Having difficulty setting up Gradle multiproject build for existing repository layout

Question

I'm trying to craft a Gradle multiproject build for a situation in which my project layout is already dictated to me. I have something like this:

-->Shared\
---->SharedComponent1\
------>build.gradle
------>src\
...
---->SharedComponent2\
------>build.gradle
...
-->Product1\
---->ProductComponent1\
------>build.gradle
---->ProductComponent2\
------>build.gradle
...
---->build\
------>settings.gradle

My settings.gradle looks like this:

rootProject.name = 'Product1'
rootProject.projectDir = new File( "${ProjectsRoot}" )

include 'Shared:SharedComponent1'
include 'Shared:SharedComponent2'
include 'Product1:ProductComponent1'
include 'Product1:ProductComponent2'

When I run Gradle in the build folder like this:

gradle -PProjectsRoot=c:\my\project\root\dir projects

I get:

:projects

------------------------------------------------------------
Root project
------------------------------------------------------------

Root project 'build'
No sub-projects

To see a list of the tasks of a project, run gradle <project-path>:tasks
For example, try running gradle :tasks

BUILD SUCCESSFUL

i.e. it doesn't find the projects I'm trying to build. Is what I'm trying to do possible with Gradle's multiproject support? Or am I barking up the wrong tree?

Answer 1

For completeness, the settings.gradle that solved my specific example above is as follows:

rootProject.name = 'Product1'

def projectTreeRootDir = new File( "${ProjectsRoot}" )

// Shared components

def sharedRootDir = new File( projectTreeRootDir, 'Shared' )

include ':SharedComponent1'
project( ':SharedComponent1' ).projectDir = new File( sharedRootDir, 'SharedComponent1' )

include ':SharedComponent2'
project( ':SharedComponent2' ).projectDir = new File( sharedRootDir, 'SharedComponent2' )

// Product components

includeFlat 'ProductComponent1', 'ProductComponent2'

Clearly this doesn't scale to large numbers of subprojects and it could be done significantly better using the hints provided by Peter above.