gradle-4.6-all

# Using composite builds in a hierarchical multirepo project This sample demonstrates how composite builds can be used to develop a hierarchical project that is composed from different Git repositories. Instead of Gradle subprojects in a multiproject build, this example uses separate Gradle builds included into a composite. In addition to the benefits of a multirepo architecture, using a Gradle composite build in this way allows a developer to easily choose which modules to develop as source dependencies and which to integrate via a binary repository. ### Running `multirepo-app` with dependencies from included builds In the first instance, all of the required dependencies are present as builds in the `modules` directory. In a real-world example, these could well be clones of different Git repositories. In order to avoid hard-coding the included builds to load, the `settings.gradle` file in `multirepo-app` loads each of these builds dynamically: ``` file('modules').listFiles().each { File moduleBuild -> includeBuild moduleBuild } ``` When the `multirepo-app` build is executed, these module builds are used to generate the dependent artifacts: ``` gradle run ``` And the 'dependencies' report shows the dependency substitution in action: ``` gradle dependencies --configuration compile ``` >>> ``` compile - Dependencies for source set 'main'. +--- org.sample:number-utils:1.0 -> project :number-utils \--- org.sample:string-utils:1.0 -> project :string-utils \--- org.apache.commons:commons-lang3:3.4 ``` ### Switching to use binary dependency As long as the modules are available in a binary repository, the `multirepo-app` build will continue to work even if you don't have some modules available locally. In this case Gradle will use a binary dependency downloaded from a repository instead. #### Preparing the binary repository To demonstrate this functionality, we first need to publish each module to a binary repository. In this case we use a local file repository for this purpose: ``` gradle :publishDeps ``` The `publishDeps` creates and uploads the artifacts for each included build. It is defined in `multirepo-app` as follows: ``` task publishDeps { dependsOn gradle.includedBuilds*.task(':uploadArchives') } ``` #### Removing the local module source With module artifacts available in a repository, we can now remove the module sources from the build. Since the composite is configured to automatically load available modules, this is as easy as deleting one or more module directories. ``` rm -r modules/string-utils gradle run ``` Note that the `number-utils` dependency is still satisfied by the included build, while the `string-utils` dependency is now resolved from the repository. The 'dependencies' report shows the dependency substitution in action: ``` gradle dependencies --configuration compile ``` >>> ``` compile - Dependencies for source set 'main'. +--- org.sample:number-utils:1.0 -> project :number-utils \--- org.sample:string-utils:1.0 \--- org.apache.commons:commons-lang3:3.4 ``` ### Including an external library as a submodule The power of this configuration can be demonstrated by adding the external 'commons-lang' build directly to the composite. ``` git clone http://git-wip-us.apache.org/repos/asf/commons-lang.git modules/commons-lang --branch master --depth 1 gradle --project-dir modules/commons-lang init gradle run ``` You can see the external transitive dependency `commons-lang` being replaced with the local project dependency by running: ``` gradle dependencies --configuration compile ```