script

If a development version is being used, the init script is placed during the build into analyzer/build/resources/main/analyzer-init.gradle. If a released version is being used, it is deployed as analyzer-<version>-init.gradleand may be found in Maven Central, i.e., for version 2.7,

Now, by executing

./gradlew --info --init-script analyzer-init.gradle generateAlignmentMetadata -DrestURL=http://some.da.server

you should get the manipulation.json file in the root of the project.

For detailed documentation on the parameters please see here.


Alignment Configuration

Customising the Manipulation Plugin Version

Warning : This option may lead to Alignment and Manipulation plugins being 'out of sync'. Therefore caution should be used when applying this option and only use it if absolutely necessary.

When running the alignment plugin (e.g. via the CLI), it is possible to configure the version of the Manipulation Plugin that is injected. By default the same version as the alignment plugin will be used (i.e. the current version). By setting manipulationVersion to a value (e.g. 2.6.) this version is requested instead.

Unresolved Dependencies

If the tool is not able to resolve certain dependencies then it may fail during the alignment phase. Set ignoreUnresolvableDependencies to true to ignore those (default: false).

Publish Plugin Hook

Certain project builds don’t apply the publish plugin directly (be it the legacy or current one); instead they implement their own ‘build plugin’ (e.g. within buildSrc) that itself then applies plugins. This can lead to the situation where this custom plugin is applied and actioned after the GME tooling plugin which therefore does not detect any publishing plugins. It is possible to list those custom plugins as ‘hooks’ that GME will detect, and attempt to customise the publishing again. It is a comma separated list with a single default entry of elasticsearch.esplugin.

General Configuration

Disabling the Plugins

You can disable GME using the manipulation.disable property:

$ gradle -Dmanipulation.disable=true...


The tool uses its own logging system (that backs onto the Gradle logging system).

Summary Logging

GME will output a summary of its changes at the end of the run. As well as reporting version and dependency alignment, it is also possible to report what hasn’t been aligned by setting the property reportNonAligned=true. This summary may also be output to a file by setting the property reportTxtOutputFile to the name of the file, e.g., alignmentReport.txt. The file’s path will always be relative to the execution root build directory.

Finally, it will also output the comparator summary as a JSON file. The file’s path will always be relative to the execution root build directory. By default, the file will be named alignmentReport.json. However, the name of this file may be changed by setting the reportJSONOutputFile property to an alternate name for the file.

  "executionRoot" : {
    "groupId" : "",
    "artifactId" : "foo-parent",
    "version" : "7.0.0.Final-rebuild-1",
    "originalGAV" : ""
  "modules" : [ {
    "gav" : {
      "groupId" : "",
      "artifactId" : "foo-parent",
      "version" : "7.0.0.Final-rebuild-1",
      "originalGAV" : ""

This JSON file may be read as POJO by using the JSONUtils class which utilises the json package.

Feature Guide

Below are links to more specific information about configuring sets of features in GME: