gradle tar include nested files at top level - gradle

Question

In gradle (1.9), I have multiple subprojects. Each one uses the application plugin to create a tar and cli. I am trying to get all these tars into a unified tar, but I am having a lot of trouble.
Here is the tar format I am looking for:
${project.name}/${subproject.name}.tar
I have tried using both the Tar task and the distribution plugin, but for each one, I am not able to find a clean way to just get the generated tars (or any tar), and put them at top level, excluding everything else.
Here is a sample using the distirbution pluging, but its not giving the output I like
apply plugin: 'distribution'
distributions {
testing {
contents {
from(".")
exclude "*src*"
exclude "*idea*"
exclude "*.jar"
exclude ".MF"
filesMatching("**/build/distributions/*.tar") {
if(file.name == "${project.name}-testing.tar") {
exclude()
} else {
name file.name
}
}
}
}
}
Here is what I would like (but not working):
apply plugin: 'distribution'
distributions {
testing {
contents {
include "**/*.tar" // shows up at top level
}
}
}
EDIT:
Getting closer.
distributions {
testing {
contents {
from subprojects.buildDir
includeEmptyDirs false
include "**/*.tar"
exclude "**/${project.name}-testing.tar"
}
}
}
This will give me ${project.name}/distribution/${subproject.name}.tar

Answer 1

Here is the solution for your problem. Put the following to the root project:
task distTar(type: Tar) {
destinationDir = new File("$buildDir/distributions")
baseName = 'unifiedTar'
}
subprojects {
// definitions common to subprojects...
afterEvaluate {
def distTar = tasks.findByName('distTar')
if(distTar) {
rootProject.distTar.dependsOn distTar
rootProject.distTar.inputs.file distTar.archivePath
rootProject.distTar.from distTar.archivePath
}
}
}
then invoke "build distTar" on the root project - it will assemble "unifiedTar.tar" in "build/distributions" subfolder (of the root project).
How it works:
"task distTar(...)" declares a new task of type Tar in the root project.
"subprojects" applies the specified closure to each subproject.
"afterEvaluate" ensures that the specified closure is called AFTER the current project (in this case subproject) is evaluated. This is very important, because we are going to use properties of the subproject which are defined only after it's evaluation.
"tasks.findByName" allows us to determine, whether the given task is defined for given project. If not, it returns null and the following code is not performed. This way we stay agnostic regarding the nature of the subproject.
"dependsOn" ensures that distTar of the root project depends on distTar of the given project (and, therefore, is executed later than it).
"inputs.file" ensures that distTar on root project is not executed, if none of the constituent tars has changed.
"from" adds constituent tar to unified tar.